17. Evolution of emotions PDF

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Evolution of EmotionsInteresting things about emotions● The key emotions are friendly universal across human cultures ● There are parallels between emotional expressions in humans and animals ● Recent research indicates that emotions are central to decision making (emotions and cognition interact) ●...

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Evolution of Emotions Interesting things about emotions ●

The key emotions are friendly universal across human cultures

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There are parallels between emotional expressions in humans and animals

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Recent research indicates that emotions are central to decision making (emotions and cognition interact)

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Responses to emotional expressions are lateralized in the brain both in man and animals

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Emotional intelligence is likely to have important effects on social success ○

(considerable adaptive value)

Expression of emotion in man and animals – Darwin (1872) Darwin applied remarkably acute observation to study the facial and bodily expressions of cats, dogs, and infants

Human facial emotions ●

Darwin recognised that human facial expressions had a common evolutionary origin with non-human primates and were largely innate

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Paul Ekman identified the basic emotions in human facial expressions using photographs to study understanding of emotion in different communities

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Anger, fear, disgust, surprise, happiness, sadness

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Universality in human facial expressions first proposed by Darwin, and later demonstrate by Paul Ekman et al

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Photos from Ekman’s study (far left) in an isolated community in New Guinea: same associations made with different expressions except fear and surprise not well differentiated

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In addition to the 6 basic emotions, also social or moral emotions such as jealousy guilt, embarrassment Jaak Panksepp proposes a more neurobiologically inspired classification – 4 basic emotional systems, each associated with a particular set of neural structures and neurotransmitters ○

Fear

○ Seeking ○ Panic ○ Rage ●

Research properly documenting animal emotional states, in particular positive ones, is still lacking

Components of emotion ●

Triggered by events of some significance/relevance

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Encompasses a coordinated set of changes in brain and body

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Appear adaptive in that directed towards coping with challenge posed by triggering event

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Have onset, dynamic course and offset (contrast with moods)

Relevant dimensions 1. Level of arousal 2. Valence (positive or negative)

Definitions Many proposed, but few are comprehensive/can usefully be applied to both humans and animals

Basic definition -

an intense but short-lived affective response to an event which is associated with specific body changes (Boissy et al, 2007)

Evolutionary psychology – the emotions are specialised models of operation shaped by natural selection to adjust the physiological, psychological and behavioural parameters of the organism in ways that increase its capacity and tendency to respond adaptively to the threats and opportunities characteristic of specific kinds of situations (Nesse, 1990)

Key functioning of emotional signalling facilitates social cohesion and reduce uncertainty ● ●

Established emotional expressions may be employed ritualistically to signal eg) differences in dominance Emotion is crucial in decision making – adaptive functions of positive and negative emotions (negative emotions allow us to respond appropriately to aversive stimuli, positive emotions to make adaptive choices)

Very basic parallels in emotional expression in animals and humans:

( Panksepp 2005),( Leavens, 2009), (Davila ross, 2009) Laugher in great apes and humans Palatable/Unpalatable: origins of disgust When rats play they emit trains of high frequency (50Hz) Chirps - also induced when tickled (Panksepp 2005)

Evolutionary origins of the smile John Ohala -

acoustic origin of the smile

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threatening vocalisations in dominance displays typically involve bringing the corners of the mouth forward to lengthen the vocal tract and lower the vocal tract resonances (or formants) with the effect of making an animal sound larger

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Vocalisations used in displays of submission involve drawing the lips back – smile face – makes animal sound smaller

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Possible to identify emotional faces in chimps based on the action of particular groups of muscles (bared-teeth, relaxed open mouth/play face, scream, pant-hoot, stretch, pout, whimper, alert face) – Parr et al (2007)

Facial action coding system (FACS) in humans and chimps -

Originally developed for humans by Ekman and Friesen

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Action units in human and chimp face – Parr et al (2007)

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Convergence of action units involved in particular expressions

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Anatomical basis for every movement we make

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Still need to describe the emotional expressions that occur in different situations – expressions recognised by FACS still needs to be associated with particular emotional situations to gain insight into what animals are experiencing

Sheep discern emotions in other sheep and humans Tate et al (2006) -

When given free choice of 2 pictures, sheep show more than 80% preference for the calm sheep or the smiling human one

