Lecture 14.docx

Lecture 14: The Marvels of the Vertebrate Brain, Especially the Expanded Human Brain – What’s so Special? Our Brain Can Do Much More of the Neural Processing Needed for the More Sophisticated Items in the Traditional Behavioral Framework Taxes Reflexes Fixed Action Patterns Learning Cognition Includ...

Lecture 14: The Marvels of the Vertebrate Brain, Especially the Expanded Human Brain – What’s so Special? Our Brain Can Do Much More of the Neural Processing Needed for the More Sophisticated Items in the Traditional Behavioral Framework Taxes Reflexes Fixed Action Patterns Learning Cognition Including something we have not dealt with yet, Emotions, but depending on how we think of emotions they can involve moderate levels of neural processing (achievable with a fish brain) or very high degrees of neural processing (achievable only with a human brain). Theories of Emotion Common Sense Stimulus + Subjective Fear Experience = Body Response (arousal) Places the feeling of fear before the reaction James-Lange Stimulus + Body Response (arousal) = Subjective Experience (fear) Places the reaction before feeling of fear Cannon-Bard Stimulus Body Response (arousal) OR Subjective Experience (fear) Schachter Stimulus + Body Response (arousal) + Interpretation = Subjective Experience Greater emphasis on cognition in appraising the situation This more cognitive approach has dominated the human emotions literature and casts doubt on the continuity with non-human animals (i.e., they have no feelings) Schachter & Singer (1962) Injected male college subjects with the hormone epinephrine (adrenaline), which triggers arousal Two groups: (1) the control group were warned of the arousing effects of the injection, and (2) the experimental group were told the injection would help their eyesight in the forthcoming test After the inject, subjects went to a waiting room with another person (an accomplice) who was acting either euphoric or angry Results: Depending on the behavior encountered experimental subjects were more likely to feel either happier or angrier compared to the control group. Conclusion: If subjects do not know the reason for the aroused emotional state, they search their environment for clues to interpret the emotion The Cannon-Bard theory differs in that both the response and the emotion are co-activated by the threat, which resolve some of the problems with the ‘humans are special’ theories E.g., I’m shaking and feeling afraid at the same time Stimulus (snarling dog) First Response (subcortical brain-activity) Second Response (ANS arousal changes in body – Conscious Fear) (1) it can explain why people with quadriplegia can still experience emotions despite not being able to physically respond to the threat, and (2) it can explain the commonalities in the behavior and the neural systems associated with particular emotional states in human and non-human vertebrates Panksepp’s Hierarchical Concept LeDoux’s Problem and Solution Objects to there being basic emotions that are innately programmed in subcortical circuits Rather, he is of the view that emotions are higher-order states instantiated by cortical circuits (i.e., to get away from emotions are subcortical and cognition is cortical – which smacks of Edinger’s ladder and McLean’s triune brain) He doesn’t disagree that there are survival circuits which have their origin in subcortical circuits, but these are connected to various other neural circuits that influence different aspects of behavior, rather than the emotions energizing the behavior LeDoux’s Integrated View It is the cortical part of the neural circuitry that generates the experience of emotions So, What are Emotions? Depending on the phenomenon being studied, the theories by Scachter, Panksepp, and LeDoux are all useful With LeDoux’s view, emotions, at least for humans, would be added to the traditional behavior framework in the following way Given the neural space given to cognition and the importance of cognition to human emotions, it is worth exploring how cognition is thought to work We can then use that understanding to revisit LeDoux’s logic in denying the existence of emotions in non-human animals So, What is Cognition? According to LeDoux, cognition involves the use of internal representations of things and events to formulate a behavioral response when confronted by an external stimulus How does this differ from Behaviorism? Behaviorist Model (Only study observable / external behavior) Stimulus in the environment Black box can’t be studied Response behavior Cognitive Model (Can Significantly study internal behavior) Input in the environment Mediational Process mental events Output behavior Note that cognitive science uses the tools of behaviorism (based on classical and operant conditioning paradigms) to force the animal to produce from which internal processes can be inferred Conditioning As conditioning is based on simple association, the occurrence of the conditioned stimulus (CS) should be in close temporal proximity to the unconditioned stimulus (US) and since it is the association to the US that is important, the identity of the CS is arbitrary This is nicely illustrated in Pavlov’s classical conditioning But these two assumptions are not always present John Garcia (1917-2013) Conditioned taste aversion (the Garcia effect) But these two assumptions are not always present: (1) The nausea can occur hours after the food was eaten (i.e., no temporal proximity between the CS and the US), and (2) the associations possible are not arbitrary Simple association cannot explain the Garcia effect, this suggests that the learning involve a cognitive dimension – representations in the brain are linked together By using sophisticated versions of both classical and operant conditioning methods, many cognitive processes have been identified and characterized But There is a Problem with LeDoux’s Logic The reason LeDoux uses for his view that there are no basic emotions (and by extension, non-human animals do not have emotions) is that you cannot infer common emotions from similarities in behavior – just because a ‘scared’ dog exhibits similar behavior to a ‘scared’ human, you cannot infer that the dog is experiencing fear as does the human But for cognition, LeDoux seems to have no problem in inferring common internal cognitive processes from similarities in behavior. Neither emotions nor cognitive processes are visible to the human experimenter, so what is the difference? He seems to have a particular dislike of anything that smacks of emotional feelings – he even denigrates the value of pleasure and pain as mechanisms for making associations Do the Similarities Matter? Using these common, cross species similarities in behavior, Berridge tracked down the neural substrates involved in rats Then using imaging, cognitive experiments, naturally occurring brain damage and afflictions like drug addition, Berridge confirmed that the same pleasure and pain circuits occur in mammals in general (including humans) But LeDoux would say that while you can ascribe feelings of pleasure to humans, you can’t to non-human animals. Problem: How do you know other people experience the same emotions as you do? You can ask them. But babies can’t speak, so by LeDoux’s logic they don’t have emotions. Also, lets not forget that once people are able to speak, they can lie, so how can you believe what they tell you? So following LeDoux’s reasoning to its logical extension leads us to the conclusion that the only animal on the planet that can experience emotions is me In most situations you know someone is happy or sad by their behavior – that is, you infer emotions from behavior not by ‘knowing’ the inner state of the other person So, I don’t buy LeDoux’s framework as an all-encompassing explanation of emotions