Week 8 Summary - Brain and Behaviour PDF

Week 8: Motivation Weekly Objective 1: Describe the different theories of motivation Motivation refers to factors that influence the initiation, direction, intensity and persistence of behaviour. A motive is a reason or purpose that may provide a single explanation for the occurrence of many differe...

Week 8: Motivation Weekly Objective 1: Describe the different theories of motivation Motivation refers to factors that influence the initiation, direction, intensity and persistence of behaviour. A motive is a reason or purpose that may provide a single explanation for the occurrence of many different behaviours. Motivation is thought of as an intervening variable – something that is used to explain the relationships between environmental stimuli and behavioural responses. Sources of Motivation Four factors can serve as sources of motivation: physiological, emotional, cognitive and social. The Instinct Doctrine and its Descendants Instinctive behaviours are automatic, involuntary behaviour patterns, originally called fixedaction patterns that are consistently triggered, or ‘released’ by particular stimuli. The original instinct doctrine provided a description, rather than an explanation, of behaviour and it failed to accommodate the role of learning in human behaviour. Today inborn tendencies are often referred to as modal action patterns because they can vary quite a bit among individuals and can be modified by experience. So, the contemporary view is that the behaviour of humans and other animals may be motivated by inborn tendencies, but it is not necessarily entirely ‘genetically determined’. It can be shaped, amplified, or suppressed by experience and other factors operating in individuals. · Psychologists who take the evolutionary approach suggest that the behavioural predispositions we see in humans and other animals today have evolved in part because they were adaptive for promoting individual survival. The Instinct Doctrine and Mate Selection The evolutionary approach suggests that inborn desires to pass on our genes cause women to focus on men’s ability to amass resources and men to focus on women’s reproductive capacity. Surveys have supported this hypothesis; however, mate selection patterns may reflect social and economic influences, not innate biological needs. Evolutionary theorists acknowledge the role of cultural forces and traditions in shaping behaviour, but emphasise the role of genetic predisposition and innate tendencies. They focus on the ultimate, longterm reasons behind what we do and the circumstances in which evolved predispositions are, or are not, expressed. Drive Reduction Theory Homeostasis is the tendency to keep physiological systems at a steady level, or equilibrium. According to drive reduction theory, an imbalance in homeostasis creates needs, biological requirements for wellbeing. The brain responds to needs by creating a psychological state called a drive, a feeling of arousal that prompts one to take action to restore balance and reduce the drive. Primary drives stem from inborn physiological needs, such as for food or water, that people do not have to learn. Secondary drives are learned through experience and they motivate us to act as if we have unmet basic needs. Arousal Theory Many behaviours cannot be explained by drive reduction theory, including curiositymotivated behaviours and those that are done just to cause an increase in physiological arousal, a general level of activation that is reflected in the state of several physiological systems. Arousal theory states that people are motivated to behave in ways to maintain or restore their optimal level of arousal, increasing arousal when it is too low and decreasing it when it is too high. In general, people perform and feel best when arousal is moderate. Optimal arousal levels vary from person to person. Incentive Theory According to incentive theory, behaviour is goal-directed; we behave in ways that allow us to get desirable incentives and avoid negative incentives. The value of a goal or incentive is influenced by biological, cognitive, and social factors. Motivation theorists distinguish between wanting and liking. Wanting is the process of being attracted to incentives, whereas liking is the immediate evaluation of how pleasurable a stimulus is experienced. These two systems appear to involve activity in different parts of the brain and involve different neurotransmitters. The wanting system can compel behaviour to a far greater extent than the liking system. Weekly Objective 2: Identify the control of hunger and eating Biological Signals for Hunger and Satiation Hunger is the state of wanting to eat; satiation is the satisfaction of hunger; satiety is the state of no longer wanting to eat. Signals from the Stomach Stomach cues affect eating, but they do not play a major role in the normal control of eating. The cues may operate mainly when people are very hungry or very full. In addition, the small intestine is lined with cells that detect the presence of nutrients and send neural signals to the brain about the need to eat. Signals from the Blood The brain constantly monitors the level of food nutrients absorbed into the