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Horses also discriminate key emotions – Wathan et al (2016) -

Horses has emotional memories (they have memory of a person’s emotions)

Understanding of emotion in animals may be quite sophisticated – Parr et al’s (2001) work on chimps -

Chimps have ability to match emotional meaning

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Waller et al (2016) demonstrated a crested macaque can predict social outcome from facial expression

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Aggressive vs positive facial expressions occurring, -

the chimp could pick out injury outcome for negative expression -

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Waller et al (2016)

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Creased macaque can predict social outcome from facial expressions

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Friendly experian => happy outcome vs sitting w/bite mark

Syringe => scream face

Lateralisation in processing of emotions Workman’s Theory (Workman et al, 2000) -

When presented with different chimeras of emotional expressions -

overall right hemisphere advantage, but shift back to left when processing pro- as opposed to anti-social expressions

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You think the person is more scared on the left cause u see it on the right hemisphere (left visual field)

They suggest a prosocial/approach/left hemisphere vs anti-social/withdraw/right hemisphere dichotomy

In animals -

Sheep and horses, like humans and chimps, use left-visual field cues more than right visual (predator is on the left) -

field for detecting negative emotion cues on faces

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Horses are better at matching owner’s voice to sight of owner when owner is in right visual field (left hemisphere) prosocial task

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Many species preferentially view predators with the left eye (right hemisphere) -

for antisocial/threatening stimulus

How do animals experience emotions? Difficult question to answer – requires innovative methods ● ●

Facial expressions, behavioural and physiological responses suggest strong parallels with humans As well as understanding adaptive significance of emotional expression, need to understand animal emotions to properly protect their welfare

Facial expressions ●

Worry expressions (brow raise) in dogs make them more likely to be adopted ○

mimicking the human worry expression made humans innately respond more.

Depression? ●

Workman and Reader, social competition hypothesis)

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When males lose their dominance position, serotonin fell dramatically and behaviour changed

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Relationship between mood and status in vervet monkeys that is apparently mediated by serotonin

Huddled, rocking back and forth, refusal to eat ect ■

Symptom of depression

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These behaviours reversed when monkeys were given Prozac (serotonin, reuptake inhibitor)

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Also, when alpha male removed from group and another given Prozac, this male became the alpha

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Behavior was reversed Prosac helped gain dominance

Cognitive Bias in animals – reviewed in Mendl et al (2009) Animals trained that one cue predicts a positive event and another a negative event ●

Subjects then presented with ambiguous (intermediate) cues

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Initial evidence that animals in a more negative affective (emotional) state are more likely to judge these ambiguous cues as if they predict the negative event ○

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(pessimistic response)

Parallel recent work on this in dolphins and rats ○

Tickled rats more likely to predict the ambiguous cue as positive ■

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(optimistic approach)

Dolphins engaged in more socialised synchronised swimming more likely to predict the ambiguous cue as positive compared to those who less socially synchronised swimming

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Positive emotions and animal welfare – well-being is not simply the absence of negative emotions, but also (and even predominantly) the presence of positive ones (Boissy et al, 2007)

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In humans, emotional intelligence affects social success eg) emotional intelligence of group leader affects performance of team (Koman and Wolff, 2008)

What about animals…? ●

There is an expanding new field of affective neuroscience

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But… relatively few studies have systematically investigated behavioural phenomena related to emotions in non-human animals or tried to directly relate emotional sensitivity to social behaviour

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Humans have the capacity for empathy, emotional and mental sensitivity to another’s state (from being affected by and sharing in this state to assessing reasons for it and adopting the other’s point of view)

To what extent are animals capable of empathy….? Rats and empathy – Bartal et al (2011) ●

Learn to open door to release a trapped rat from container

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When faced with two containers, one with trapped rat and one with chocolate chips, subjects opened both containers and shared the food (prosocial behaviour)

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Not just seeking company, will release the trapped rat into a separate cage

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Particularly interesting as this is not empathetic distress, rats appear to overcome any fear they pick up from alarm calls of trapped companion and act prosocially

Consolation -

where uninvolved bystander provides contact comfort to recent victim of aggression

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Horses, ravens, chimps

****need for more research in this area – more specific, not just suggestive research...