The Evolution of Emotion - PDF

11 The Evolution of Emotion Key Concepts universal emotions emotional expression emotional experience emotion and motivation wheel of emotions James–Lange theory limbic system amygdala orbitofrontal cortex lat- eralisation of emotions autonomic nervous system...

11 The Evolution of Emotion Key Concepts universal emotions emotional expression emotional experience emotion and motivation wheel of emotions James–Lange theory limbic system amygdala orbitofrontal cortex lat- eralisation of emotions autonomic nervous system display rules preparedness theory positive and negative emotions locationist neuroscience view Evolutionary psychologists maintain that the mind was designed to solve specific problems that our ancestors faced on a regular basis. If this is the case then, in addition to cognitive mechanisms, surely emotions also serve an adaptive purpose. Such a notion can be traced back to Darwin, who in 1872 argued that a number of emotional expressions are common to all cultures. Following a century when this claim was either disputed or, more commonly, ignored, most psychologists today accept that at least some basic expressions are shared by all cultures. But such a conclusion raises a number of further questions. If certain emotional expressions are universal then this suggests that they are adaptive – but how can a facial expression aid survival and reproduction? Moreover, if we all express basic emotions in the same way does this mean that we all experience emotions in the same way? If we do, how might these specific internal states also be adaptive? In this chapter we consider the evidence that emotions are innate and universal from three areas of research – com- parisons between different cultures, comparisons between ourselves and our primate relatives, and the neurological bases of emotions. Finally, we examine the proposed functional explanations for specific emotional states. What Are Emotions? If you ask a number of psychologists today what is meant by the term ‘emotions’ you will proba- bly receive as many definitions as the number of psychologists you ask. Most, however, would not dispute a definition that incorporates positive and negative feelings which involve physiological, cognitive and behavioural reactions to internal and external events. Evolutionists might agree with such a definition but would point out that this is a proximate definition of emotions, while they are more interested in ultimate explanations – why such mechanisms came about. One evolutionary psychologist who has a special interest in emotions is Randolph Nesse of Arizona State University. Nesse, a psychiatrist by training, has explicitly defined emotions in relation to their evolutionary functions:  Why Do We Have Emotions? 285 Figure 11.1 Darwin was regularly caricatured by popular magazines of the day. In this 1871 James Tissot print from the magazine Vanity Fair, we see him expressing exaggerated glee at his own fame just a few months before his book examining emotional expres- sions was published. Emotions are specialized states that adjust physiology, cognition, subjective experience, fa- cial expressions, and behavior in ways that increase the ability to meet the adaptive challenges of situations that have recurred over the evolutionary history of a species. (Nesse 2019, 54) This is a particularly appropriate definition for our purposes since not only does it incorporate the ultimate level of analysis, it also suggests that each emotional state will be related to quite specific circumstances that our ancestors faced. You might like to refer back to Nesse’s definition when con- sidering the rest of this chapter as we explore what evolutionary psychology has to say about the ‘ins and outs’ of emotions – that is, both their internal experience and external expression. Why Do We Have Emotions? In Chapter 9 we saw how certain cognitive processes may be thought of as adaptations which help us to solve the sort of problems that our ancestors regularly encountered. But humans and other animals are more than just problem-solving automata. Cognition is motivated to some specific end, whether that is to obtain food, avoid injury or predation, to find a suitable sexual partner, to protect offspring or to avoid exploitation by others. Evolutionists argue that emotions fulfil this crucial mo- tivational role. Works of science fiction frequently present emotions as a weakness, if we could act out of pure, cold logic like Mr Spock from the original Star Trek, then, being unencumbered by the baggage of emotions, we would be better able to perform the various acts that help us to live long and prosper. But herein lies the problem, without emotions to motivate cognition why would we do anything at all? Think about it for a second. You work hard on your course because of your desire to obtain a good qualification (and also, perhaps, because you fear poor performance), you help someone in distress because you feel compassion 286 The Evolution of Emotion to avoid the shame and guilt of being labelled a freerider and so on. Actually the fictional figure of Mr Spock is really a con. He does have emotions – albeit a little different from our own. Although he rarely shows warmth or anger he frequently describes events as ‘fascinating’ and ‘intriguing’. In other words, there are many things which he finds rewarding because they are interesting (this incidentally is also true of the New Generation equivalent of Mr Spock – Data – and of Star Trek Voyager’s ‘emotionless’ Tuvok and Enterprise’s T’Pol). Finding something rewarding (or indeed the opposite – punishing) means that we must, at some level, have an emotional response to it. In fact American psychologist Carroll Izard (1977) considers ‘interest’ to be the most frequently experi- enced emotion. Emotions motivate us to do things. A human without emotions would be akin to having the most complex computer ever invented sitting around doing nothing, not because it wants to do nothing, but because it is unable to want or not want to do anything! This is as true of emotions such as anger, fear and sadness as it is of interest. Emotions are the driving forces that propel us to make use of the cognitive abilities we have. Such a statement is nothing new. What evolutionary psychology might add to this under- standing is the notion that emotions exist to make us want to do the sorts of things that made our an- cestors successful, in an inclusive fitness sense, and to avoid doing the things that would have made them less successful. If this is the case then we might be able to develop a more precise understand- ing of the function of each specific emotion (Nesse, 1990; 2009). But where did this idea come from and what might the evolutionary approach tell us about the relationship between emotions, evolu- tion and behaviour? In this chapter we will explore both the current thinking among evolutionists on specific emotions and the historical roots of treating emotions as the products of natural selection. So, when it comes to emotions, on whose shoulders do modern evolutionary psychologists stand? Darwin, James and Freud and the Early Study of Emotions Many psychologists today regard the pioneering American psychologist William James as pre- eminent in considering emotions as ‘instinctive’. But, as is so often the case, it was Darwin who first considered the notion. Twelve years prior to James’ famous essay on emotions, ‘What is an emo- tion?’ (1884), Darwin published The Expression of the Emotions in Man and Animals (1872/1998), in which he explicitly stated not only that emotions served the purpose of aiding survival and repro- duction in our ancestors, but that they are currently used in the same way cross-culturally. Darwin was not alone, however, in considering emotions to be universal. During the last 30 years of the nineteenth century, Darwin, Freud and James all spilt much ink on the topic of human emotions and their universality. The Purpose of Emotions in Humans as Seen by Darwin, James and Freud Darwin (1809–82), having observed the same emotions on the faces of individuals from a range of different isolated cultures, argued that such expressions must be inherited rather than learned. Dar- win saw emotions as internal psychological states, the expressions of which are rudimentary ves- tiges of behaviour handed down from our ancestors (Workman, 2014; Workman and Taylor, 2019). More specifically he argued that human facial expressions had a common evolutionary origin with our primate relatives. In The Expression of the Emotions in Man and Animals, Darwin introduced three principles around which he considered emotions to be based:  Darwin, James and Freud and the Early Study of Emotions 287 1. Serviceable associated habits. This means that, when in a specific emotional state, a person is likely to demonstrate the same type of expression and the same type of body posture. Interesting- ly, although Darwin saw expressions as having value for our primitive ancestors, he believed that they were no longer functional in modern humans. 2. Antithesis. Here the idea is that the expression of positive and negative emotions occur in pairs – so a relaxed and open body posture is seen in someone who is happy and friendly whereas the opposite – a tense posture – is seen in an angry person in an aggressive state. Moreover, when trying to disguise our feelings we may unconsciously attempt to present a body posture which is the opposite of the way we are really feeling. 3. Direct action of the excited nervous system on the body independently of the will. When in a strongly aroused state, our facial expression, intonation and body posture all let others know about our internal state. Hence, we tremble with fear, we withdraw physically from a disgusting scene and our whole body may shake when we laugh at something overwhelmingly funny. All of these things occur without conscious effort. Box 11.1 Emotion and Motivation Emotion, motivation and cognition are often considered to be the big three areas that psycholo- gists study. We considered cognition in Chapter 9, but the remaining two are often seen to over- lap. Emotion and motivation are both associated with arousal and goal-directed behaviour (Buck, 1988; 2014; Toates, 2011; 2020). How might we distinguish between these two concepts? Ross Buck of the University of Connecticut has made a special study of motivation and emotion. He sees motivation as ‘a potential for the activation and direction of behavior inherent in a system of behavior’ (Buck, 1988, 9). In contrast, he suggests emotional states have three components not normally associated with motivation (Buck, 1988; 2014): Emotions involve feelings such as anger, fear and happiness. Emotions are associated with expressive behaviours such as smiling or crying. Emotions are associated with peripheral physiological responses such as changes in heart rate or sweating (or at least it is the emotional ingredient of motivation that is directly associated with these responses). Although Buck’s definition might help to distinguish between the two, we should also bear in mind that, in some respects, the two may be considered as part and parcel of each other in that we only react emotionally when something affects our progress towards our motives and goals (Lazarus, 1991). If this is the case, then perhaps we cannot have one without the other. But which came first – are we motivated because we feel emotional about something or do we develop an emotional state because we feel motivated towards a goal? This chicken-and-egg scenario is dif- ficult to resolve – but, given that we have little difficulty in attributing motivations to animals but often feel uncomfortable using emotionally laden terms, then it might be argued that emotions evolved later to help serve motivations. In this chapter when we use the term emotion we take it for granted that there will also be motivation involved. 