human social interaction perspectives from neuroscience
DESCRIPTION
1. Human Social Interaction perspectives from neuroscience. Dr. Roger Newport Room B47 Student Drop-in: Tuesdays 12-2 www.psychology.nottingham.ac.uk/staff/rwn [email protected]. Understanding Action: social visual cues and biological motion. This lecture: - PowerPoint PPT PresentationTRANSCRIPT
Human Social Interactionperspectives from neuroscience
Dr. Roger NewportRoom B47
Student Drop-in: Tuesdays 12-2
www.psychology.nottingham.ac.uk/staff/rwn
Understanding Action: social visual cues and biological motion
1
This lecture:
Your marks and stuff
Part 1 -
Social visual cues - the importance of eye gaze
Part 2 -
Social visual cues - detecting human motion
I Went to church last Sunday
She passed me on by
I knew her mind was changing
By the roving of her eye
The face provides information about:identityperceived personalityemotional state
The eyes provide information about:direction of attentionemotionintentionsocial statussocial rulesromantic attractioncorriedoo
Understanding actions: The head and eyes
The face is the most important object that we see every day.
Within the face the eyes are the most important feature.
2
Low-gazing females are rated as less-attractive by males
Objects that are gazed at by attractive people are rated as more desirable
IDIntentionality
Detector
TOMMTheory of Mind Mechanism
SAMShared Attention
Mechanism
EDDEye direction
Detector
5aThe eyes - models of eye gaze processing
Baron-Cohen
ID - primitive mechanism that interprets motion in terms of desires & goalsEDD- detects eye-like stimuli & works out direction of gaze. Attributes ‘seeing’ to the ownerSAM - links above 2 & identifies when you and other are looking at same thingTOMM - infers mental states
5bThe eyes - models of eye gaze processing
Emery
A: L and T looking at each other vs notB: L detects that T is not looking at them and follows B’s gazeC: L&T looking at same thingD: Combination of A and C - both know that they are both looking at the same thingE: Inferring intentions using a combination of D and higher order mechanisms
Farroni et al., 2006. Eye gaze processing: an innate skill?
Babies (1-5 days old) prefer to look at upright straight head direct gaze vs. others
4
A primitive configuration mechanism?
By 4 months infants a) Prefer direct to averted gaze
b) Can follow gaze
c) Will orient more rapidly to a location cued by an adult
The eye as a special stimulus. Response of cells in striate cortex.
An evolutionary advantage for efficient gaze processing 6
Various mammals have developed specialised systems for detecting eye-like stimuli
Rapid detection and reaction to predators
Psychophysical evidence for a specialised eye detection system
Fast
Slower
7
Automatic and obligatory processing of gaze
Human psychophysical evidence for a specialised eye detection system
8
Systems active for arrows different to those for gaze.
Eye gaze processing is special. Hietanen et al., 2006 1
Perrett, D.I. et al. (1985)
Monkey cell gaze preference
Where in the brain? Evidence for STS involvement: animal studies
Neurophysiological responses from cells in the superior temporal sulcus of the macaque to indirect and direct eye contact of conspecifics (adapted from Perrett & Mistlin, 1990).
10
Evidence for STS involvement: Monkey lesion studies 11
Eye gaze processing is impaired following STS lesions
Unable to make gaze-direction judgements, but unimpaired on other face processing tasks.
Various Perrett et al., studies
STS activation in humans12
From Allison, 2000
Wicker PET averted vs. mutual gaze videos
H&H fMRI static images
Puce fMRI alternating static gaze
STS, but not MT
Subtracting neutral from cued removes STS activation
Hietanen et al., 2006 Why no STS activation? 14
Evidence from Autism
Autistic children have difficulty using gaze information to interpret the intentions of others. Any evidence related to STS activity?…
Which sweet does Charlie prefer?
Which one is looking at you?
15
Pelphrey et al., 2005
N A
Eye gaze related (A&B) and incongruence related (C&D) STS activity
16Evidence from Autism
Human neuropsychological evidence: Patient MJ - a rare STG lesion
Look it up yourself et al., 2006
17
Perrett’s DAD
IDIntentionality
Detector
TOMMTheory of Mind Mechanism
SAMShared Attention
Mechanism
EDDEye direction
Detector
B-C’s EDD23
24
Does this fitPerrett’s DAD?
Human psycho-phyiscs
Congruent v incongruent head and eyes
Task, to indicate eye direction regardless of head and vice versa
C CI I
Eyes Summary
There are various facial visual cues that can inform us about the direction of attention of others
Of these they direction of gaze seems to be the most readily detectable
Although gaze may be the most important, gaze alone is not sufficient to tell us about another’s direction of attention
Cues from eye, body and head direction are possibly processed in parallel
All this seems to be processed in the STS
This information should be taken into account when designing models of social behaviour
25
Dr. Roger NewportRoom 331
Office Hours: Tuesdays 10-12
www.psychology.nottingham.ac.uk/staff/rwn
Human Social Interactionperspectives from neuroscience
Understanding Action: biological motion
1
What is special about Biological motion?
Actions often used for social communication
Actions involve movement
Detection of biological movement (i.e. of animals) important for survival
Evolutionary advantage often = specialised neural network
Innate skill? ability from 3 months.
