Biological Level of Analysis

Biological Level of Analysis

1. #1 Behavior can be innate because it is genetically based

   • evolution plays a key role in behavior
   • mirror neurons
     • Gallese et al. 1996
       • isolate neural response in rhesus monkeys reaching for food When another individual reached for food, the neural response was still seen in the monkeys even though they weren't reaching for food
   • inheritance
     • Genes and DNA are passed from parents to offspring
     • twin studies
       • Minnesota Twin Study - Bouchard et al. 1990
         • Compared MZA's (monozygotic raised apart) and MZT's (monozygotic raised together) Cross-cultural validity - global study determines heritability estimate of 70% for intelligence
     • intelligence
       • Bouchard and McGue 1981
         • Found that closer the kinship, the higher the correlation for IQ --- individuals 100% genetic relationship but different nurture = any IQ similarity will be genetics
   • Darwin & natural selection
     • hormones
       • oxytocin
         • creates bonding within families and society -- evolutionary strength in community
       • adrenaline
         • causes flight/fight response  -- evolutionary survival
     • disgust

2. #2 Animal research can provide insight into human behavior

   • Martinez and Kesner 1991
   • humans share 93% of genes with rhesus monkeys
   • Gallese et al. 1996

3. #3 There are biological correlates of behavior

   • neurotransmission
     • method by which messages are sent throughout the body --- cause body to respond to stimuli
     • neuron - nerve cell axon - body of neuron neurotransmitters - cross synapses, stored in terminal buttons synapse - gab between neurons dendrites - receive information
     • acetylcholine
       • muscle contraction
       • Martinez and Kesner 1991
         • Aim: determine role of acetylcholine in memory rats were trained to go through a maze, some given shots to block acetylcholine Findings: acetylcholine important role in creating memory of maze
     • dopamine
       • voluntary movement, learning, and feelings of pleasure --- excess = schizophrenia
     • norepinephrine
       • arousal, alertness, and stimulation of the sympathetic nervous system
     • serotonin
       • sleep, arousal levels, and emotion
       • Kasamatsu and Hirai 1999
         • aim: how sensory deprivation affects the brain serotonin levels increased in monks' brains -- sensory deprivation triggered release of serotonin
   • hormones
     • oxytocin
       • mother-child attachment -- secreted by pituitary and hypothalamus
     • adrenaline
     • cortisol
     • testosterone & oestrogen
     • melatonin
       • SAD - seasonal affective disorder individuals are sleepy and lethargic because of an increase in melatonin --- genetically based explanation for behavior