blood from the stomach and the level of hormones released into the blood in response to nutrients and from stored fat. Short-term blood-borne signals that tell us when to start and stop eating are called satiety factors. One satiety factor comes from cholecystokinin (CCK), a neuropeptide that regulates meal size. Nutrients the brain monitors include glucose, the main form of sugar used by body cells. When glucose levels rise, the pancreas releases insulin, a hormone that most body cells need in order to use the glucose they receive. Insulin may amplify the brain’s response to CCK and it may also provide a satiety signal by acting directly on brain cells. The long-term regulation of fat stores involves a hormone called leptin. When leptin levels are high, hunger decreases, and vice versa. Leptin is not effective for treating obesity, severe overweight, because it appears that in most common cases the brain becomes less sensitive to leptin signals. Hunger and the Brain Regions of the hypothalamus detect and react to the blood’s signals about the need to eat. At least 20 neurotransmitters and neuromodulators, substances that modify the action of neurotransmitters, convey hunger or satiety signals to other parts of the hypothalamus and the brain. Activity in the ventromedial nucleus of the hypothalamus signals that there is no need to eat. Activity in the lateral hypothalamus stimulates eating. Initially, researchers thought that the combined activity in these areas maintained a homeostatic level or set point, based on food intake, body weight, and other factors. Once the set point was reached, normal animals would stop eating. This theory turned out to be too simplistic. More recent research indicates that other areas are also involved in the brain’s control of eating. The paraventricular nucleus in the hypothalamus also plays an important role. In addition, hunger and eating certain foods is related to the effects of various neurotransmitters on certain neurons in the brain. Neuropeptide Y stimulates increased eating of carbohydrates. · Serotonin suppresses carbohydrate intake. · Galanin motivates the eating of high-fat food and enterostatin reduces it. · Endocannabinoids stimulate eating in general. · Peptide YY3-36 causes a feeling of fullness and reduced food intake. • Flavour, Cultural Learning, and Food Selection Flavour, the combination of food’s taste and smell, can override a set point. More food will be eaten when a variety of flavours is offered. Another factor that can override set point is appetite, the motivation to seek food’s pleasures. Classical conditioning influences the appetite. The sight and aroma of food can elicit conditioned responses (the secretion of saliva, gastric juices, and insulin) that are associated with eating. These responses then increase appetite. Eating can also be influenced by specific hungers, desires for certain foods at certain times. These hungers may reflect biological needs for nutrients found in those foods. The taste and odour of food may become associated with its nutritional value. The food industry uses flavourings that trigger cravings in the absence of nutritional value. The role of learning is also seen when people start to eat in response to sights, sounds, and places which have been associated with eating in the past. People also learn social rules and cultural traditions that influence eating. Social cues tell people what and how much is appropriate to eat in certain social situations. The mere presence of others, even strangers, tends to increase food consumption. Eating in a culture is reflected in its food culture, which involves food and food selection, portion sizes, and speed of consumption. Unhealthy Eating Problems in the processes that regulate hunger and eating may cause eating disorders such as anorexia nervosa or bulimia, or can result in a level of food intake that leads to obesity. Obesity Obesity is a condition in which a person’s body-mass index (BMI) is greater than 30. (BMI is the person’s weight in kilograms divided by the square of the person’s height in metres. However, muscle weighs more than fat, so a very muscular person may have a high BMI without being overweight.). Obese people get more energy from food than their body metabolises, or ‘burns up’; the excess energy, measured in calories, is stored as fat. Obesity is associated with Type 2 diabetes, high blood pressure, certain cancers, liver and gall bladder disease, osteoarthritis, and increased risk of heart attack and stroke. Moreover, obesity is being blamed for increasing deaths each year and for a predicted shortening of life expectancy in the 21st century. Obesity appears to be on the rise among adults and children around the world. Reasons for the increase in obesity are unknown, but possible causes include big portion sizes at fast-food outlets, greater prevalence of high-fat foods, and less physical activity in work and recreation. Inadequate physical activity combined with overeating, especially of high-fat foods, has a lot to do with obesity. Not everyone who is inactive and eats a lot is obese and some obese people are very active, so other factors must also be involved. These include genetic predispositions, slow brain