Chapter 11

Evolution of Emotion

Emotions

• Evolutionarily selected adjustments to physiological, psychological, and behavioural parameters, allowing an organism to adaptively respond to threats and opportunities in the environment– Adapted from Nesse (1990)

Principle of Hedonism

• Seek pleasure– (Appetitive events)

• Avoid pain– (Aversive events)

• Consider emotional states in this context

Evolution and Emotions

• Selective forces

• Emotions

• Effect on inclusive fitness?

Three Hairy Men

Early Views on Emotion• Charles Darwin

– The Expression of the Emotions in Man and Animals (1872)– Each emotional state will have its own expression– Emotions occur in opposing pairs– Emotional reaction independent of will– Emotional state results in external expression of emotion

• William James– Internal, visceral state monitored by brain– Physiological response subsequently creates emotion

• Sigmund Freud– Understanding emotion central to understanding behaviour

Innateness of Emotions

• Cross-species comparisons• Similar expressions under

similar situations• Primate facial expression

as byproduct of vocalizations in particular emotional state (Andrew 1963)

http://webdrive.service.emory.edu/groups/research/chimpanzee-cognition/CCL/facs.htm

Later Reinterpretation

• Innate nature of emotion challenged

• Behaviorists

• Anthropologists (e.g., Bateson & Mead)

• Does each culture really develop its own unique emotional states?

Ekman & Friesen (1971)

• Emotions not culturally determined• Anger, disgust, fear, joy, sadness,

surprise– Other research suggests 5-8 basic

emotion types

• Blending of emotion types to create full range of expressions displayed

• Cross-cultural recognition of facial expression

Learning, Cultural Display Rules

• There are cultural differences in the use of facial expression and emotional response

• Issue of suppression/modification of display, rather than lack of emotion itself

• Individual learning influences emotional displays (e.g., specific phobias)– Observational learning– Preparedness towards certain fears

ToM and Emotional Display

• Adaptive value in knowing your own and others’ emotional states

• Sociality

• An aspect of Theory of Mind

• Displaying your emotional state gives others information; similarly, can gain information from observing others’

• Concealment and deception

• Frontal cortex– Weigh future

consequences of actions and plan accordingly

– Sociality

Amount of brain taken up by frontal association cortex.From: Kandel, Schwartz, Jessell (1991), p. 827

Neurology of Sociality

Frontal Cortex

• Two main regions:• Prefrontal association

cortex• Orbitofrontal cortex

(OFC)– Part of limbic association

cortex

– Direct connections with amygdala

orbitofrontalcortex

From: Kandel, Schwartz, Jessell (1991), p. 827, 306

Deficits with Medial Frontal Cortex Damage

• Mental state attributions

• Appropriate social behaviour

• Understanding high-level language and metaphor

• Positive or negative emotions

• Autistics show many of the same problems

Amygdala

• Part of limbic system– “Old” part of brain

• Activated by emotional displays– Facial expressions– Fear and threat

Orbitofrontal Cortex

• Lesion OFC– Normal aggressiveness

and emotional response reduced

– Reduction of chronic pain

– Socially inappropriate behaviour and humour

– Low empathy

– Poor social decision-making

• Electrical stimulation of OFC– Autonomic responses

– Increased blood pressure, pupil dilation, salivation, etc.

– Generalized arousal reaction

Orbitofrontal Cortex

• Combine mental state and emotional information

• Damage still allows cognitive understanding of social issues

• But, cognitive assessment can’t be put in emotional context

Endocrinology

• Besides neural role, endocrine glands

• Secrete hormones to bloodstream

• Affect target organs, including brain

• Is it the initial brain action that produces the emotion, or the subsequent effect of the hormone on body and brain systems?

Adrenalin• Stress -->• Amygdala -->• Activates autonomic nervous system -->• Adrenal glands -->• Release of adrenalin to bloodstream -->• Into brain -->• Receptor sites in temporal lobe and

amygdala -->• Enervation of higher cognitive areas

Function

• Core emotions

• Negative– Fear, anger, sadness

• Positive– Love, happiness

Negative Core Emotions

• Fear, anger, sadness• Appropriate response to aversive stimuli• Generally related to specific events

– Large number of particular types of threats– Consequences of wrong response to threat

worse than wrong response to opportunity

• Fear has obvious survival benefit– Particular subforms, e.g., panic, agoraphobia,

with specific responses

Specific Action Tendencies

• Fear --> urge to retreat

• Anger --> urge to attack/injure

• Both serve to focus attention to potential threat

• What about sadness, though?

Sadness

• May result in withdrawal from activities

• Could serve to conserve energy

• Seek out support; kin

• Pre-linguistically, emotional display of sadness may have served to elicit aid and support

Positive Core Emotions• Love

– Different forms: parents, children, mates– Influence on inclusive fitness

• Happiness– Joy --> play, develop mental & physical skills,

social development– Interest --> exploration, information seeking– Contentment --> “low arousal positive state”;

maintain successful situation