Chapter 6

Social Development

Early Child Development

• Gradual progression to full theory of mind

• Genetic component driving the stages

• Environmental interaction

• Social cognition a necessity for more advanced human social development

Development

• What is the purpose of childhood?

• Humans have extended period before becoming reproductively capable– Doesn’t this cut into reproductive success?

• Ultimate explanation: childhood prepares for adult reproductive phase

Life History Theory

• LHTs see development processes as means of maximizing inclusive fitness

• Development not a passive process

• “Decisions” during development may be due to environmental factors interacting with genes

Principle of Allocation

• Somatic effort– Foraging, survival, learning, growth, etc.

• Reproductive effort– Mating, producing, and rearing offspring

• Trade-offs

• No single/unique method for optimization

Reproductive Effort

• Broadly speaking, two techniques– Quantity: many offspring, limited investment– Quality: few offspring, high investment

• Environmental constraints determine which strategy will be most successful

• Male/female differences

Reproductive Strategies: Terms

• Between species– r: produce as many offspring as possible– K: produce few offspring

• Between individuals– C: maximize current fitness– F: maximize future fitness– From parent’s or offspring’s perspective

Offspring Predicting the Future

• Attachment strategies due (in part) to interaction with parents

• Childhood condition serves as model for future when reproductive phase reached

• How stable/unstable will future be?• Attempt to maximize reproductive success

– Stable --> future fitness– Unstable --> current fitness

Correlations with Father Absent

• Precocious sexual development• Boys more aggressive, rebellious, sexually

exploitative as adults• Girls have negative sexual attitudes, fewer long-

term monogamous relationships as adults• Single mother family lower economics, lower

resources• Offspring adopt “current” reproductive strategy to

maximize inclusive fitness

Early Environment

• Maternal attachment theory– John Bowlby, Mary Ainsworth, Jay Belsky

• Insecure avoidant (~25%)– Shorter-term relationships

• Secure attachment (~65%)– Long-lasting, stable relationships

• Insecure resistant (~10%)– Over commitment to few relationships

Selection

• Insecure avoidant and insecure resistant seem maladaptive (should have been selected against)

• But, possibly optimal given different life-history environments

• Different attachment styles (acquired during development) let offspring “plan” for future

Belsky (1997)• Secure attachment

– Stable developmental environment– Parenting over reproduction (maximize quality over

quantity; future)

• Insecure-avoidant– Availability of resources low, parental attention

irregular/inconsistent/unwilling– Reproduction over parenting (maximize quantity over

quality; current)

• Insecure-resistant– Speculative; parents unable to contribute?– Reduce direct fitness, but gain some inclusive

Genes and Environment

• How much of development is genetically regulated?

• Environment does interact with genome, but to what extent and when?

• What aspects of the environment are significant for development?

Behavioural Genetics

• Identifying gene-environment interactions for specific behaviours

• The old nature-nurture issue

• Monozygotic and dizygotic twins, biological siblings, adopted siblings

• Same or different environment

• Look for variation in behaviour

Identical Twin Studies

• Genes account for some 40-50% of variability, environment 50-60%

• Shared environment– Factors common to all siblings– 0-10% of environment variability

• Non-shared (unique) environment– Factors specific to an individual– 40-50% of environment variability

Non-shared Environment

• E.g., sickness, specific teacher, uterine environment

• Experiences that one child has but his/her siblings do not

• Peer groups could be very significant

• Group Socialization Theory– Judith Harris (1995, 1998)

Group Socialization Theory

• Peers better role model for child than parents

• Harris argues parents (adults) provide very little actual guidance/control over socialization development

Harris: Why Imitate the Young?