288 The Evolution of Emotion Figure 11.2 Woodblock prints of facial expressions of human emotions from The Expression of the Emotions in Man and Animals by Charles Darwin (1872). From top left to bottom right: neutral, sorrow in child, sorrow in man, helplessness, sneering, outrage, astonishment, happiness, contempt. James (1842–1910) specifically developed Darwin’s ideas arguing that, rather than the physical signs of an emotion following an internal state, the reverse is the case. So we feel fear because we tremble, rather than the other way round (James, 1884). In this way humans were seen to have evolved to react to our inward and outward bodily signs of emotions. In particular, James argued that the brain monitors the state of the viscera (that is ‘gut feelings’) and then we react to these signs with the appropriate internal state. This idea was also put forward independently by Danish psychologist and philosopher Carl Lange (1885/1912) at around the same time and hence came to be known as the James–Lange theory of emotion. This theory was well accepted by psy- chologists for 40 years until it was criticised by physiologist Walter Cannon who, in 1927, observed that individuals who had had their viscera accidentally severed from the central nervous system still  Twentieth-Century Rejection of Universal Emotions 289 felt emotions. Although the James–Lange theory is no longer central to the psychology of emotions, experimental evidence from Ekman and colleagues suggests that there is an element of truth in it. Subjects told to pull certain faces then reported that they began to feel the emotion depicted by such expressions (Ekman, 1992). Freud (1856–1939), like James before him, was very much influenced by Darwin and ap- plied his principles to understanding and treating people who had serious emotional problems such as hysteria. He specifically used the idea of antithesis to help describe the behaviour of some of his patients. Freud also developed the concept of human behaviour being very much driven by the pursuit of pleasure and the avoidance of pain – the pleasure–pain principle, which he traced back to Darwin. Although, in contrast to much of twentieth-century psychology, Freud considered emotions as central to understanding human behaviour, his work has been heavily criticised by mainstream psychology and, with the exception of Christopher Badcock of the London School of Economics, Freud’s ideas have not had a major impact on the writings of evolutionary psychologists (Badcock, 2000). The Wheel of Emotions Back in 1980 Robert Plutchik attempted to create a wheel of emotions in order to help us under- stand the range of human emotional states and their relationships (see Figure 11.3). Plutchik was very much a disciple of evolutionary theory and, following Darwin, consid- ered eight primary emotions had evolved in order to aid communication and survival. To Plutchik each of these primary emotions had a polar opposite. Hence, for example, joy is considered to be the opposite of sadness and disgust is the opposite of trust. Also, in this scheme the primary emotions can be combined to provide secondary emotions. An example of this would be joy and trust, which when combined, become love. Finally, the intensity of the colour represents the strength of emotion experienced. This means that, for example, apprehension can develop into the stronger emotional state of fear and this, in turn, can develop into the even more intense state of terror (note this is ex- pressed by a deeper shade of green in Figure 11.3). Today, as we will see (Box 11.2), evolutionists don’t entirely agree on how many basic emotional states humans have (and even on whether such basic emotions exist!). Furthermore, most do not subscribe to the notion of polar opposite pairings of emotional states. Despite these reservations, Plutchik’s scheme was one of the first in modern psychology to consider the adaptive, universal nature of emotional states and the concept of the wheel of emotions has therefore been influential in stimulating research into the origins of emo- tional states. Twentieth-Century Rejection of Universal Emotions Despite the ideas of Darwin, James and Freud, during most of the twentieth century, emotions were largely ignored by social scientists (Barrett, 2018). Many of those who did consider them took either a behaviourist stance, seeing most of behaviour as the outcome of conditioned learning (Skinner, 1957; see Chapter 10), or in a similar vein, treated human behaviour as almost infinitely malleable. This latter SSSM view of emotional expression was particularly associated with husband-and-wife team Gregory Bateson and Margaret Mead (see e.g. Mead, 1928). These social anthropologists took issue with Darwin’s innate view of emotions and Mead, in particular, argued vigorously that each culture develops its own unique set of emotions. She even claimed that in at least one society – 290 The Evolution of Emotion Figure 11.3 Plutchik’s wheel of emotions whereby we have eight primary emotions which occur in polar opposites and secondary emotions arise from combinations of these primary states. Samoan – there was no such emotion as sexual jealousy. Today it is difficult to over-state how great an impact this blank-slate view of human nature had on the development of the social sciences. The SSSM that prevailed throughout much of the twentieth century may well have been one of the rea- sons that many psychologists shied away from investigating the universality of human emotions. If each culture has its own set of emotions then this would have been a fruitless task. Today, however, much of Mead’s work on cultural differences in emotions has been discredited due to problems of objectivity and preconceptions. According to the anthropologist Derek Freeman, Mead was duped by two Samoan girls who engaged in a game of misleading her about the emotions and general practices of their culture (Freeman, 1983; 1999; Ekman, 1998; see also Chapter 14). Freeman’s own study of Samoan society revealed that sexual jealousy was as common there as anywhere else. In- deed, during the last 30 years there has been growing evidence that Darwin was correct in his view of the universality of human emotions – at least as far as expressions are concerned (see Box 11.2). The Nature and Function of Emotions Following the work of researchers such as Freeman and Ekman there has, since the 1990s, been a growing interest in reconsidering emotions not as culturally specific phenomena, but as adaptations. As we’ll see later, today a number of researchers have been strongly influenced by Darwin’s ideas on emotion (see ‘proposed functional explanations for specific emotional states’ later).  Emotional Expression and Emotional Experience 291 Emotional Expression and Emotional Experience Psychologists are generally on much firmer ground when discussing emotional expression than the internal subjective states that we all experience. Facial expressions and body language can at least be observed and, to a degree, quantified. Comparisons can also be made between ourselves and our primate relatives – if similar expressions are observed under broadly similar circumstances then this might help us to understand the roots of such emotions (see Box 11.3). How a person really feels inside, however, is very difficult to determine – we can only use what they say and the expression and intonation they use as indirect indications of their internal state. Then, using our own experience of emotions, we can attempt to piece together how they are feeling. Attempting to quantify such internal states in the lab is fraught with problems since people notoriously portray themselves in a dignified and positive light. In fact, although we are often told to be more open about our feelings, social life would grind to a standstill if everybody continually reported their moment-by-moment internal state to the world. Also, at least in Western industrialised society, we are frequently embar- rassed (another emotion) when asked about our emotions. Due to this we keep many of our feelings to ourselves and modify much of what we give away to others about our current internal state. Per- haps a better way to study emotions is to examine what is going on in the brain when we experience them. If emotions really are innate universal features of humans then perhaps we can expect to see a designated neural substrate for the generation, recognition and processing of such states. Box 11.2 Six Universal Facial Expressions? Almost 100 years after Darwin first proposed that emotional expressions are universal, Paul Ekman and his colleague Wallace Friesen provided evidence that helped to validate this view. In the late 1960s, Ekman and Friesen reported that the members of an isolated society living in a remote part of New Guinea – the South Fore people – were able both to identify and to copy a number of facial expressions as used by Westerners. The South Fore people were also able to confirm that they used specific expressions under the same sort of circumstances as people in the West. Moreover, when Ekman and Friesen presented photographs of the South Fore people using various facial expressions to denote specific emotions to their students back in the United States, the latter were immediately able to identify such emotions (Ekman and Friesen, 1967; 1969; 1971). This suggests emotional expressions can be perceived as adaptations because the possibility of an isolated people developing and using by chance exactly the same facial expres- sions under the same circumstances as ourselves is extremely small. While this is supportive evidence for Darwin’s belief that many emotional expressions are universal, we should not see them as hard-wired with each having a specific brain circuit dedicated to just one emotional state. Rather today a number of experts consider emotions as overlapping states which inter- weave with one another leading, through commonly experienced emotional situations, to the basic emotional expressions researchers such as Ekman and Friesen have observed (Barrett, 2013; 2018; Nesse, 2019). To be fair to them, Ekman and Friesen have not suggested emotional expressions are hard-wired, but that they are the outcome of common recurrent selective pres- sures across cultures. Also, as Ekman has subsequently suggested, we should not see each emo- tion as a single affective or psychological state but rather as a family of related states (Ekman and Cordaro, 2011).  