processing of satiety signals and viruses. Psychological explanations for obesity include factors such as learning and maladaptive reactions to stress. There are many treatment approaches to obesity. · The most radical is bariatric surgery, which involves restructuring the stomach and intestines so that less food energy is absorbed and stored. · Anti-obesity medications available or under development include one that prevents fat in foods from being digested, one that dissolves fat, and one that interferes with an enzyme that forms fat. · No single treatment is likely to work for everyone. To achieve the gradual weight loss that is most likely to last, people need to increase exercise, reduce food intake and change eating habits and attitudes toward food. · The ultimate remedy for the obesity epidemic is prevention. To accomplish that goal, parents and other caregivers must begin to promote exercise and healthy eating habits in their children from an early age. Anorexia Nervosa Anorexia nervosa is characterised by some combination of self-starvation, self-induced vomiting, and laxative use that results in weight loss to below 85 per cent of normal. Anorexic individuals are preoccupied with food, yet refuse to eat. Anorexic self-starvation causes serious, often irreversible physical damage. Between 4 and 30 per cent of people with anorexia die of starvation, biochemical imbalances, or suicide. Anorexia affects about 0.5 per cent of young females and .01 per cent of young males in Australia and New Zealand and is a growing problem in many other industrialised nations. About 95 per cent of those suffering from this disorder are young women. Anorexia is probably caused by a combination of factors including genetic predispositions, biochemical imbalances, social influences and psychological characteristics. Psychological factors include a perfectionist personality and an obsession with thinness. Treatments include drugs, hospitalisation, and psychotherapy. More effective methods and early intervention methods are still needed. Bulimia Nervosa Bulimia (or bulimia nervosa) involves eating huge amounts of food and then getting rid of the food through self-induced vomiting or strong laxatives. Bulimia also involves intense fear of being fat, but the person, who is often female, may be thin, normal weight, or even overweight. Bulimia and anorexia are separate disorders. Most with bulimia see their eating habits as problematic, whereas most with anorexia do not. Though bulimia is usually not life threatening, it can lead to dehydration, nutritional problems, intestinal damage, and dental problems. It is estimated to affect around 5 per cent of young people in Australia. Bulimia is probably caused by a combination of factors including perfectionism, low self-esteem, stress, a preoccupation with thinness, depression and other emotional problems. Biological factors may include defective satiety mechanisms. Treatments include individual or group therapy and, sometimes, antidepressant drugs. Weekly Objective 3: Explain human sexual behaviour Sex is not necessary for an individual’s survival. However, a strong desire for reproduction does help ensure the survival of a species. People show many different sexual scripts or patterns of behaviour that lead to sex. Focus on Research Methods: A survey of human sexual behaviour Human sexual behaviour was extensively studied by Alfred Kinsey using questionnaires in the 1940s and 1950s and by Masters and Johnson using laboratory observations of the human sexual-response cycle in the 1960s. However, the people involved in these studies were probably not representative of the adult population and so the results may not apply to people in general. More recent data from surveys in magazines are also flawed by non-random samples. What was the researchers’ question? Can researchers collect data that is more representative to describe people in general? In the early 1990s, researchers from the University of Chicago conducted the ‘National Health and Social Life Survey’, the first extensive survey of sexual behaviour in the US since Kinsey’s studies. • How did the researchers answer the question? This survey included important design features not used in other surveys of sexual behaviour. Participants were not volunteers. A sample of 3432 people, aged 18 to 59, was constructed to represent current US sociocultural diversity. Data were gathered in face-to-face interviews to assure that respondents understood and fully answered questions. Participants could answer some of the more sensitive questions by writing and sealing responses in an anonymous envelope. • What did the researchers find? · Most people had sex about once a week in monogamous relationships, and a third had sex a few times or not at all in the past year. · Males reported an average of six sexual partners in their lifetimes; women reported an average of two. · People in committed, monogamous relationships had the most frequent and satisfying sex. · The most common heterosexual sexual practice was penis–vagina intercourse. • What do the results mean? The results of the Chicago sex survey challenged popular culture and media images of sexuality in the US. It suggests that people in the US