• Youth are innovators; cultural innovation can increase fitness

• Imitating peers over parents increases behavioural variability in culture

• Parents may not always be around; peer groups always are

• Parents and children often have competing interests

• Individual, not culture that is level of selection

• Again, culture not the level of selection

• In EEA orphans have bigger problems than no role-model parent; likely to starve, etc. Any adopting adult could serve as teaching model

• Children also compete with their peers, not just their parents

Evaluation: Parents have Little Lasting Socialization Influence

• Many early childhood developmental studies disagree

• E.g., best predictor of child’s verbal ability is amount parents talk and/or read to child

• However, there are the behavioural genetics findings of identical twins reared together or apart

Evaluation: Importance of Peers

• At this point, Harris’ assertions are somewhat “just-so stories”

• E.g., Different attitudes in two siblings could be due to the children joining different peer groups, but what motivates joining different groups?

• Could be chance factors (see Pinker 2002) or interaction between parental behaviour and child personality (see Vandell 2000)

Belsky (2005)• Children differentially susceptible to parental

influence; an adaptation in and of itself– In stable environment beneficial for children to imitate

parents– In unstable environment, what worked in your parents’

generation may not apply to yours

• World goes through periods of stability and instability– Might be adaptive for parents to have offspring that will be

differentially susceptible, depending on environmental conditions

– Belsky proposes ice ages as mechanisms– But, what about different ethnic groups, or pre- Out of

Africa period?

Social Development: Morality

• The individual is the evolutionary unit of selection

• Doesn’t moral behaviour act to benefit the group, though?

• Moral behaviour may have direct benefit to individuals in the group, though

• Also, remember that in the EEA the group would have contained more genetic relatives

Benefit the Group, Benefit Self

• A stable group is a safe, secure group

• The individual in such a group, benefits from a predictable, stable environment

• This can lead to improved fitness

Example: Reciprocity and Cheating

• Reciprocal arrangements benefit both parties (i.e., everybody wins)

• By cheating, one benefits, one loses• If cheating becomes common, no benefit to

initiating a reciprocal altruistic interaction• Now, no one benefits• Difficult to structure social interactions in an

entirely selfish environment• If group breaks up, e.g., may be harder to find food,

provide shelter, gain mates, childrear, etc.

Textbook

• Origins of morality

• Variability of morality

• Universal morality

• Well covered in text, so I’m going to leave it for you to go through this content on your own

Mirror Neurons

• Scattered throughout premotor cortex, centres for language, empathy, pain

• Fire when certain actions are preformed by or observed in someone else

• “Mental imitation” of witnessed (or heard) actions

Discovery

• Giacomo Rizzolatti, Vitorio Gallese, & Leonardo Fogassi

• “Raisin incident”

• Macaque monkey with electrodes in premotor cortex

• Published in 1996

Locations in Humans

• More mirror neurons in more places than in monkeys

• Premotor cortex (movement)• Inferior parietal areas (perception)• Posterior parietal lobe, superior temporal

sulcus, & insula (comprehend another’s feelings, understand intention, and use language)

Role

• Learning through imitation

• Understanding meaning or intention of action

Gallese, et al. (2005)

• Subjects listened to sentences describing actions

• Same mirror neurons fired as would have if subjects had done the action or seen the action performed

• Mirror neurons responded to abstract representation (i.e., language)

Mirror Neuron Sets

• Iacoboni et al. (2005)• Basic set: corresponding to an action’s most

essential form (e.g., reaching)• Supplemental sets: selectively fire

according to action’s perceived purpose (e.g., picking up glass to drink or to clear away mess on table)

• Role in understanding intentionality

Empathy

• Wicker (2005)

• Feeling disgust and seeing a look of disgust activated same set of mirror neurons in insula

• Allows direct “understanding” of someone else’s emotional state

• Social cohesion

Mirror Neuron Failure

• Autism

• Mirror neuron trouble may link to problems with language, learning, and empathy

Studies with Autistics• Autistic children showed less mirror neuron

activity than normal children when watching finger movement (basic set failure)

• Both autistic and nonautistic teens imitated and identify distinctive facial expressions, but the autistics didn’t show mirror neuron activity (supplemental set failure); autistics know the expression cognitively, but felt no empathy