L6a Social and emotional brain 1

What is the social intelligence hypothesis, according to Dunbar and Shultz

the idea that aspects of social life have been the primary force shaping intelligent behaviour

What has the brain evolved to deal with – referred to as computational demand – according to the social brain hypothesis

complex information of the social word

Define feeding ecology

how a species obtains and uses food in its natural environment

What do differences in feeding ecology create

different cognitive demands

What is the ecological intelligence hypothesis, according to Rosati

the idea that cognitive abilities evolved partly to solve ecological problems e.g. finding and exploiting food resources

What can variables related to feeding ecology (e.g. diet quality, foraging complexity) predict in the body

neurobiological traits

Explain the difference in what the social intelligence hypothesis vs ecological intelligence hypothesis attributes brain evolution to

social complexity vs feeding complexity

What method did Isik et al use to investigate processing speed of social interaction perception when ppts watched images (of either non-social or social interaction)

EEG/MEG decoding

What were the two tasks in Isik et al following ppts watching two images

judging whether two actors were of the same/different gender and whether the image contained a social interaction

This was the speed of encoding for gender task (around 350ms), how did the time change for the social interaction task

time did not really differ, encoding for social interaction information occurred also 200-400ms after stimulus onset

This response time is considered fast or slow

relatively slow

What does the relatively slow speed of social interaction perception suggest about the underlying neural processes

suggests it is not a simple feedforward process and likely relies on information from multiple brain areas

What was the behavioural response time in the social interaction task (in ms)

600ms

What 4 pieces of social information does the face convey

others’ emotional states, attention/intentions (eye gaze), membership in social categories (e.g. gender), disposition (e.g. trustworthiness)

What 4 social cues does eye gaze provide

distinguishes between emotions, establishes dyadic communication, orient attention to critical objects, gives clues about intention

Recall to last weeks lecture, what two brain areas are involved in eye-gaze detection (clues: FFA and STS)

fusiform face area and superior temporal suclus

What task activates the FFA vs the STS, according to Hoffman and Haxby

face identity task vs eye gaze detection task

What does Haxby et al’s model attempt to explain (we looked at this in a previous lecture)

face processing and recognition

In the model, what does the STS process vs the FFA

changeable aspects of faces vs invariant aspects of faces (unique facial identity)

Study 1 by Saitovitch et al applied inhibitory TMS over the right STS, what was the impact on eye gaze and/or attention

led participants to look less to the eye region

What does this suggest about the role of STS

helps guide attention to the eyes, not only eye-gaze detector

It is assumed that STS detects eye-gaze, this could be simply any eye movements – Pelphrey et al aimed to test whether mutual and averted gaze evoke the same level of STS neural activity, what were the findings

mutual gaze evoked greater right-lateralised STS activity

What does this suggest and reinforce about STS assumptions

involved in the visual analysis of SOCIAL information conveyed by eye-gaze, not simply detecting eye movements

Pelphrey et al following up Study 2 with Study 3 which was interested in whether the context in which the eye movement occurs matters – tested congruent goal-directed vs incongruent non-goal-directed gaze shifts, which elicited greater activity and what does this show about the STS

incongruent, showing the STS is sensitive to violations of expected social behaviour

Study 4 by Materna et al – what were the results of STS activity in response to the two conditions

similar STS activity in both conditions

Complete the summaries of the previous studies

guide attention, visual analysis, eye-gaze, violations of expected, directional, pointing

Considering these summaries, is STS specialised for eye-gaze

no, not specific for the eyes or face

Pelphrey et al wanted to extend findings of congruent vs incongruent gaze shifts to goal-directed actions – ppts watched an animated character making movements either toward (congruent) or away from a dial (incongruent), which condition evoked greater STS activity

incongruent

What does this demonstrate about STS sensitivity

sensitive to violations of expected or goal-direct behaviour

This is different to gaze shift findings – what does this mean about STS function

ability to differentiate violation between predicted and actual behaviour

In previous lectures, we have seen that the STS is more active for biological motion compared to scrambled biological motion – Isik et al wanted to test whether STS preferentially engaged in perceiving social interactions vs independent actions (point-light figures), what were the results

STS responded more strongly to social interactions

What did Isik et al fand when using animated shapes (rather than human figures)

STS showed greater responses to socially interacting shapes compared to shapes moving in an inanimate manner

What do these findings tell us about what drives STS activity

perceived social interaction itself, not merely presence of human bodies/biological motion

From all these studies, what can we conclude about what STS role actually is

social meaning processor for dynamic cues

What 6 social information has the STS been evidenced to process (some we have identified, some not)

eye gaze direction, facial movements, biological motion, body actions, vocal cues, audio visual integration

What is then questioned about what input is required at this stage

purely relies on visual information or input from higher-level brain regions too

According to McMahon and Isik, how are seemingly high-level aspects of social interactions extracted

largely by visual processes

And what do they suggest to be one of the goals of the visual system

recognising social interactions

What are social primitives

basic visual features used to detect social interactions

Complete the steps of social interaction perception

body, face-selective, relative configuration, social interactions, STS, core components, higher-level cognitive

What is the third visual pathway proposed by Pitcher and Ungerleirder (3 areas)

pathway projecting from early visual cortex, via motion-selective areas, into the STS

What does the STS compute in this pathway

actions of moving faces and bodies

What is the third visual pathway specialised for

dynamic aspects of social perception

STS is seen as part of a network hub rather than a lone operator, fill the gaps

fusiform gyrus, figure, salience/relevance, medial prefrontal cortex, attention

What are two neuroscience methods used with infants

fMRI and fNIRS

What does fNRIS measure (similar to fMRI)

concentration changes of oxyHb and deoxyHb focally

Infants are drawn to faces with mor elements in the upper half or lower half

upper

What brain activity may reflect distinctively social processes early in infancy

cortical face-selective responses

What is the main mode of establishing communicative context between humans

mutual gaze

Through a looking time study in newborns, what is their visual acuity and what gaze did infants prefer

poor, direct gaze over averted gaze

Through an EEG study, what was their visual acuity and what processing of direct gaze did they find

high, enhanced neural processing

Using fNIRS, what changes in oxyHb concentration did Grossman et al find when infants watched dynamic scenarios in two gaze conditions

increases in oxyHb for mutual compared to averted gaze

What do these findings suggest about cortical areas in the infant brain and what it corresponds with

mutual gaze activates these area which correspond to adult STS regions

Fill the gaps of Simion et al findings on newborn preference for biological motion

discriminate between biological and random, biological, looked longer

Using fNIRS, what did Lisboa et al find about concentration levels in STS in response to coherent PLW vs scrambled PLW

increase concentration in STS for coherent PLW but no activations for scrambled motion

What does this suggest about the specialisation of STS in infants (specify age)

functionally speciflaised in biological motion configurations at 7-8 months of age

What is the overall developmental trajectory of STS social specialisation

face processing then indirect evidence for STS involvement in eye-gaze and biological motion, specialisation of STS for complex social signals emerges gradually during development