Personality, Biology and Learning Flashcards
Heritability formula
Vg/Vp = h squared
What does Molecular genetics do?
Attempts to link personality traits to single genes
E.g. DRD4 gene alleles longer in those with higher sensation-seeking (Benjamin et al 1996)
Problem with candidate gene studies?
BUT candidate gene studies have not generally replicated (Plomin et al 2016
more often what are traits the result of?
but….
Of many genes acting together
- the largest effect sizes detected are extremely small for both disorders and traits (e.g., Chabris et al., 2015; Plomin & Deary, 2015)
So What Do We Know? (Plomin et al, 2016)
•All psychological traits show significant and substantial genetic influence.
•No traits are 100% heritable.
•Heritability is caused by many genes of small effect.
•Phenotypic correlations between psychological traits show significant and substantial genetic mediation.
•The heritability of intelligence increases throughout development.
•Age-to-age stability is mainly due to genetics.
•Most measures of the ‘environment’ show significant genetic influence
.•Most associations between environmental measures and psychological traits are significantly mediated genetically.
•Most environmental effects are not shared by children growing up in the same family.
•Abnormal is normal
Effect size shared environment (vs non shared)
Shared environment effect often negligible•Always smaller than a non-shared – individual, unique experiences
Rhee and Waldman 2002
Antisocial behavior in adolescence
•Shared effect = 15%
•Nonshared effect = 40
Matteson et al (2013)
Shared effects from 0.00 – 0.26
•Nonshared effects from 0.42 – 0.62
Within family factors
Within Family
•Positive and negative feedback loops
•Parent effects
Driving similarity between twins
Expected differences due to birth order
•Child effects
Gender
Health status
Outside family factors
Context specific socialisation
•Outside the home socialisation
•Transmission of culture
•Group processes that widen differences between groups
•Group process that widen differences between individual
Skinner 1948
Operant conditioning •Not personality – learning history •S-R responses formed by •Operant schedules (cf intermittent reinforcement) •Shaping
Dollard and Miller 1950
Inner stimuli can be reinforcing •Habits
•Primary drives and reinforcers
•Secondary drives and reinforcers
SLT - BANDURA
Bandura (1978, 1989)•Expanded from just behaviour to consider cognitions as well
•Forethought (Bandura 1999) – we can conceptualise the outcomes of our behaviour
•Modelling (Bandura and Walters, 1963) – affected by characteristics of the model (e.g. similarity), attributes of the observer (e.g. confidence), consequences of the behavior
•Self-efficacy (Bandura 1989, 1994, 2012)•Self-reinforcement (linked with forethought)
Rotter 1982 LOC
Locus of control
•Behaviour potential = reinforcement value X expectancy
•Internal vs External LOC
- Culpin et al (2015) – deprivation > ELOC > depression
- Bender (1995) – repeated failure at school > ELOC
Attachment - Bowlby 1982
) – innate attachment system (seeking closeness with parental figures) vs e.g. exploration system. Activated in the presence of threats and aims to seek safety, protection and comfort. Assessed e.g. in infants in the Strange Situation (Ainsworth, 1991