may be more sexually conservative than portrayed. • What do we still need to know? The Chicago survey did not ask about more controversial aspects of sexuality, such as pornography use, paedophilia (sexual attraction to children), and the role of sexual fetishes, such as shoes or other clothing in sexual activity. People in the US were the focus of this study; therefore, to know about people in the rest of the world, the Chicago team has continued to conduct interviews in the US and other countries. Other researchers focusing on gender differences in sexuality have found that men tend to desire sexual activity more than women do, and that women are more likely than men to associate sexuality with commitment in a relationship. Many questions are raised by studies like this. For example, when do people become interested in sex and why? How do people express their desires? How does learning modify the biological forces at the base of sexual motivation? • The Biology of Sex Masters and Johnson’s in-depth study of human sexuality and sexual arousal resulted in a description of the sexual response cycle, the pattern of physiological arousal during and after sexual activity. Although all sex hormones circulate in both males and females, some predominate in each sex. Females have more estrogens (for example, estradiol) and progestational hormones, or progestins (for example, progesterone), whereas males have more androgens (for example, testosterone). Sex hormones have two kinds of effects on the brain. Organisational effects are permanent changes that alter the brain’s response to hormones. These effects occur in areas described as sexually dimorphic around the time of birth when certain brain areas are sculpted into ‘male-like’ or ‘female-like’ patterns. Rising levels of hormones during puberty have activational effects, which are temporary behavioural changes that last only as long as the hormone level is activated. Social and Cultural Factors in Sexuality Sexual attitudes and behaviours are learned as part of the development of gender roles in a culture. A person’s learning history, cultural background, and perceptions of the world interact with a range of physiological processes to influence sexuality. Sexual Orientation Sexual orientation refers to the nature of a person’s enduring emotional, romantic, or sexual attraction to others. Most humans’ sexual orientation is heterosexuality, attraction to members of the opposite sex. Sexual attraction between members of the same sex is homosexuality (specifically, gay for men and lesbian for women). Attraction to both sexes is bisexuality. Attempts to alter the sexual orientation of homosexuals have usually been ineffective. Since homosexuals and bisexuals are often discriminated against, many hesitate to reveal their sexual orientation. Thus, it is difficult to estimate the relative mix of different sexual orientations. Studies that allow anonymous responses suggest that gay, lesbian, and bisexual people make up 21 per cent of the population of the US, Australia, Canada, and Western Europe. Weekly Objective 4: Outline the importance of achievement in goal setting People work partly due to extrinsic motivation, a desire for external rewards, such as money. They also work due to intrinsic motivation, a desire to attain internal satisfaction. Much behaviour is motivated by a desire for approval, admiration, and achievement, in other words, for esteem, from others and ourselves. Need for Achievement A desire for mastery or effectance is the motivation to behave competently. People with a high achievement motivation (need achievement) are motivated to master tasks and take great pride in doing so. Individual Differences People with a high need to achieve set challenging but realistic goals. They are interested in their work, actively seek success, take risks when necessary, are intensely satisfied when they succeed, and, if they have tried their best, are not too upset by failure. In contrast, people with low achievement needs seem to enjoy success because they have avoided failure. People with learning goals are concerned with getting better at something. They tend to be more persistent and less upset when they do not immediately perform well. People with performance goals are usually more concerned with how well they perform compared with others than they are about how to improve their performance. They tend to avoid challenges and quit in response to failure. Development of Achievement Motivation Achievement motivation tends to be learned in early childhood, largely from parents. Parents of children who scored high on tests of achievement motivation: encouraged children to try difficult tasks, especially new ones, · offered praise and other rewards for success, · encouraged children to find ways to succeed rather than letting them just complain about failure, and · prompted children to go on to the next, somewhat more difficult challenge. • Ideas about how people achieve differ from culture to culture. Subtle messages about a culture’s view of how achievement occurs often appear in books that children read and stories that they hear. Goal Setting and Achievement Motivation We set goals when we see a difference between how