12. The Psychobiology of "mind reading" Flashcards
What is the social brain/Machiavellian Intelligence hypothesis?
Dunbar (1998) – human intelligence evolved primarily as a means of surviving in complex social groups
What behaviours are demonstrated according to the social brain/Machiavellian?
Reciprocal altruism, deception, coalition formation
What do group dynamics relate to according to the social brain/Machiavellian Intelligence hypothesis?
They relate to the theory of mind – the ability to understand the thoughts/emotions/intentions of others
What did Dunbar suggest about social groups?
Dunbar suggests that as social group size increases, the complexity of managing social/political relationships increase
- Chimps live in groups of ~50
- Humans (traditionally) live in groups of ~150 (Dunbar’s number)
- The social brain hypothesis: when hominids started living in large groups, selection favoured greater intelligence
What is the social intelligence hypothesis?
In mammals there appears to be a correlation between brain size and social group size. In anthropoid primates, mean social group size correlates with relative neocortex volume
What is an alternative suggestion to the socialness of the brain according to Miller (2000)?
SUMMARY: intelligence is a way of showing-off, and making people think you are sexy
Miller (2000) argues that human intelligence is unnecessarily sophisticated for the needs of hunter-gatherers to survive.
He argues that the manifestations of intelligence such as language, music and art are of no utilitarian vale to the survival or ancient hominids
Rather intelligence may have been a fitness indicator
What do our faces convey?
They convey messages about our inner states
What do monkeys say about how we look?
Chimpamzees, gorillas and bonobos – were more likely to follow the experimenter’s gaze when he moved only his head. In contrast, the 40 human infants looked up more often when the experimenter moved only his eyes: Tomasello, 2007
What are the effects of being alone?
“The magnitude of risk associated with social isolation is comparable with that of cigarette smoking”: House, 2001
What does living alone increase?
Living alone increases the risk of depression and suicide.
Lonely individuals report higher levels of perceived stress
Loneliness raises levels of circulating stress hormones and levels of blood pressure
What is the relation between human behaviour and being “social” creatures?
There are very man aspects of human behaviour that seem to indicate that we are, at a fundamental level “social” creatures
The scientific examination of the mind, brain and cognition should take this into account
What are the brain systems underlying social perception?
Understanding actions
Understanding faces
Understanding emotions
Understanding intentions
What is involve in the Brother’s Bold program?
Gaze detection Metalizing Social judgement Affect recognition Facial perception
How do we understand the actions of others?
- We gain most of our information about the world through visual perception
- Motion is important for understanding action
Biological motion
Johansson (1973) – “point light” animation sequence
Motion helps define form?
When can biological motion be perceived and what can be perceived?
Biological motion can be perceived even when embedded in masks of dots (Perrett et al., 1990)
Gender of the walker can be perceived (Cutting, 1977)
Facial expressions of emotion can be recognised from point-light display (Bassili, 1978)
Social (threatening, greeting etc.) and instrumental actions (lifting, ball bouncing) can also be recognised (Dittrich, 1993)
Identifying basic emotion from dance (Dittrich, 1996) 83% correct in normal viewing – 63% correct to point-light displays
When is the posterior superior temporal sulcus activated?
Posterior STS is activated during the perception of point-light displays (Grossman et al., 2000)
Also activated to more complex social stimuli involving implied/actual motion (Puce et al., 2003)
What does Transcranial Magnetic stimulation distrupt?
TMS to this area disrupts the perception of point-ight displays (Grossman et al., 2005)
How were mirror neurons discovered?
Accidentally in the early 1990s by researchers working on single cell recordings in the macaque motor cortex
When do mirror neurons fire?
Mirror neurons fire whilst a monkey performs an action, and whilst it observes the experimenter performing the same action
What did Di Pellegrino et al., 1992 discover about Area F5 and the central premotor cortex?
Out of 184 F5 neurons sampled, almost all were activated during movement
12 of these neurons (6%) responded to the same action when executed as when observed (strictly congruent mirror neuron)
17 more (9%) responded to logically related or visually similar actions, fire as long as goals and intentions match (broadly congruent)
How did Umilta (2001) indicate that mirror systems seem to encode intentions?
In B and D visual input is identical. Differences in spiking must be due to knowing that the object is or is not there.
Therefore concluded that such mirror neurons discriminate between reach and reach to graspt
And therefore encode intentions
How were mirror neurons observed in humans?
Participants observed or imitated the lifting of the index or the middle finger (top).
In visual control conditions they observed a cross appearing on the index or middle finger of a static hand (middle), or appearing on the left or right side of a grey rectangle (bottom).
In motor control conditions, participants lifted the index or middle finger in response to the appearance of the cross.
The two areas showing the predicted pattern of higher activity for the control motor task compared with action observation, and highest activity during imitation, were located in the inferior frontal cortex (Brodmann’s area 44; BA44) and in the rostral part of the posterior parietal cortex (PPC)33.
What did the Superior Temporal sulcus provide the mirror neuron system?
The superior temporal sulcus (STS) provide the MNS with high level of visual description of the observed actions of meaningful motion by an animate agent
Inferior Parietal Lobule
Concerned with motor modelling of observed behaviour
Inferior Frontal Gyrus
Concerned with intentionality
Are faces a “special” class of object?
Several lines of evidence converge to suggest that faces are processed by neural mechanisms that differ from those used to process objects
What is the evidence suggesting that faces are processed by neural mechanisms?
- Behavioural evidence
- Developmental evidence
- Lesion studies
- Monkey neurophysiology
- High spatially resolution imaging techniques
- High temporal resolution imaging techniques
What is the facial inversion effect?
A variety of types of judgements about faces are more difficult when faces are presented upside down.
What do the facial inversion effects imply?
They imply orientation sensitive processes that are specific to faces as opposed to other classes of objects.
e.g. Thatcherised faces (Thompson 1980)