292 The Evolution of Emotion Box 11.2 (cont.) Based on their original South Fore studies and subsequent observations in more than 20 other countries Ekman and Friesen suggest there are at least six basic universal facial expressions to denote human emotions – surprise, anger, sadness, disgust, fear and happiness. (Note Ekman has subsequently suggested contempt may also be a universal facial expression; see e.g. Ekman and Cordaro, 2011.) Since the time of Ekman and Friesen, a number of other studies have examined the question of basic universally recognised emotional expressions. In 2002 a meta-analysis considering over 100 separate studies and with more than 20,000 participants was published which confirmed the universality of basic human facial expressions (Elfenbein and Ambady, 2002). Despite this, there remains a degree of dispute among these ‘basic emotion theorists’ as to how many of these we have. Philip Johnson-Laird and Keith Oatley (1992), for example, have suggested that there are five universal emotions – all of Ekman and Friesen’s bar ‘surprise’ – while Carroll Izard suggests there are eight (Izard, 1977; 1992; 1994; see also Plutchik’s ‘wheel of emotions’ above). Clearly, we all show more than between five and eight different emotional facial expressions – most emo- tion theorists suggest that the large number that we all demonstrate is due to blending or mixing of these basic emotions, rather like the way that a very large number of hues may be produced from a small number of primary paint colours (LeDoux, 1996; 2012). Figure 11.4 From top left to bottom right: surprise, anger, sadness, disgust, fear, happiness – Lance Workman posing six universal emotional expressions. Seeing Emotions in the Brain – the Neuroscience of Emotional Experience As we saw in the definition provided by Nesse, there are three components to emotions – physio-  Seeing Emotions in the Brain – the Neuroscience of Emotional Experience 293 behavioural dimensions but recent advances in neuroimaging techniques (i.e. brain scans) have allowed scientists to gain insights into their physiological bases. Using PET (positron emission tomography) and fMRI (functional magnetic resonance imaging) scans, neuropsychologists have begun to uncover what is going on in the human brain when experiencing or viewing emotions. This is a new and revolutionary way of objectively studying emotions. Box 11.3 Similarities between Ourselves and Other Primates in Facial Expressions Provide Clues about the Origins of Human Facial Expressions Darwin was very taken by the highly expressive faces of primates and saw parallels with humans in the ‘grinning’ and ‘laughing’ faces that they frequently pull. Young orangs, when tickled, likewise grin and make a chuckling sound. (Darwin, 1872/1998, 132) Having observed similar facial gestures in humans and primates under broadly similar circum- stances, Darwin suggested that a number of these gestures may have arisen from a common simian ancestor. Observational work by British and German ethologists Richard Andrew (1963a; 1963b) and J. van Hooff (1967; 1972), respectively, have helped to flesh out this original suggestion. Andrew sees primate facial expressions as a secondary consequence of the vocalisations they produce when in an emotional state. The shrill shriek that a number of monkeys make when in fearful circumstances, for example, necessitates pulling back the lips into a ‘fear-grin’. Such Figure 11.5 Chimpanzees showing a range of emotional expressions – smiling, laughing and bored? 294 The Evolution of Emotion Box 11.3 (cont.) a grin is common to monkeys and humans. Andrew argues that, having evolved in order to allow the relevant sound to be made, such a facial gesture may often be used silently by ourselves and other primates today. Van Hooff, likewise, has observed and documented homologous (shared derived) expres- sions in humans and other primates. He sees two dimensions in pro-social gestures – ‘friendli- ness’, which involves a non-threatening baring of the teeth, and ‘playfulness’, which involves an open mouth and a staccato vocalisation. To put it in human terms, friendliness involves smiling and playfulness involves laughing. In this way smiling and laughter form a continuum with two dimensions. According to van Hooff, the silent bared-teeth display originated as an appeasing signal and later evolved into a friendly gesture in a number of primate species including our own. Figure 11.6 The development of facial signals in primates.  Seeing Emotions in the Brain – the Neuroscience of Emotional Experience 295 Box 11.3 (cont.) The open-mouthed vocal gesture, however, may be used as an invitation to play (all primates studied engage in playful activity). Van Hooff ’s scheme for the evolutionary development of laughter and smiling is shown above. The evolutionary development of laughter and smiling from primitive primates to humans was suggested by van Hooff. On the right we see the development of laughter, in the centre smil- ing and on the left anger (from van Hooff, 1972). Although the precise origin and specific func- tion of given facial gestures is still an area of debate, there is clear evidence that we do share a number of such signals with other primates and that we do use them under broadly similar social circumstances (see e.g. Parker, as cited in the 1998 edition of The Expression of the Emotions). The Locationist Perspective Much of behavioural neuroscience is based on a locationist view of the relationship between specif- ic emotional categories and particular areas of the brain. That is, states such as sadness and fear are strongly associated with specific locations in the brain (Lindquist et al., 2012). Some are in the outer layer of the brain known as the cortex whereas others lie beneath in the sub-cortex. Based on a num- ber of scanning techniques combined with deficits in response following brain damage and exper- iments conducted on other mammalian species, four areas of the brain (illustrated in Figure 11.7), Figure 11.7 Locationist view of correspondence between emotional processing and brain regions, with specific are- as of the brain being responsible for specific emotions. (a) Lateral view (side). (b) Sagittal (a cut down the midline of the brain to separate the two cerebral hemispheres). (c) Ventral view (viewed from beneath). (d) Coronal view (cut through the middle of the brain viewed from the front). In these brain images the following emotional states are repre- sented: fear, amygdala 296 The Evolution of Emotion have received a fair degree of supporting research for the locationist conception of emotions. Hence we consider each in turn concentrating mainly on the amygdala and the OFC as these are the main areas on which evolutionists have focused their attention. The Anterior Cingulate Cortex The ACC, or anterior cingulate cortex, is a portion of the cortex that lies down in the large lateral groove (the Sylvian fissure) which divides the two sides of the forebrain just above the corpus callo- sum (the large bundle of nerve fibres which allow for information transfer between the hemispheres). It is known to have numerous connections with both the ‘cognitive’ prefrontal cortex and the ‘emo- tional’ limbic system. Behavioural neuroscientists consider that, by processing activity from both of these areas, the ACC plays an important role in emotional regulation and social cognition (Ray, 2013). While its activity has been implicated in processing sadness, it may well do so by helping to manage this and other uncomfortable emotions. Functional neuroimaging techniques suggest that the ACC has abnormal patterns of activation in patients suffering from PTSD (post-traumatic stress disorder; Etkin and Wager, 2007). It is also believed to be involved (in collaboration with the insula; see below) in processing the emotional aspects of both physical pain and emotional pain caused by social rejection (Toates, 2011). Interestingly, in his book The Astonishing Hypothesis, co-discoverer of the structure of DNA Francis Crick suggests the ACC is the centre of free will (Crick, 1994). The Insular The insular is a small portion of the cortex down deep in the lateral fissure that separates the frontal and parietal lobes from the temporal lobe. It was largely ignored until the development of scanning techniques demonstrated how active it is in a wide range of emotional states including disgust, craving, pain and love. Having a multitude of neural connections to areas such as the amygdala and the ACC, the insular is involved in a wide range of activities including disgust, social emotional responses (including how much we ‘warm’ to others) and pain (Nieuwenhuys, 2012). Because it is involved in processing both emotional and physical pain, it can be said to have ‘dual functionality’ (Kang et al., 2011). The fact that this small portion of the brain (the insular makes up only 2 per cent of the cortex) can process both physical and psychological pain and warmth has led to the intriguing suggestion that the perception of interpersonal warmth may, over our evolutionary history, have ‘scaffolded’ on top of the perception of physical warmth (and conversely coldness; Kang et al., 2011). In support of this, when Kang et al. (2011) had participants play an economics games after being primed with a hot or a cold object, they found that fMRI scans led to different activity in the insular under the two temperature conditions. Moreover, when Story and Workman (2013) asked participants to play the prisoner’s dilemma (see Chapter 8) while holding an object, they observed a greater degree of cooperation when holding a warmed ‘hand-warmer’ than when holding a cooled one. This might help to explain why salespeople often offer potential customers a hot beverage prior to making a sales pitch. The Amygdala The amygdala is an almond-shaped bundle of neurones found in each cerebral hemisphere about an inch in from each of your ears (see Figure 11.8). It is an important part of the limbic system – a group of components which lies deep within the brain (part of the subcortex) and is concerned with  Seeing Emotions in the Brain – the Neuroscience of Emotional Experience 297 Figure 11.8 The orbitofrontal cortex and limbic system of the human brain (together with other components of the limbic system). emotions. It has been known for a number of years that the limbic system and, in particular, the amygdala, is involved in emotions, since humans with damage to this area and animals that have been lesioned here show inappropriate emotional responses. Both humans and monkeys, who have damage to the amygdala, appear to be unable to recognise fear in the faces of others (Calder et al., 1996; Atkinson, 2007; Ray, 2013). Furthermore, they have profound problems with memory (Le- Doux, 2012; McGaugh, 