Lecture 22, 23, and 24

Lecture 22 cooperation 

• Altruism is common among genetic relatives 

  • Cost of altruistic behavior less than benefit to recipient times relatedness (measuring in bioloigval fitness) 

  • Costs mother fitness but offspring fitness is being enhanced 

• Cooperation among nonrelatives usually involves mutualism 

  • Costs and benefits at the same time 

Reciprocal altruism - involves temporal lag between giving an deceiving aid 

• Net cost at the time of assistance

• Might account for scarcity 

• Rare in animals - have to be able to tolerate debt and wait for benefit (delayed gratification) 

• Requirement for the evolution of reciprocal altruism 

  • B>C - benefit of recipient must be greater than cost for altruis t

  • Repeated interactions 0 have to be enough time for favor to be reciprocated 

  • If ercirpocity is evolved trait (adaptation) it should be present universally across human society and present throughout different times in history 

• Pervasive in human social life - adaptation helped us evolve certain problems throughout humans evolution

• Evolutions: 

  • We eat more meat than great apes 

  • hunte r gatherers depended on meat - reciprocal sharing of food is fundamental to survival 

    • Ancestral people who are not good at reciprocal sharing of food were selected against and would die

    • Have inclination for foodsharing because we are descendants of people that depended on it for survival 

• Psychological adaptations to support reciprocal atrium 

  • Trust 

  • Overcoming greed 

  • Discriminating agaisnt non reciprocators 

• Trust 

  • Amygdala seems to be involved in perceiving regsitering mistrust of others 

  • Can enhance trust by suppressing amygdala activity or making amygdala less active 

  • Ot might help trust by supressing amygdala (fear of betrayal)  activity 

• Overcoming greed 

  • Social reward outweighs singular reward 

  • Mutual cooperation reward greater than unilateral outcome 

  • People who activate thor ventral straitum after CC are more likely to cooperate again 

  • VSTR and OFC - reward from mutual cooperation - helps overcome greed 

  • OT increases VSTR activity - IT redneringn positive social interactions more rewarding because it is increasing activation in VT 

• Discriminating agaisnt non reciprocators 

  • Anterior insula (under sylvian fissure) - activated by a variety of various negative social interaction 

    • Responsible for the bad feeling we get when cooperation is not reciprocated - motivates us to not continue cooperating 

  • Aversive response to unreciprocated interactions 

• Other areas of brain 

  • Frontal pole 0- valuing long term benefits an relationships 

    • Envisioning long term consequences of beahvior and understanding that i will benefit from a relationship in the long run 

Prisoners dilemma 

• Tit for tat 

• Always start by cooperating 

• Unstabel equilibrium - temptation to defect for gain or fear that others will do that - mirrors relationships 

Lecture 23 language 

What is special about language 

• Voluntary - most NHp voclalizations are involuntary 

• Symbolic 

  • Msot animal signals are analog (identitiy, state of signaler) 

  • Not symbolic (abstract information) 

• Syntax - organization of communication above the level of the single symbol 

• Soem animals, such as parrots, dogs, andn NHP have limited symbolic abilities 

  • Dont exceed 1000 words 

• Only humans combine thousands of arbitrary symbols according to a defined set of rules to create a nearly infinite variety of meanings 

What is the function of language 

• Primates groom each other to build relationships 

  • Bigger groups, more relationships, more time spent grooming 

• Our ancestors lived in large groups, cant groom all those people, needed more efficient way of maintaining relationships and reinforcing social bonds 

  • Language evolved as a substitute for social grooming 

  • Way we could efficiently reinforce bonds with others 

  • Efficient for large groups 

• Mapping physical and social environments 

  • Gossip - to expand map of social environment 

• Coordingating acitons when cooperating 

• Teaching and learning from others 

  • Develops spontaneously 

  • Complex cooperation 

  • Cooperate with non relatives 

  • Lots of psychology and technology 

What are the neural substrates of human language 

• Classic model - wernickes and brocas areas 

  • Damage to wernicke - leads to deficits in speech comprehension 

    • Area 22 

  • Damage to broca - leads to deficit in speech production 

    • Area 44 and 45

  • Damage to arculate fasciculus - leads to deficits in word repetition, but intact speech comprehension and production abilities 

