Darwinian / Evolutionary approach

Lecture # 2: September 22, 2004

Definition of emotion• Definition of Emotion: (Frijda, 1986; Oatley, 1994) • Emotions are caused by a person either consciously or

unconsciously evaluating an event as relevant to a concern or goal that is important in the sense of survival or adaptation.

• The core of an emotion is a readiness to act and the prompting of plans, to give priority to one or a few kinds of plans, to which it gives priority and a sense of urgency and interrupts ongoing mental processes or actions.

• Experienced as a distinct type of mental or phenomenal state (feelings), sometimes accompanied by physiological / bodily changes, expressions, characteristic thought patterns, and actions

PSY 394F Lecture # 2

Darwinian / Evolutionary approach

Sept. 19, 2001

Charles Darwin• Some biographical facts• Voyage on the Beagle as unpaid naturalist to

Galapagos Islands• Struck by the unique forms of life observed there,

Darwin became convinced that species are taken in different directions when isolated from one another, but could not think of any mechanism.

• Essay on Population by Rev. Thomas Malthus gave him the mechanism a couple of years later: Malthus had said that population multiplies faster than food or other resources.

• Species must compete to survive: so that nature acts as a selective force, killing off the weak, and forming new species from the survivors who are fitted to their environments.

• In terms of emotional expressions, Darwinbelieved that they are part of a great continuum in nature which reflects the operation of natural selection on such behaviours.

• Led to the publication of his last major work “The Expression of Emotions in Man and Animals”.

• As sources of data, Darwin drew on evidence– From expressions in infants (his son William)

– From observations and examinations of humans

– From observations of expressions in animals

– From observations of ‘the insane’

– From observations of expressions in people across cultures

• Darwin described in painstaking detail the facial expressions and bodily movements that accompany the major emotions in humans and other animals

Sneering / Defiance (the model in this photo is the photographer’s wife!)

Source: The Expression of the Emotions in Man and Animals (1872;1998) with commentary by Paul Ekman

Dubious Evidence

Source: The Expression of the Emotions in Man and Animals (1872;1998) with commentary by Paul Ekman

Darwin’s Principles Governing the Evolution of Emotional Expression

1) Serviceable Associated Habits

2) Principle of Antithesis

3) Direct Action of the Nervous System

Principle of Antithesis

Source: The Expression of the Emotions in Man and Animals (1872;1998)

with commentary by Paul Ekman

Ekman’s Cross-cultural Studies

• Ekman and colleagues (1969) studied the Fore of New Guinea: a neolithic culture isolated from Western influence until 12 years prior to research.

• From 3000 photos, selected 30 which displayed ‘pure’ expressions of emotion: happiness, sadness, anger, fear, surprise, disgust.

Ekman et al. (1969)

• Study 1: Fore were shown photos one at a time, and had to choose from a set of translated emotion words.

• Recognition was 99% for happiness in subjects who spoke pidgin and 82% for those who spoke only the Fore language. Recognition was not as good for negative emotions (56% average). Tendency to confuse sad and angry faces.

Ekman’s 1971 Study

• Choice from a fixed set of labels had not worked very well, so Ekman had the Fore informants construct small vignettes for each target emotion.

• After the story was told, the subject had to indicate by pointing at one of three pictures of faces, which one corresponded to the emotion that would be consistent with the story

Ekman’s 1971 Study

Source: The Expression of the Emotions in Man and Animals (1872;1998) with commentary by Paul Ekman

Results: Happy story– 90 % chose the happy face

Sad, Angry, Disgust stories– 69-89% chose the correct face. Fear and Surprise were not discriminated at levels exceeding chance.

• Ekman and Friesen subsequently gave emotion stories to the Fore people, asked them to make the appropriate facial expressions, and videotaped these expressions.

• Tested American students upon returning to San Francisco. 46-73% of students made correct judgments for four of the six faces. Fear and surprise were confused, as they were for the Fore.

Source: The Expression of the Emotions in Man and Animals (1872;1998) with commentary by Paul Ekman

Problems with Ekman’s research

• Linguistic: Did not speak the Fore language and so could not monitor the informants

• Sorenson (1976) acknowledged that inadvertent cues could have been given to subjects by informants because the notion of a controlled experimental situation was unfamiliar to the Fore, and inconsistent with their view of language and communication as a collaborative activity

Problems with Ekman’s research

• Choosing from a fixed set of emotion labels or pictures may overestimate accuracy

• Sorenson (1976) conducted a similar study that allowed for open ended responses

• Anger, fear and happiness showed high degree of accuracy, however the sad face was often called angry, and inconsistent results for disgust and surprise as well.

Problem with Ekman’s approach

• Not just studying whether spontaneous facial expressions occur in other cultures under similar eliciting conditions, but also:

• Judgment task involves perception and interpretation of emotional expression… that emotional expressions are recognized and meaningful

• Thus, an implicit assumption of this approach is that facial expressions serve communicative functions: do they?

Evolution of Communicative Function of Emotions

• Andrew (1965)• Emotions were originally reflexes that had

functions that were not communicative (e.g. like Darwin’s notion of SAH).

• New evolutionary steps as these tendencies arose for these actions to be recognized

• Functional– positively selected for (e.g. it is advantageous to know when someone, or something is going to attack).

• These became pre-linguistic means for signaling intentions.

• Outline scripts: set up particular kinds of interactions (approaching with a smiling face sets up a very different kind of interaction than approaching with an angry face).

• Thus, emotional expressions did not originate for communicative purposes, but evolved that way.

Instincts / Action Patterns• If we accept the position that facial expressions and the

subjective experiences that are presumed to underlie them are part of our evolutionary heritage, evolved, are adaptive, then what are their functions?

• Instinct: a genetically based extended pattern of action. Hess: Stimulation of hypothalamus of cat leads to attack behaviour.

• Complex behavioural patterns, not simple reflexes. Usually elicited by a feature or event in the environment and become more skilled with learning.

• A kind of genetically determined start-up program.

• Lorenz (1937): Instincts are characteristics of particular species, like anatomical features

• Maternal caregiving in greylag geese• First Component: Fixed action pattern

– Not entirely fixed, develop within lifetime and responsive to environmental features

– Replaced by the notion of “species typical patterns” which don’t evoke the notion of fixed sequences of actions, but rather are goal-directed patterns of behaviour

– The knowledge of how to accomplish the goals of species-typical patterns is not conscious but compiled into the animal’s nervous system through evolution as a set of ‘outline procedures’.

• Second Component: Sign Stimulus– The perceptual pattern that triggers the script.

Even crude features are effective.

• Third Component: Motivational State– E.g. In greylag geese, egg-retrieving only

occurs during incubation period.

Evidence for Emotions as universal / inherited / evolved

• Eibl-Eibesfeldt (1973) Children born deaf and blind make expressions such as: Laughing, smiling, crying, frowning, surprise, startle, pouting, clench fists in anger.

• Field et al. (1982). Babies not only make facial expressions, but can also discriminate among happiness, sadness, and surprise, and also imitate adults’ expressions.

Sabine: Showing facial expression of happiness, even though she was born deaf and blind

Source: Plutchik (1994) The psychology and biology of emotions.

Ekman’s Neurocultural theory

• Innate neural patterning of expressions

• Display rules: Culturally relative rules that regulate and determine whether and when each expression can be made.