2004; Toates, 2011). Brain scans of undamaged individuals have now con- firmed that the amygdala is active during the perception of emotional faces and particularly so when viewing fear (Morris et al., 1998; Ray, 2013). Interestingly, Blair et al. (1999) have demonstrated that, in addition to increased activation when viewing fear, PET scans also show an increased acti- vation of the amygdala when perceiving sad but not angry faces. Moreover, it is now known that the amygdala is involved in other emotional states such as aggression, sexual, maternal and ingestive (eating and drinking) behaviours and is also important in reward learning and motivation (Kenny, 2011; LeDoux, 2012). The amygdala has neural connections within the temporal lobe which allows for involve- ment both in emotional face perception and in emotional memories. Intriguingly, one case study of a woman with damage to the amygdala (‘SM’) found that, while she still understood the concept of fear, she could no longer feel it (Feinstein et al., 2011). Disturbingly, the researchers subjected SM to live snakes and spiders, took her on a tour of a haunted house and showed her a series of disturb- ing films. None of these evoked fear even though she reported that prior to her injury they would have done so. Fortunately for SM she was still able to experience other emotions, both positive and negative. What these findings tell us about the role of the amygdala is open to debate. Is the state of fear actually experienced in the amygdala or is this part of a neural circuit which allows for the experience? Moreover, does the emotional state cause increased activity in the amygdala or does 298 The Evolution of Emotion increased activity in the amygdala cause the emotional state that we feel? In either event, it is fasci- nating to note that the two are clearly related. The Orbitofrontal Cortex The cortex of the brain consists of a six-millimetre-thick convoluted sheet of neurones which forms the outer surface of the brain covering the structures below (the subcortex referred to above). The cortex is responsible for many of our higher functions such as language processing, reasoning and consciousness (Toates, 2011). Each part of the cortex is described neuranatomically by its position relative to the centre of the brain. The orbitofrontal cortex (OFC) consists of the outer covering of the brain just above the orbits of the eyes – hence the name. Just above the orbitofrontal cortex are other frontal lobe regions which consist of a large amount of cortex in each cerebral hemisphere that is involved in controlling behaviour (see Figures 11.7 and 11.8). The orbitofrontal cortex receives information from other regions of the cortex of the frontal lobes and from the sensory systems. It also has extensive communication with the limbic system below. In a sense, the orbitofrontal cortex may be said to be kept very much informed about what is going on in the outside world and what is going on internally with regard to planned behaviour. Furthermore, it is able to affect the activity of the limbic system and, in particular, the amygdala. It is not surprising then that it has been known for some time that the orbitofrontal cortex is, in some way, very much involved in emotion. In the words of Toates (2014): The OFC is then an integrator, which extracts signals corresponding to the holistic quality of events put into context. (51) Interesting, the left OFC is known to be involved in the processing of positive emotions while the right OFC processes negative ones (an example of lateralisation of function; Ray, 2013; see Box 11.4). Damage to the orbitofrontal cortex leads to profound changes in emotional response and to personality in general. In particular, those who survive such injury to the right side generally show signs of euphoria and irresponsibility (Berridge, 2003; Kringelbach and Rolls, 2004). In the case of this area of the brain, however, a neuroimaging technique (or a technique related to neuroimaging) has been used in a novel way to illustrate how the orbitofrontal cortex may be involved in emotional responses in a patient who died over a century ago. Phineas Gage – an Early Study of Serious Brain Injury One of the earliest documented cases of damage to the orbitofrontal cortex occurred in the middle of the nineteenth century and involved railway foreman Phineas Gage. Back in 1848, Phineas was working on one of the new railroads that was being constructed throughout North America at the time. One day he came across a large boulder which was lying in the area where the new track was to be laid. In order to remove this rock he drilled a hole and filled this with dynamite. He then took a large tamping iron to ram the dynamite into place. Unfortunately, a spark caused by friction of the iron against the rock ignited the dynamite, causing it to explode. The explosion sent the bar through Phineas’ left cheek and through the front of his brain, leaving via the top of his head and landing some 300 feet away. Neuropsychologist Antonio Damasio and his co-workers used a high-power computer to reconstruct the damage that must have occurred to the front of Phineas’ brain and were able to confirm that his orbitofrontal cortex would have been largely obliterated (Damasio et al., 1994; see also Ratiu et al., 2004).  Phineas Gage – an Early Study of Serious Brain Injury 299 There are two fascinating things that can be said about Phineas Gage following his acci- dent. The first is that he survived it. In fact, after briefly losing consciousness, he was able to walk to a wagon that was to take him to the doctor; the second is that, after recovering, he was a changed man. Whereas prior to the accident he was considered to be a serious and industrious man who was thoughtful and well respected, following it he became irritable, childish and thoughtless (Harlow, 1848; Ratiu et al., 2004). Figure 11.9 shows the position of the tamping iron as it passed through his skull. This was perhaps the first clinical evidence that quite a specific portion of the cortex is heavily involved in emotion and personality. A small number of cases similar to Phineas Gage’s (see Box 11.4) have subsequently been reported in which the orbitofrontal cortex has likewise been seriously damaged (the number is small because most people receiving such a serious injury would be unlikely to survive). In each of these, distinct changes in emotional response have also been observed (Carlson et al., 2000; Carlson and Birkett, 2016). The list of emotions affected is lengthy and includes problems of anxiety, apathy, ir- ritability, impulsivity and a general lack of thought for others. Such a large list makes it unlikely that the orbitofrontal cortex is specifically involved in one or two emotional states. It appears more likely that this area of the brain is involved in integrating and appreciating subtle social and emotional cues such that the ability to distinguish between trivial and important decisions becomes seriously impaired (Damasio, 2003; Carlson and Birkett, 2016). The findings with regard to the amygdala and the orbitofrontal cortex may be taken as evidence for the existence of an innate biological organisation of emotional processing. Since brain Figure 11.9 Computer reconstruction of passage of the tamping iron through the head of Phineas Gage. The rod destroyed much of his left frontal lobe, leading to profound changes in his personality and behaviour. 300 The Evolution of Emotion organisation is largely the outcome of selection pressures then evolutionary psychologists would argue that these findings support the notion of emotions being the product of evolution (LeDoux, 2012; Izard, 2009). The Chemistry of Emotions – Adrenalin, the Sport Commentator’s Hormone Although the brain (and nervous system in general) is very much the seat of human emotions, its ac- tivity is modified by the release of hormones from endocrine glands into the bloodstream. While the release of these hormones is very much controlled by the central nervous system, we should also bear in mind that these chemicals are taken by the bloodstream to the brain where they affect its activity. An example of this is the activity of the hormone that all self-respecting sports fans know about – adren- alin (also known as epinephrine). When challenging emotional events occur, the amygdala sends messages to the autonomic nervous system or ANS (the part of the nervous system which regulates the activity of the internal organs). The ANS, in turn, causes the release of adrenalin into the blood- stream from the adrenal glands just above the kidneys. This adrenalin is the ‘fight or flight’ chemical which prepares target organs such as skeletal muscles for action. So, when frightened or excited, a part of the brain causes the hormone adrenalin to be released – and this, in turn, prepares the body for the challenge. The question is, does the amygdala provide us with the feeling of anxiety, excitement and general readiness for action, or does the adrenalin that is ‘pumping away’ somehow cause these feelings? Or indeed does it work both ways? Once in the bloodstream adrenalin, in addition to affect- ing the heart, gut and muscles, also travels to the brain where there are a number of widely dispersed receptor sites that are affected by it. In the brain adrenalin has a number of effects – including, via its action in the temporal lobe, helping to strengthen memory formation and an effect on the amygdala (Carlson and Birkett, 2016; Toates, 2011). The amygdala sends neural fibres to higher centres in the cortex and receives feedback from these areas. This means that the exact cause of the fight or flight response and how we eventually perceive this activity is extremely difficult to disentangle. Box 11.4 Lateralisation – the Asymmetrically Emotional Brain Although the left and right cerebral hemispheres of the forebrain appear as structural mirror images of each other, functionally they are different in some respects. This functional difference is known as lateralisation. The study of lateralisation began in the middle of the nineteenth cen- tury when it was observed that, whereas damage to the right hemisphere usually has little effect on language abilities, damage to the left leads to quite profound linguistic deficits (Springer and Deutsch, 1998; Corballis, 2014; see also Chapter 10). Since this time, many claims have been made with regard to the differing functions of the two hemispheres. Following over 150 years of research, the most robust findings are that the left hemisphere is especially associated with the recognition and processing of language and the right plays a major role in emotions (Springer and Deutsch, 1998; Corballis, 2009). Although initial work on the involvement of the hemispheres in emotions suggested that this was the sole domain of the right side, more recent research has demonstrated that the left hemisphere also plays an important role.  