    • Cant repeat what they hear 

    • Pathway conveying info about the words that you hear forwarded to the part of the brain involved in speech repetition 

    • Involved in: 

      • Word repetition 

      • Naming 

      • Complex syntax 

      • Speech fluency 

      • Word and sentence comprehension

Transcortical sensory aphasia 

• Normal repetition, no semantic comprehension 

• Damage to area 21, 37, 39 - involved in lexicol semantic processing of the meaning of words 

Human brain specializations supporting language 

• Wernicke 

  • Humans - speech processing 

  • Macaque - call processing 

• Broca 

  • Humans - speech 

  • Macagque - no vocalization 

    • If lesion brocas area in monkeys they can still vocalize 

    • Vocalizations comings from limbic system - involuntary emotion expressions 

    • Has mirror neurons that aid communication (not vocal communication) 

• 3 neuroanatomical specilizations for human language 

  • Wider cortical columns in broca’s and wernicks’s area 

    • Suggests that there is more space for connections for input from other neurons 

    • Integrating more info 

  • Leftward asymmetries in broca’s and wernicke’s areas 

  • Expanded arcuate fasciculus 

    • Projections goes beyond wernickes area into lexicol semantic cortex (21) different from original model 

    • Pathway larger in left hemisphere than right 

    • Macaque has connection from brocas homolog to wernickes homolog but it is a very weak pathway 

    • Chimps have connection that goes down into lexicol semantic coretex but also very small 

    • Humans have massive project

• Visual cortical areas in monkeys and humans 

  • Human visual cortex in different position than monkey visual cortex because ther was an expansion of language cortex in human brain that pushed visual areas around 

Gene involved in human language 

• FOXP2 gene produces FOXP2 protein which is a transcription factor 

• Orofacial movement disorer manifest most strikingly during speech 

  • Trouble speaking - have less grey matter in broca’s area 

• Evidence of strong positive selection on FOXP2 gene during human evolution 

• Same version of gene found in neanderthals 

  • May have been capable of speech and language like us 

  • Gene believed to become fixed about 800,000 YA or earlier - before rmodern humans diverged from neadnerthals 

Lecture 24 empathy and theory of mind 

Three brain systems for understanding the minds of others 

1. Mirror neuron system 

2. Empathy system 

3. Theory of mind system 

Mirror neurons 

• Cells that discharge both when an individual makes a manual or orofacial gesture and when the individuals observes another individual making the same gesture 

• Found in area 44 broacs, 6 ventral premotor cortex in macaque, inferior parietal and inferior frontal cortex 

  • Mirror neurons in inferior parietal and frontal cortex are connected by fiber tracts (SLF 3) 

  • Mirror neuron circuit - parietal mirror neurons talk to inferior frontal mirror neuron via SLF 3 pathway 

• STS codes the actions of others,, SLF 3 transmits info,, PF  anad 44/6 maps actions 

• Maps seen motion onto own motor cortex

• Runs simulation of movement and then does movement 

• Form a natural link between the sender and the receiver of a gesture that allows the receiver to simulate the brain state of sender 

  • Simulation theory - we understand others by imagining our own behaviors, feelings, or thoughts in a similar situation

  • Allow receiver to grap the intentions of the sender  

Human mirror neurons 

• Inferior paritel and inferior frontal 

• Mirror neurons allow us to map the observed actions of others onto our own motor repertoire so that we can better understand the action adn the intent behind it 

• The mapping is stronger when we have experience with the observed action 

Empathy system - emotional empathy 

• Empathy - an affective state caused by sharing of the emotions or sensory states of another person 

• Anterior insula activated when empathy is evoked 

  • Higher empathy score, more activation in insula 

• More gray matter density in anterior insula , more empathy 

• Might be able to train insula to become more empathetic through mediation 

Theory of mind system - cognitive empathy 

• Theory of mind - the ability to make inferences about the mental stsates of others, including what they now, believe, and intend ot do 

  • TOM stimuli in studies : 

    • Stories with fake characters 

    • Cimic strips in fake characters 

    • Interacting geometrical shapes 

    • Real social interactions that people are personally embedded in 

• Brain areas: 

  • Dorsomedial prefrontal cortex 

  • Posterior STS / temporal parietal junction 

  • Posterior cingulate / precuneus 

  • Mostly cortex 9very cognitive)