Goes beyond facial expressions and social attention cues:
Biological motion
Non-biological motion
2
From bio motion we can perceive:
Identity (face/body movement)
Gender
Attractiveness
Affect
Intentions
What is special about Biological motion
Goes beyond facial expressions and social attention cues:
Social intentions
3
BMLwalker
Observing point-light displays
Observing real vs robot
http://www.biomotionlab.ca/Demos/BMLwalker.html
4Ways of studying biological motion
http://www.psy.vanderbilt.edu/faculty/blake/BM/BioMot.html
Types of point-light stimuli used in studies
5
Scrambled, inverted and normalMotion
Ways of studying biological motion
Perrett studied 50 ‘hand action’ STS cells as monkeys viewed various human hand movements(1) Most cells responded best to particular movement type(e.g. grasping vs. retrieving action.(2) Responsiveness for that action generalized across objects(3) Responsiveness generalized across various ways of makingthe same action (e.g. fast versus slow, near versus far (4) Responsiveness was greater when the action was goal-directed;
Cells therefore encode particular goal-directed hand actions.
Cells in superior temporal polysensory (STP) cortex in monkeys receive inputs from dorsal (action) and ventral (perception) streams (integrating form and motion).
Such inputs would allow the detection of form from motion. Some cells in STP respond selectively to biological motion.
Evidence from monkey studies (mainly Perrett et al.) 7
Random dots drifting left or rightRandom dot cube rotating left or rightRandom dot cube rotating left or right with masking elementsUpright point-light walker facing left or rightInverted point-light walker facing left or right Upright point-light walker facing left or right with masking elementsInverted point-light walker facing left or right with masking elements
Human imaging studiesGrezes et al. 2001STS activationRed = walkerGreen = cubeBoth = yellowNote bio always more anterior than nonbioLeft IPS non-rigid bio motion
9
NB masked inverted BM not detected in behavioural task
Activation in this subject is bilateral, but most subjects showed a right hemisphere bias
Grossman and Blake, 2001
Posterior STSBio>InvertedInverted>scrambledBio>imagined
Human imaging studies10
Human imaging studies - difference between motion sensitive and Bio motion sensitive areas
Beauchamp et al. 2002
11
(A) Grand averaged ERPs across 12 subjects elicited by biological (blue) and scrambled (red) motion.
(B) Scalp distribution of ERP difference amplitudes (ERP amplitude in bio motion condition minus scrambled motion).
Clear differences (increased activation) observed after 200 ms in right occipitotemporal region (STS probably) 200ms after stimulus onset
13
Grossman et al., 2005 10 min 1Hz rTMS
Pre-baseline
STSPost baseline
MT
Upright Inverted
Posterior STS rTMS disrupts bio motion
14
Patient ALDamage to right OT Junction (plus massive LH damage)Couldn’t see form from motioncouldn’t see Johannson figuresCouldn’t recognise familiar people if they moved
but could describe motion itself (direction of).
Dissociation with LM (Zihl’s famous akinetopic patient) who could not see first order motion
AL and LM’s lesions barely overlap. LM more posterior.
Evidence from lesion studies15
Evidence from Schizophrenia 16
Deficits in motion perception have been suggested as an important feature of schizophrenia (results based on e.g. velocity discrimination)
ST cortex volume is reduced in schizophrenia patients Do schizophrenics have deficits in biological motion perception?
Kim et al., 2003:task to judge whether point-light animations looked human or not
Half the stimuli were from a real person in motion (e.g. dancing, jumping, walking etc). Other half were scrambled versions
control task: perceptual grouping task,
Schizophrenia patients showed deficits in detecting biological motion but not in the control task
Detecting head and eye direction seem to interact
Timing of neural response to head and eye gaze inconclusive so far
Are the neural correlates of gaze processing affected by head orientation and task demands?
Explicit versus implicit gaze processing assessed by ERPs
Viewed images of direct or 3/4 turned head with averted or direct gaze. 1) made gaze judgments (explicit gaze task), 2) made head orientation judgments (implicit gaze task).Measured ERPs + behavioural RT task
Current Research October 2007
Rationale
Methods
Results
Behavioural task: incongruent head and eyes slowed RTs and lowered accuracy. Best performance in straight head AND eyes conditionSuggests gaze processed automatically regardless of task demands
ERP analysis:Greater response at 400-600ms for straight gaze regardless of task
The STS processes biological motion
Does it process body part-specific motion, or movement-specific motion?
If activations overlap then movement-specific, if not then body part-specific
Common and distinct brain activation to viewing dynamic sequences of face and hand movements
fMRI
Current Research September 2007
Rationale
Methods FaceHand andGratingAll radial motion (so same type of motion)
Green = all motion (all motion - fixation condition)Blue = hand vs radialRed = face vs radial (showing different area to hand)
Purple = hand v radial and face v radial overlap in pSTS (i.e. motion-specific, not body-specific area)
Results
Infants < 18 months do not have a pictorial representation of the human body
Infants ~ 6 months are compelled by biological motion
Do infants treat human bio motion as a solid human form?
Infants perceive human point-light displays as solid forms
Point light stimuli that pass through or behind a solid object
Current Research July 2007
Rationale
Methods Results
Infants look for longer (are more interested in) violations
Summary
Detecting eye, head and body movements are essential for normal everyday human social interaction
Eye gaze and biological motion are special
They have dedicated brain regions and may be innate
The STS region of the brain is crucial to these functions
Parts of the STS may be action-specific
Damage to this area may impair normal human social interaction