The Chemistry of Emotions – Adrenalin, the Sport Commentator’s Hormone 301 Box 11.4 (cont.) Before discussing these findings it is necessary to understand something of the methodology employed by researchers interested in lateralisation. One way of testing how well the two hem- ispheres are able to recognise emotional expressions is by presenting visual representations of expressions to each hemisphere. This may sound quite complex but is, in fact, quite an easy ex- periment to perform. Primary visual input from each lateral field (i.e. the area of vision clearly to the left or right of centre when you look straight ahead) is projected only to the visual processing centres of the opposite cerebral hemisphere. This means that visual input from the left visual field is initially sent only to the right hemisphere, the reverse being true for the right visual field. So by presenting pictures to either lateral visual field and recording a person’s response, we can gain some insight into the workings of each hemisphere separately. Quite a speedy response is required since, given a little time, the two hemispheres will pass information back and forth between them (inter-hemispheric transfer) via a large bundle of neural fibres known as the corpus callosum. One way of using this ‘half visual’ field method is to present participants with a chimeric face consisting of a neutral half-face on the one side and an emotional one on the other side (see below). When presented with a pair of such chimeras, one above the other (one with the emo- tion on the left and one with the emotion on the right) and asked which face shows the greatest emotional intensity, a number of researchers have demonstrated that the one with the emotion on the left side is the most expressive (Levy et al., 1983; Springer and Deutsch, 1998; Watling et al., 2012). This suggests the right hemisphere is, indeed, superior at recognising expressed emotions. We might call this the right-hemisphere hypothesis for emotional processing. Some researchers, however, have suggested that, while the right hemisphere is better able to recognise negative emotions, the left hemisphere is superior when it comes to positive emotions (see e.g. Reuter-Lorenz and Davidson, 1981). This notion of a left hemisphere superiority for positive ex- pressions and a right-hemisphere superiority for negative ones is called the valence hypothesis and appears to contradict the right-hemisphere hypothesis. Workman, Peters and Taylor (2000; see also Workman et al., 2006; Taylor et al., 2012) have produced experimental evidence using a series of chimeric faces which suggests there may be some truth in both hypotheses. When pre- sented with six different expressive chimeras – happiness, sadness, surprise, disgust, fear and an- ger – they found that, superimposed onto an overall right-hemisphere advantage, there is a shift back to the left when viewing pro- as opposed to antisocial expressions. The pro- and antisocial Figure 11.10 Two chimeras showing fear. Which do you find the more intense expression, A or B? 302 The Evolution of Emotion Box 11.4 (cont.) way of grouping emotions is somewhat different from the positive and negative dichotomy that has traditionally been used. Workmans and his co-workers suggest that the fundamental differ- ence between the two hemispheres when involved in emotional processing lies in a pro-social/ approach/left hemisphere and an antisocial/withdraw/right hemisphere dichotomy. Just to complicate matters further, Richard Davidson and his co-workers at the University of Wisconsin have suggested that, although the right hemisphere is superior at recognising emo- tional stimuli, the left may be more involved in experiencing it (Davidson and Sutton, 1995). Clearly, the question of the lateralisation of emotions requires further research. In addition to adrenalin, other hormones are released during emotional states. Testosterone and cortisol, for example, are both related to stressful events in life and to memory formation (Carl- son and Birkett, 2016). Following a fight between two male mammals, for example, the loser will show reduced levels of circulating testosterone and elevated levels of cortisol – the reverse being the case for the victor (Toates, 2011). Cortisol and other related hormones (the corticosteroids) are believed to strengthen memory formation (McGaugh, 1992; Barsegyan et al., 2010), so an animal which has been defeated is unlikely to forget who the victor is and make the same mistake again. Evolutionists explain this effect on memory formation as part and parcel of the function of emo- tions – that is, hormones that are secreted might not only prepare us physically for events but may also ensure that positive and negative encounters are remembered, since they are likely to have had survival and reproductive consequences for our ancestors. Learning and Cultural Display Rules Can Modify Emotional Response Despite the move towards resolving the differences between cultural relativists and evolutionists by Paul Ekman (see Box 11.5), the notion of universal emotions is still a controversial one among many social scientists (LeDoux, 2012; Izard, 2009; Barrett, 2018). It is certainly the case that there are cultural differences in the use of facial expressions and in emotional responses to various stimuli. We all frequently hide or modify our true internal state when in public. In fact, just which emotions we should display in public, and to what extent, varies quite considerably between societies. In Japanese culture, for example, there is a general discouragement of the public display of any emotions other than happiness. Consequently, since Japanese people smile a great deal on the streets and rarely show an unhappy face, they may appear to outsiders to feel negative emotions less frequently than, say, Europeans or North Americans. The emotional expressions (and frequency and intensity there- of) that a particular culture permits are known as its display rules (Ekman et al., 1972). In this way how much emotional expression an individual demonstrates depends, in part, on the display rules of that individual’s culture. This does not mean that different cultures feel different levels of emotional range and intensity, but that how much they display in public is largely determined by their cultural norms. In fact there is some experimental evidence that, when on their own, individuals from cul- tures where negative emotions are frowned upon show these expressions as often as individuals from cultures where such emotional displays are acceptable. At least this has been shown for Japanese individuals as far as expressions of anxiety and disgust are concerned (Ekman et al., 1972).  Learning and Cultural Display Rules Can Modify Emotional Response 303 Box 11.5 Criticisms of the Universality of Emotions – Human Pigs and False Smiles While the notion that basic human emotional expressions are universal and therefore derived from a common evolutionary ancestor has gained a fair degree of support from psychologists over the last 30 years, it is not without its critics. Fridlund (1992), for example, argues that facial expressions are social tools that we use largely during communication rather than for showing our true feelings to others. If this is the case, then each society may have developed different ex- pressions to mean different things during normal communication. Smiling, for example, is some- times used to express sarcasm. Likewise, laughter, under the right circumstances, may be used as a threat. A more hard-line version of this argument is that emotions are products of society rather than of biology (see e.g. Averill, 1980; Harré, 1986). This is the social constructionist or SSSM view of ‘human nature’ (see Chapters 1 and 14). James Averill, for example, has described an emotional state that is observed among the Gururumba who live in the highlands of New Guinea which is called ‘being a wild pig’. In this state villagers spend some time running wild like an undomesticated pig. They may be violent and steal things – although they rarely really hurt any- one or take anything of real value. After a while the ‘wild pig’ returns to a normal village activity and life continues as before with no recriminations. Since this wild pig state is unknown in other cultures, Averill uses this example to support his view that most emotional reactions are socially constructed (Averill, 1980; LeDoux, 2012). If evolutionary psychologists are to claim that human emotions are universal then they will need to address such arguments. One way of dealing with such examples is Ekman’s proposal that we should distinguish between basic expressions common to all cultures and other bodily movements that are learned and may incorporate these fundamental expressions. In this way, the culture-specific expressions can be placed at a level above the basic universal emotions (Ekman, 1980; 1992). This means that, in Ekman’s view, much of the disagreement may be more apparent than real since social constructionists are focusing at the level of learned cultural differences while the basic emotion theorists are focusing at a more basic level of innate responses. Ekman further concedes that basic expressions can be consciously modified to take on different mean- ings under different social circumstances (Ekman and Cordaro, 2011; see also ‘display rules’ above). One way to envisage this is, although there are named primary colours, there is also potentially an infinite range of mixtures of these. We should also bear in mind that, as in virtually all human responses, emotional responses can be modified by personal experience. While certain animals that might have posed a danger to our ancestors tend to be those about which we are most likely to develop a phobia, such as snakes and spiders (both of which are poisonous in many parts of the world), whether or not we develop such a phobia depends very much on our early experience with them. Being frightened by a spider or a snake as a young child may lead to the full-blown anxious fear that we call a phobia; however, being reassured by an adult that they are unlikely to cause harm may mean that a child grows up without developing the phobia (Field and Field, 2013; Field and Workman, 2008). An acquired response such as a fear of dogs following being bitten is called a conditioned emotional response. In many cases, since the conditioned response is learned, the learning may be reversed by classical conditioning whereby positive experiences are paired with the phobic animal. Having some plastici- 304 The Evolution of Emotion Figure 11.11 Cross-culturally, when people smile, they use exactly the same muscles in exactly the same way, and we all recognise this as a sign of friendship. Despite this, the frequency of smiling varies somewhat between cultures due to ‘display rules’. part of the world to another. The fact, however, that classical conditioning is frequently unsuccessful as a treatment for snake and spider phobias supports the hypothesis that these responses are partly inherited because of the threat to our ancestors. This notion of being born with a propensity to acquire a phobia about certain animals or objects rather