we want things to be and how things are now. Establishing a goal motivates us to engage in behaviours designed to reduce the discrepancy we have identified. The kinds of goals we set can influence the amount of effort, persistence, attention and planning we devote to a task. People work harder to achieve difficult goals. This assumes that the goal is valued and seen as realistic. Setting goals that are clear and specific tends to increase people’s motivation to persist at a task. Achievement and Success in the Workplace Workers tend to be more satisfied and productive if they are: · encouraged to participate in decision making, · given problems to solve on their own, · taught more than one skill, · given individual responsibility, and · given public recognition, not just money, for good performance. Allowing people to set and achieve clear goals is one way to increase both job performance and job satisfaction. Effective goals are those that are: · personally meaningful, · specific and concrete, and · set by the employees but encouraged and rewarded by management. Achievement and Wellbeing Wellbeing (or subjective wellbeing) is a combination of a cognitive judgement of satisfaction with life, the frequent experiencing of positive moods and emotions, and the relatively infrequent experiencing of unpleasant moods and emotions. Research supports the idea that people under extreme stress feel less happy than people in better circumstances, but effects of events on mood do not last as long as might be expected. People generally return to a baseline level of happiness, even after an extremely positive or negative event. Most people’s subjective wellbeing tends to be remarkably stable throughout their lives. Individual differences in happiness are more strongly associated with inherited personality characteristics than with environmental factors, such as money, popularity, or physical attractiveness. Close social ties, religious faith, and having adequate resources to allow progress toward one’s goals are important to happiness. Those who try to seek happiness by trying to acquire goods or status that they think they need, rather than appreciating life itself and what they do have, have a deficiency orientation and experience unhappiness and psychological problems. Relations and Conflicts among Motives Abraham Maslow proposed that human behaviour reflects a hierarchy of needs or motives. Needs at the lower levels must be at least partially satisfied before people can be motivated by higher-level goals. The five motives from bottom to top are: biological, such as the need for food, water, air, and sleep, · safety, such as the need to have a secure income and a safe place to live, · belongingness and love, the need to be part of groups and to have relationships, · esteem, the need to be respected as a useful, honourable individual, and · self-actualisation, fulfilling one’s fullest potential. • Maslow’s hierarchy has been called simplistic because it cannot explain extreme behaviours due to politics or moral causes, it does not account for the seeking of several needs at once, and it does not acknowledge that needs may differ across cultures. There may not be a single, universal hierarchy of needs. The existence, relatedness, growth (ERG) theory places needs into three categories: existence needs, such as for food and water, · relatedness needs for social interactions and attachments, and · growth needs, such as for developing one’s capabilities. • The ERG theory does not assume that needs must be satisfied in a particular order, but motivation to pursue them depends upon time and situation. Linkages: Conflicting motives and stress Motives that act at the same time complicate life and can create significant emotional arousal and other signs of stress. Conflicting motives can make a person more vulnerable to physical and psychological problems when there is no obvious right choice, when the conflicting motives have approximately equal strength, and when the choice can have serious consequences. There are four basic types of motivational conflicts. 1. Approach-approach conflicts exist when one must choose only one of two desirable activities. 2. Avoidance-avoidance conflicts force one to select from two unattractive choices. 3. Approach-avoidance conflicts occur when one activity has both attractive and unattractive features. 4. Multiple approach-avoidance conflicts involve a choice between two or more alternatives, each of which has both positive and negative features. These conflicts are the most difficult to resolve, partly because the features of each option are often difficult to compare. Opponent Processes, Motivation and Emotion According to opponent-process theory, any reaction to a stimulus is automatically followed by an opposite reaction, called the opponent process. After repeated exposure to the same stimulus, the initial reaction weakens, and the opponent process becomes quicker and stronger. For example, before a first skydiving jump, people usually experience terror, followed by intense relief when they reach ground. With more experience, though, the terror becomes mild anxiety and the relief becomes a sense of elation that may begin to appear during the jump.