6 - BRAIN AND (SEXUAL) BEHAVIOUR

Question 1

basic assumptions:

• all complex behaviour depends on processes in the brain
• the processes a brain can perform depends on its structure (mediate biological processes)
• systematically different structures give rise to systematically different processes results in systematically different behaviours

(not very accurate in relation to gender differences - see other cards)

Answer 1

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Question 2

what is a systematic brain difference?

Answer 2

not due to chance or context

• behaviour is stable
• across cultures and time
• found globally
• cannot really be proven (only suggests)

Question 3

statements:

if two groups differ systematically in their behaviour - suggests corresponding differences in their brain structure

systematic differences in male and female behaviour (sexual) suggest systematic differences in male and female brains (specifically parts controlling sexual behaviour)

but environment shapes brain (neural plasticity) so differences might be due to environment - cannot experimentally test in humans

IN A QUESTION IS MUST STATE ASSUMED THAT THERES GENDER DIFFERENCES ETC

Answer 3

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Question 4

information:

common assumptions on gender differences are based on self report

• could be bias
• some women may not feel appropriate to report honestly (maybe only small %)
• some men may exaggerate

mainly based on anglo-americans
- large intercultural differences in sexual behaviour

Answer 4

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Question 5

mating behaviour - SDN POA in rats

Answer 5

• sex specific movements and postures during mating
• SDN-POA larger in males
• controls male typical sexual behaviour

EMPIRICAL EVIDENCE
- male sexual activity increases firing rate is SDN-POA neurons
- electrical stimulation triggers male sexual behaviour
- volume of SDN-POA correlates directly with level of sexual activity (known via castration and testosterone therapy)
- treat female rat embryos with androgens:
= SDN-POA develops to male size (organisational effect)
= male typical sex behaviour as adults (only after androgen therapy - activational effect)

Question 6

courtship behaviour - HVC in songbirds

Answer 6

• singing is sex-specific (male typical) behaviour to attract females
• songbirds brains = area much larger in males
• HVC = area controlling song production

EXPERIMENTAL EVIDENCE
- treat female hatchlings with sex hormones (androgens in bloodstream or estrogens into brain)
= HVC develops to male typical size (organisational)
= singing behaviour male typical
= but only after androgen therapy (activational effect)

Question 7

sex differences - animals v humans

Answer 7

• in most animals, sexual behaviour is automatic - triggered by specific signals (eg female rat who just reached peak estrogen levels)
• controlled by lower brain areas (brainstem, midbrain, hypothalamic nuclei (SDN-POA)) - empirical evidence = electrical stimulation of these areas
• relatively sex specific behaviours (eg lordosis)
• relatively uniform within each sex (eg songs within a species - very small diff between individuals in a species)
• but evidence for social learning!
• in higher primates - sexual behaviour is even less automatic
  = less sex specific
  = less uniform within each sex (more variety)
  = more under control of higher (ie cortical) brain areas
  ASSUMPTIONS ^ (primates)

Question 8

potential areas of human cognitive sex differences

Answer 8

VISUOSPATIAL SKILLS
X - women better at memory?
X - men better at mental rotation?
- males slightly higher in high scores
- then concluded that men have better spatial skills
- but large overlap in skills
- say difference in DISTRIBUTION of scores
- in the high scores, more are men than women

MOTOR SKILLS
X - women better at hitting near targets? (fine motor skills)
X - men better at hitting far targets? (gross motor skills)
- maybe due to upper body mass?
- no causation

VERBAL SKILLS
X - women have better verbal fluency and language acquisition?
- no causation

LEFT-HANDEDNESS

• ‘men are more left handed than women’ = sweeping conclusion - not accurate
• of the left handed people, more are men
• something systematically different in the brain

ARE THESE DIFFERENCES REAL?

• very small!
• large role of culture, socialisation and learning
• difference has been reducing over time
• often context / experience dependant (eg men playing more video games / women doing better if experimenter is women)
• potentially instruction dependant (conditions to overthink affect female performance)
• environment changes (eg more chemicals now then before)
• handedness and language development = differences seem stable and similar across different cultures

Question 9

statement:

a women having sex with a man and a female bonobo having sexual intercourse with a male are NOT ACTIVATIONAL EFFECTS OF SEX HORMONES

Answer 9

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