than others has been called preparedness theory (Seligman, 1970; Buck, 1988; Ohman and Mineka, 2001). Another area where humans demonstrate plasticity of emotional response lies in what we find physically attractive. Here there is a great deal of scope for modification during development. In some cultures, for example, scars or tattoos are considered very attractive bodily adornments while in others they may be seen as ugly disfigurements (Carlson et al., 2000). Additionally, what a given culture finds attractive or ugly may change quite rapidly over time and may even differ between different sub-sections of a society. In Western culture today, for example, the emotional response to tattoos has recently changed, at least for younger members of society, who frequently regard them as ‘cool’ and sophisticated rather than as blemishes. So while emotions may be universal in the sense that all cultures appear to have the same basic range of internal states and external signals, there is clearly a fair degree of malleability built into the level of response to external stimuli in our species (Barrett, 2018). If we are to accept that emotions are adaptations then this raises the question of what precise functions they might serve. Proposed Functional Explanations for Specific Emotional States So far we have suggested that our current repertoire of emotions arose from the selection pressures  The Function of Specific Emotions 305 different cultures use the same basic emotional expressions under similar circumstances; our primate relatives use similar facial expressions under similar circumstances; humans have quite specific neural hardware devoted to recognising and processing emotions. There is, however, another way in which such findings can be explained without evoking natu- ral selection: that is, emotions may have come about as epiphenomena of evolutionary processes. Recall from Chapter 2 that this means they might be the by-products of other adaptations without adaptive significance. Randolph Nesse (1990; 2011; 2019) sees this explanation as highly unlikely since emotions are not only shared by people of different cultures, they also have clear fitness reper- cussions as we have seen. Clearly, becoming emotionally attached to partners and to offspring are generally prerequisites to passing on our genes. Likewise, being able to react emotionally to signals of danger would have consequences for gene replication. Indeed, people with serious emotional problems are frequently unable to look after themselves, let alone form stable attachments and rear offspring (see Chapter 12). Such findings suggest the epiphenomenon explanation is less likely than the adaptation one. The Function of Specific Emotions Nesse, following on from previous evolutionists, attempted to specify the ‘situations and selective forces that have shaped each emotion’ (Nesse, 1990, 269). In a similar vein, Barbara Fredrickson of the University of Michigan and (as we saw earlier) Paul Ekman of the University of California have also brought an evolutionary perspective to bear on human emotions (see e.g. Fredrickson, 1998; Ekman, 1994; 1998). Although there is much overlap, there are also differences in the approaches of the three evolutionists. The following discussion, which draws heavily on the work of Nesse, Fre- drickson and Ekman, considers the possible adaptive function of the core ‘positive’ and ‘negative’ emotions: fear, anger and sadness on the one hand and love and happiness on the other. We begin with negative emotional states. Negative Core Emotions – Fear, Anger and Sadness Negative emotions are believed to have evolved in order to allow us to respond appropriately to aversive stimuli. Negative emotions differ in fundamental ways from positive ones in that the for- mer appear to be both more abundant and more specific (Fredrickson, 1998; 2004). Fear and anger, for example, are generally related to very specific events, whereas happiness and love are more ephemeral and may be considered to be more general. Nesse has suggested this greater specificity for negative emotions has come about because there is a larger number of different types of threats than there are types of opportunities. Another difference may be thought of as an asymmetry of the consequences of not responding to positive and negative circumstances. Not responding to a life-threatening situation might have had dire consequences for our ancestors. Not responding to opportunities would have had less serious consequences. Ignoring a mating opportunity might allow for other opportunities at a later date. Ignoring a charging rhino does not allow for any future oppor- tunities. Today a number of evolutionists have argued that selection pressures for negative emotional responses would have been both stronger and more specific than those for positive ones (Pratto and John, 1991; Fredrickson, 1998; 2006). If there is one core emotion that has clear survival implications it must be fear. People who have no fear do not make for good ancestors. Ekman (1994; 1998) sees fear as one of the 306 The Evolution of Emotion fundamental emotions. Nesse, however, sees a number of sub-types of fear, each of which, he ar- gues, would have situation-specific ways of augmenting fitness. Panic and agoraphobia, for exam- ple, may be seen as adaptations which prepare the body, both physiologically and psychologically, for escape. Blood circulation is re-routed to the muscles, and the mind becomes highly focused on finding escape routes. A number of evolutionists have argued that ‘negative’ emotions such as fear and anger generally serve to narrow the focus of attention and increase vigilance (see Fredrickson, 1998). Anyone who has ever felt either intense fear or complete rage will be aware that, once we are attending to the object of such negative emotions, we are not easily distracted from them. Other evolutionists have considered that negative emotions are related to urges to take quite specific action. Such urges have been labelled specific action tendencies (Frijda, 1986; La- zarus, 1991; Tooby and Cosmides, 1990b). Whereas fear is manifested by the urge to retreat, anger is clearly related to the urge to attack and injure. In either case the tendency to take action is quite specific. But how does sadness fit in with this idea? Unlike fear and anger, sadness is a negative emotion for which it is difficult to imagine a ‘specific action tendency’. What is it that people do when they are feeling sad? It might be argued that sadness creates ‘the urge to withdraw from ac- tion’ (Fredrickson, 1998, 303). It has also been argued that sadness is a form of self-punishment that motivates us towards protecting children and other loved ones (Wright, 1994). In either event surely we can’t label these as specific action tendencies? Perhaps, as both Ekman and Fredrickson have suggested, we should not anticipate all emotions fitting a single, general-purpose model but in- stead we should consider separate theories for separate emotions (Ekman, 1994; Fredrickson, 1998; 2001). Even some of the proponents of the specific action tendency model have noted its limitations for some emotional states (see e.g. Lazarus, 1991). It may be difficult to pin sadness down to a specific action tendency but our problems with this emotion do not end there. How people regard the state that we call sadness is also more difficult to pin down cross-culturally than fear and anger. American anthropologist Robert Levy has even reported one culture – the Tahitians – where, he argues, the people have neither the concept of sad- ness nor even a word to describe it. Interestingly, despite lacking the term of sadness, the Tahitians are clearly capable of feeling this emotion. When rejected by a lover, for example, they take on the appearance of being sad and frequently become lethargic in the way that we would recognise as sad- ness. They consider such a state to be a form of illness, however, which is unrelated to the rejection (Levy, reported in Ekman, 1998). This suggests that not having a concept of an emotion does not necessarily mean that such a state is alien to a culture. At this point it is worth flagging up another problem with the concept of sadness, that is, at what point do we consider the state of sadness to have developed into the more long-term condition of depression? This issue (along with the negative emotion of anxiety) will be considered when we address mental illness in the next chapter. Although negative emotions are often viewed as adaptive in that they help us to deal im- mediately with adverse events, one curious aspect of the state of anger that Nesse has highlighted is that it often involves spiteful threats or acts which may incur a cost to the actor. This is particularly the case when the target of the anger is a friend who has let us down. To put it in the language of Robert Trivers, we may feel incensed when anticipated acts of reciprocation fail to materialise (see Chapter 8). Nesse sees this form of anger as a problem for evolutionary theories of behaviour since it may lead to costly and apparently irrational behaviour. Under such circumstances, as Nesse puts it, ‘How can anger possibly be adaptive? Why not just ignore the person who will not cooperate and look instead for a different reciprocity partner?’ (Nesse, 1990, 277). The answer Nesse suggests is that such anger, paradoxically, might, in the long run, be rational. Anger directed towards friends who have treated us badly might signal to them that a defection has been detected and that this ‘will  The Function of Specific Emotions 307 not be tolerated’. This behaviour might persuade the defector to make amends or, failing this, it will at least demonstrate that the target is not open to further acts of exploitation (see Chapter 8). Such an explanation is a little speculative, but without having this form of outrage in our repertoire people would certainly be easy prey for exploitative ‘friends’. Incidentally, Nesse (2019) also suggests the negative emotions of guilt and ‘self-punishment’ have evolved partly in order to restore a relation- ship following a defection. Thankfully, for the most part, friendly relationships promote positive emotional states. Positive Emotions – Love and Happiness Most of the theoretical and empirical work on emotions has concentrated on the negative emotions. Barbara Fredrickson (1998) thinks there are three main reasons for this bias – that is, positive emotions are fewer and less differentiated than negative ones; do not generally create problems for people; make for less precise prototypes than negative ones. In contrast to some evolutionists, Fredrickson considers that positive emotions may be the product of quite strong selection pressures. Developing a theme first introduced by Derryberry and Tucker (1994), she turns the narrowing of focus argument for negative emotions on its head and suggests that positive emotions serve to expand an individual’s attentional focus, knowledge and general health. Fredrickson calls this the ‘broaden-and-build theory’ of positive emotions (Fredrickson, 1998; 2001; 2004; 2013). Fredrickson considers four basic emotional states: joy, interest, contentment and love (see also Ekman, 1992). The first three of these may be seen as components of happiness but Fredrickson considers these to be sufficiently distinct to merit individual consideration. Joy is generally associated with safe and familiar contexts and frequently with the achieve- ment of goals (Izard, 1977). To Fredrickson, joy embodies the urge to be playful. Engaging in play, as ethologists have long argued, promotes the development of both physical and intellectual skills (Fagen, 1981; see also Chapter 8). It also enables you to find out about the various strengths and weaknesses of other members of your social group relative to your own (Fagen, 1981). As Fre- drickson (2004) states joy ‘creates the urge to play, push the limits and be creative; urges evident not only in social and physical behaviour, but also in intellectual and artistic behaviour’ (1369). In this way the playful behaviour that is the outcome of feeling joyful may serve long-term social and intellectual functions. Interest, the main emotion of our ‘emotionless’ Mr Spock, is a state that all mentally healthy people feel every day of their lives. Without it we would be unlikely to engage in explora- tion and thereby increase our knowledge of the world. In fact it is almost impossible to conceive of life without ‘interest’. Some experts are unconvinced that interest is a basic emotion (Lazarus, 1991). But as Fredrickson points out, interest is more than just attending to something in a detached way – it involves an urge that is rewarding and pleasurable. Again, like joy, interest tends to have long-lasting intellectual consequences and is likely to broaden our ‘mindset’ (Fredrickson, 1998; 2006; 2013; see also Johnson et al., 2010). Contentment is generally seen as a low arousal positive state. So does this positive state also fulfil Fredrickson’s model of expanding an individual’s mindset? If contentment involves a desire to become inactive, then such an argument is less obviously applicable when compared to joy and interest. Fredrickson (2004) argues, however, that contentment is a state which ‘creates the 308 The Evolution of Emotion urge to sit back and savour current life circumstances, and integrate these circumstances into new views of self and of the world’ (1369) and that this, in turn, increases receptiveness. This is a slightly more convoluted argument than for joy and interest, but again it does fit in with her main thrust of broadening rather than narrowing perspectives. Love is quite a vague term used to describe a number of emotionally positive states that involve being strongly attached to another person. Clearly, we don’t love our mother or our children in the same way that we love our lover – but all of these relationships/states share the urge to be close to the target of our affections and a feeling of pleasure when in their company. How well do such feelings fit in with Fredrickson’s model of broadening a person’s mindset? Fredrickson (1998) sees love and the various positive emotions associated with it as helping to ‘build and solidify an individ- ual’s social resources’ (306). Such social resources might be drawn upon later. This implies that love may play a role in the development of reciprocal altruism – a not unreasonable assumption. Clearly, if love has arisen via selection processes, then it must have affected inclusive fitness. Reciprocal acts that seal a friendship may be a part of this, but surely a more direct route for affecting fitness would be via love’s effects on mates and family. Trivers certainly sees the various states of love as means of helping to increase our inclusive fitness (Trivers, 1985). Passionate love is an obvious state which is likely to boost our direct fitness (provided that love is reciprocated, of course), whereas love of family members and of other relatives puts one in a psychological state that is likely to boost both direct and indirect fitness (see Chapters 2 and 7). In Fredrickson’s model, positive emotions have been shaped by selection pressures, not because they allow for immediate life-preserving responses but because opening people up to new experiences puts them in a mental state to build for the future. In this way positive emotions may be seen as adaptations since ‘[T]hose of our ancestors who succumbed to the urges sparked by positive emotions – to play, explore and so on – would have by consequence accrued more personal resourc- es’ (Fredrickson, 2004, 1369). This is an attractive idea, but is there any empirical evidence to support it? Fredrickson cites two indirect pieces of evidence to support her theory. First, there is some evidence that people with bipolar depression (‘manic depression’; see Chapter 12) are particularly creative during their manic (extremely happy) phase (Jamison, 1993; 2011); and second, lab-based studies have demon- strated that, when a positive emotional state is induced into normal participants, their attentional focus may be broadened (Derryberry and Tucker, 1994, cited in Fredrickson, 1998). An example of this was when Fredrickson and her co-worker Branigan showed participants film clips designed to facilitate either positive (joy or contentment) or negative (fear or anger) emotional states and then asked them to list what they would like to do right now (up to 20 things). They found that partici- pants in the two positive conditions (joy and contentment) identified significantly more things they would like to do than those in the two negative conditions (fear and anger) or in a neutral condition. Fredrickson and Branigan claim that this is a clear way of demonstrating that inducing these positive emotional states led to an immediate broadening of a participant’s mindset. In recent years Fredrickson has extended her ideas on the ‘broaden-and-build’ theory of positive emotions to develop what she calls the ‘upward spiral theory of lifestyle change’ as a means to understand how positive emotions can improve a person’s future health-related behaviours (Fre- drickson and Joiner, 2018). Fredrickson, alongside her co-worker Thomas Joiner, has illustrated this upward spiral theory with Figure 11.12. The idea here is, just as depressed people can enter a downward spiral where negative emo- tions both characterise and promote negative mood, the spiral theory of lifestyle change explores the opposite process. More specifically, in the inner loop of the spiral model, as people have positive  Does the Theory of Universal Human Emotions Stand Up to Scrutiny? 309 Built resources: Biological & psychological Positive affect during health behaviours Engagement in Non-conscious health behaviours motives for health behaviours Figure 11.12 Model of upward spiral theory of lifestyle change. further positive behaviours. The outer loop demonstrates how these behaviours and states of mind are supported by building biological and psychological resources. An example of a biological re- source is improved heart rate, whereas an example of a psychological resource would be prioritising positivity such as increases in the concept of positive purpose in life. Note that the outer loop feeds into and supports the inner loop. According to Fredrickson, the ability to enter into an upward spiral is part and parcel of human adaptations to recover from long-term negative emotional states. Like Barbara Fredrickson, Randolph Nesse also considers positive emotions as important adaptations. Recently, however, he has modified his view of the functions of emotional states. As we have seen some evolutionists perceive specific emotional states as having quite specific functions. Nesse suggests, however, that while emotions did evolve to solve ancient recurrent challenges, rath- er than specifying such functions: Emotions make more sense when viewed as special modes of operation that increase abil- ity to cope with certain situations. (Nesse, 2019, 53) This means that, while we share emotional states with other species and with people from distant cultures, a given emotional state can have a number of functions and we need to consider the situa- tional context in order to understand such functions. This is as true for positive emotions as it is for negative ones. We may feel happy when a loved one shares a success with us. But we can also feel happy when we see a loathed one fail. Increasingly, during the twenty-first century evolutionists have begun to consider the impor- tance attached to positive emotions and they have done so by drawing on evolutionary theories that were developed to help explain pro-social behaviour during the latter years of the twentieth century. Does the Theory of Universal Human Emotions Stand Up to Scrutiny? As we have seen, in recent years evolutionary psychologists have begun to propose functional expla- nations for common human emotional states. In the case of negative emotions such as fear and an- 310 The Evolution of Emotion For positive emotions, it has been proposed that the feelings of love, joy, interest and contentment allow for the build-up of knowledge, relationships and resources. It has also been suggested that such emotions (along with negative ones such as anger and guilt) may have arisen as a part of the evolution of altruistic behaviour which is ultimately related to boosting inclusive fitness. Some might argue that such ideas are currently quite speculative. We should be aware, however, that it is the specifics of such arguments that are speculative rather than the general argu- ment that emotions are adaptations. Very few would argue today that selection pressures played no role in the origins of human emotions. One of the problems with the idea of specific action tenden- cies being related to specific social circumstances, however, is that we frequently find ourselves in a state of mixed emotions (Nesse, 2019). When insulted and challenged by an aggressive individual we are likely to feel anger, fear and anxiety in varying measures. Also, we should bear in mind the fact that different emotional states can have the same behavioural outcome. Crying, for example, can occur during extreme happiness as well as sadness (LeDoux, 1996; 2012). Moreover, as some cog- nitivists have asked, if these emotions really are universal then why is there disagreement over their precise number and nature (Ortony and Turner, 1990)? Indeed, a number of psychologists see emo- tions as involving higher cognitive appraisals rather than simply as hard-wired universal responses. To be fair to them, ‘basic emotion theorists’ such as Ekman are aware of all of these potential problems and have themselves accepted that cultural and cognitive factors can and do modify emotional responses (see Box 11.5). Ekman, as we saw earlier, now sees each of these basic emotions as a ‘family’. This means that when people experience an emotional category such as an- ger, there are shared distinctive signals (e.g. a facial expression) and similar physiological changes accompanied by thoughts and memories (Ekman and Cordaro, 2011). Furthermore, as LeDoux has pointed out, much of the debate concerning differences between the basic emotion lists of different researchers may be more apparent than real. Different terms may be used by separate researchers to describe the same emotional categories – joy and happiness, for example. Also, claiming that there are certain emotions that are common to all people does not deny that an individual can have more than one at the same time. Finally, in their defence, the evolutionists can now point to the evidence that homologous areas of the brain in ourselves and other species deal with fundamentally the same emotions. Such findings are difficult to explain without recourse to an evolutionary explanation, lending support to the argument for there being an innate biological organisation of emotions. An example of this is the cross-species involvement of the amygdala in fear reactions (LeDoux, 2012). Box 11.6 Nesse’s Proposed ‘Phylogeny of Emotions’ Strongly influenced by Darwin’s ideas on the evolution of emotions, in 2004 Randolph Nesse proposed what we might call an evolutionary tree of emotions (i.e. its phylogeny). The sug- gestion here is that ancient organisms began with arousal that evolved to deal with threats and opportunities. Later on in evolutionary history these became more differentiated in order to deal with adaptive challenges for each species. This eventually led to complex socially evoked emo- tional states in our species – such as romantic love, pride and shame. Note that, as Nesse has pointed out, the ‘imaginary tree illustrates the evolution of emotions, with interwoven boughs of different but overlapping emotions’ (Nesse, 2019, 54). It is not a nice neat package that some evolutionists might conceive of.  Are All Emotions Adaptations? 311 Box 11.6 (cont.) Figure 11.13 Nesse’s proposed ‘phylog- eny of emotions’. friendship pride shame anger, grief guilt kin status all socia status love ies ies all grief, social love l jealousy kin kin e at m repro m at n ductio acquisitive e ctio n pleasure rep rodu sadness ty xie ho an physical ma loss pe teri pleasure al pain phys ical e damag desire fear OPPORTUNITY THREAT (PROMOTION) (PREVENTION) excitement apprehension arousal Are All Emotions Adaptations? If we accept that some emotions are universal and have arisen from selection pressures then does this mean that we have to accept that all emotions are adaptations? We saw earlier how Randolph Nesse has argued that the epiphenomenon explanation is unlikely for the core emotions but this does not mean that we can dismiss it for all forms of emotional experience. The great sadness that is felt when a loved one dies might, as some have suggested, be adaptive in that it makes us withdraw from action and conserve energy at appropriate times such as during a famine, but bereavement may also be an emergent property of having an emotional brain. It might be that bereavement serves no adap- tive function but is simply the price we pay for having the positive emotions associated with love and attachment. This might be likened to the withdrawal symptoms people suffer from when a drug is withdrawn. If this is the case then it is also possible that some other negative emotions are not adaptive in themselves but are the result of the removal of the source of positive emotion (and vice versa). Determining which emotional states are adaptations and which are emergent properties will be a very difficult task for evolutionary psychologists to deal with. At least we can see that having focused on cognitive processes for so long, evolutionary psychologists are finally beginning to turn their attention to what drives these processes – emotions. 312 The Evolution of Emotion Summary In 1872 Darwin published The Expression of the Emotions in Man and Animals. In this ground- breaking book he argued that there are a number of emotional expressions which are innate and common to all cultures – universal emotions. Such expressions include sadness, anger, surprise and enjoyment. Although Darwin backed his theory of the universality of emotional expression with a great deal of personal observation, most twentieth-century social scientists disputed this claim, adhering instead to the notion that each society develops its own range of expressions. During the latter years of the twentieth century, however, evidence accumulated which supported Darwin’s contention. The universality of human emotions is supported by three forms of evidence. Comparison with other primates suggests a common evolutionary ancestor; cross-cultural studies suggest that dif- ferent cultures recognise and experience the same basic emotions; and certain areas of the human forebrain appear to be particularly associated with emotional states. Specifically, the amygdala is highly active during the state of fear, and an area of the cortex, the orbitofrontal, is believed to be involved in the appreciation of social and emotional cues in others. Two further areas, the anterior cingulate cortex and the insular cortex, are also heavily involved in emotional processing and are associated with states such as sadness and anger. These findings suggest an evolved neural sub- strate for emotional processing. Alongside Darwin, Sigmund Freud and William James also considered emotional states to be the products of evolution. Darwin proposed three principles around which emotions are based. These are (1) serviceable associated habits – a specific emotional state will predictably lead to a specific expression and posture; (2) antithesis – positive and negative emotions occur in paired opposites; and (3) direct action of the excited nervous system on the body independently of will – facial expressions and body postures related to emotions occur without conscious effort and provide cues that allow others to have insight into our internal state. Freud suggested that much of human behaviour is driven by the pursuit of pleasure and the avoidance of pain. James proposed that emotions are the result of the brain monitoring the state of the body and then responding with an emotional state, rather than the reverse. A number of social scientists have been critical of the notion that human emotions are universal. Some cultural relativists have proposed that emotions are the products of culture rather than bi- ologically evolved states. This social constructionist view of emotions is based on the fact that in some societies, there are apparently complex emotional states that are not found in others. Evolutionists such as Paul Ekman counter these claims by proposing that we should distinguish between basic emotions common to all people and culture-specific ones which involve putting these emotions together in ways that each culture has learned. Ekman also claims that, although all peoples experience a similar range of emotions, the expressions that a person shows in public may be determined by the ‘display rules’ of that culture. In this way, in comparison to Westerners, individuals from the Far East may be dissuaded from exhibiting sadness or anger in public, but they may show these expressions when alone. Evolutionists such as Randolph Nesse, Barbara Fredrickson and Paul Ekman have examined the argument that there are specific functions for various emotional states. Negative states such as fear and anger may have evolved in order to place people in the correct psychological and  Further Reading 313 physiological state to deal with aversive circumstances. These internal states may make likely appropriate behavioural responses, which have been called specific action tendencies. Positive emotions such as love and the components of happiness have received less attention than negative ones. Fredrickson and Nesse, however, have both suggested that positive emotions might serve the function of placing us in the appropriate psychological state to help build up social relationships. Nesse has developed this argument in relating it to kin altruism and reciprocation, while Fredrick- son has proposed that, in contrast to negative emotions, which narrow attention, positive emotions serve to ‘broaden our mindset’. Questions 1. Martin Seligman has argued that we are biologically prepared to develop phobias to some animals such as spiders and snakes due to their posing a danger to our ancestors – i.e. ‘preparedness theo- ry’. Make a list of the strengths and the limitations of this theory. How might we go about testing the preparedness theory of phobias? 2. List the different ways in which the term ‘love’ is used to describe quite different feelings in our species. In what ways might each of these examples of strong feelings ultimately be related to inclusive fitness? 3. Does human romantic love differ fundamentally from animal sexual imprinting? 4. What does the case of Phineas Gage tell us about the foundations of human emotional states? This case is often presented to demonstrate the materialist nature of internal emotional states. What does this mean, and how might it be criticised? 5. Nesse has suggested that negative emotions can be good for us in the long run. In the case of ‘WS’, following brain damage, she reported that she was no longer able to experience fear. As a thought experiment, if you were offered a pill that removed fear from your emotional repertoire, would you swallow it? If not, why not? Further Reading Barrett, L. F. (2018). How Emotions Are Made: The Secret Life of the Brain. New York: Houghton-Mifflin- Harcourt. An up-to-date account of one neuroscientist’s view of how emotions operate and how this comes about. Detailed but quite lucid and accessible. Considers brain, body and culture. Note Barrett is critical of the hypothesis that we share a number of basic emotional families or states. Damasio, A. B. (2003). Looking for Spinoza: Joy, Sorrow and the Feeling Brain. Fort Worth, TX: Harcourt Brace College Publishers. Discusses the relationships between brain and emotional states and presents these in a way that a non-specialist reader can digest. Darwin, C. (1872/1998). The Expression of the Emotions in Man and Animals (3rd ed.), with Introduction and Afterword by Paul Ekman. London: HarperCollins. Darwin’s original and lucid account of the relationship between evolution and emotions brought up to date by the incorporation of a number of commentary boxes by Paul Ekman. 314 The Evolution of Emotion Nesse, R. M. (2019). Good Reasons for Feeling Bad: Insights from the Frontier of Evolutionary Psychiatry. London: Allen Lane. Highly accessible account of the relationship between emotions and evolutionary pressures, from a founding figure in evolutionary psychiatry. A real page turner which explains why negative emotions can ultimately be good for us. Toates, F. M. (2020). Are evolutionary psychology and the neuroscience of motivation compatible? In L. Workman, W. Reader and J. H. Barkow (eds.). The Cambridge Handbook of Evolutionary Perspectives on Human Behavior (77–90). Cambridge: Cambridge University Press. An expert in motivation theory considers its relationship, with evolutionary psychology.