Lecture 7 Flashcards
who performs better on a verbal task men or women?
female
who performs better on a spatial task, men or women?
men
which tasks favor men?
- visualisation- how an object will look when folded
- throwing accuracy
- spatial orientation
- visual interference
- mathematical reasoning
which tasks favour women
- peceptual speed- rapid matching of items
- object location memory
- word fluency
- fine motor coordination
- numerical calculation
within a meta analysis of men and women of all ages who scores higher on spatial abilities and what is the effect size of this?
men- small to medium effect
within a meta analysis of men and women of all ages who scores higher on mental rotation and what is the effect size of this?
men- medium to large effect size
within a meta analysis of men and women of all ages who scores higher on verbal abilities and what is the effect size of this?
women- so small that it can be considered not to exist
what is the subgroups of spatial ability and who performs better in these?
men
spatial visualisation, visual interference and mental rotation
what are the subgroups of verbal ability and which gender scores better in these?
women
comprhension, language and vocab
what are the biological variables for explainations of sex differences in intelligence?
- brain size
- maturity rates
- evolutionary perspectives (for spatial ability)
- hormones
explain how brain size effects general intelligence
- correlation between brain size and IQ=0.33
- correlation is even larger for females
- men have a 10% larger brain than women
explain how maturity rates effect general intelligence
Boys and girls mature physically and mentally at different rates
Boys and girls mature at the same rate up to the age of 7 years
Between age 8 – 15 years, girls mature faster (→ might explain why no differences among adolescents exist)
At the age of 16 onwards into adulthood, boys start to develop larger average brain size (→ sex differences in general intelligence start to develop)
what does Lynn’s 2004 data show on sex differences but how is this flawed
far fewer sex differences in adolescents and more in adults.
but…the sizes are v small to non-existent, suggesting only little support to her hypothesis.
Explain evolutionary perspective in terms of sex differences in spatial ability
- FORAGING- men took lead in foraging- need for spatial skills (finding way around, be able to hunt and intercept animals and hit targets)
- RANGE SIZE- females monogamous males are polygamous. to pursue and maintain multiple relationships men need to cover a wide area of land
- WARFARE- travel long distances to ambush other men- develop spatial awareness to fight well in new environments
what are ‘male’ hormones called?
androgens
what are ‘female’ hormones called?
estrogens
what is the most prominent androgen and what are female levels of this like?
testosterone (females produce about 10% of males)
what is the most prominent oestrogen?
oestradiol
what is the most prominent gestagen?
progesterone
how do steroids act differently from other hormones and what does this result in?
they can pass the lipid bilayer of a cell membrane- have direct access to the nucleus and gene expression.
how does testosterone cause sex differences in spatial ability?
- has organizing effects on the brain during prenatal development and has activation effects during life
- Hooven- higher levels of testosterone in males are significantly related to faster responses and lower error rates on a mental rotation task.
how can steroid hormones influence neurons?
-can quickly act (within seconds or less) to alter membrane excitability, sensitivity to neurotransmitters, or neurotransmitter release
→ by directing binding to and modulating the functions of, various enzymes, channels, and transmitter-receptors
2) Can diffuse across the outer membrane and bind to specific types of steroid receptors in the nucleus → promotes/ inhibits transcription of specific genes in the nucleus (takes mins to hours)
what steroid hormone influences the GABA receptor and what does this potentiate
progesterone
potentiates the amount of chloride activated by GABA
what are the effects of progesterone similar to?
the sedative and anticonvulsant of the benzodiazepine class of drugs.
what happens to the effects of steroid hormones through life?
can exert different effects during life
what are organizational effects
done in womb e.g. tissue development in irreversible ways
what are activational effects?
usually temporary effects of a hormone
give an example of how hormones and not chromosomes determine the sexual characteristics of the nervous system
when a cow carries two calves (male and female)-genetic male w/ female brain and vice versa
Female calve is exposed in utero to some testosterone produced by her male twin
→ Freemartin
Female calve will invariably be infertile and behave more like a bull.
talk about spatial abilities across the menstrual cycle.
women perform better during menses than in the midluteal stage
what is polycystic ovary syndrome?
an endocrine disorder associated with elevated levels of free testosterone
what do polycystic women demonstrate?
worse performance on tests of verbal fluency, verbal memory, manual dexterity, and visuospatial working memory than healthy control women.
no differences between groups were found on tests of mental rotation, spacial perception or perceptual speed.
what do women with elevations of testosterone show?
poorer performance on cognitive tests that show a female advantage.
what did evelated testosteone levels within boys predict? and was this found in women?
predicted average IQ (not gifted/ mentally challenged)
no difference in girls
why is human brain sex dimorphisms hard to prove in test replication?
→ sexual dimorphism is quite small
→ inter-individual variability is large
→ measurements techniques are often not sensitive enough
(especially when brain functions are measured)
→ brain locations and brain structures are not always obvious
→ sample size; availability of especially postmortem human brains
(matched for age, history, health, etc.)
list general sexual dimorphisms within the cortex
→ cortex is larger in men than women (not the brain in general)
→ male cortex contains more neurons than the female cortex
→ women have a larger proportion of grey to white matter
→ absolute amount of grey and white matter in the cortex is higher in men
who observed that men have larger and heavier brains than women? however what is the issue with this?
Broca
Brain size and brain weight are rough measures (and don’t explain anything)
what are the methodological limitations to measuring fine brain structures such as number of eurons?
- ‘Uncountable’ large number of neurons (20 billion neurons in the neocortex)
- Estimating the number from a (much smaller) sample
- Postmortal shrinkage of the brain (makes it difficult to estimate)
how many neurons does the male brain vs female brain contain and give the % difference
Male cortex contains 22.8 billion neurons. Female cortex contains 19.3 billion neurons (difference of 15.5%)
from age 20-90 approx what % of all neocortical neurons are lost over life span in both sexes?
10%
what is the best determinant of total number of neocortical neurons?
sex and age
what doesn’t play a role on neuron number?
body size
what sex difference wasn’t consistent for all regions and all variables?
numerical density
what does the Planum teporale have a large overlap with?
wernicke’s language area (understanding language)
is the left or the right planum temporale bigger in 65% of humans
left
what regarding the planum temporale is reduced in women?
hemispheric asymmetry of the planum temporale
what regarding the planum temporale is greater in women?
dimorphisms in cytoarchitecture. women reveal higher density of neurons in layer II and VI
what have several studies claimed sexual dimorphism about the corpus callosum?
the posterior part is selectively larger in women
the splenium is more bulbous and thicker in women than in that of men
what is suggested biologically as an explaination as to why there are sex differences in spatial ability
- differing amounts of grey matter and white matter
- hemispheric asymmetries.
what is white matter responsible for?
information transmission
what is grey matter responsible for?
information processing
what sides of the brain do men and women use for mental rotation tasks?
men use right side- men process this info better in the right hemisphere
women use both
what are environmental explainations for sex difeferences in Intelligence?
-gender stereotypes–> stem from schema and operate automatically
what did swim categorize as his three stereotypes for sex differences?
- overemphasised
- underemphasised
- accurate
what are overemphasised stereotypes?
the estimated size of the sex difference for the variable was greater than the real sex difference on that variable)
→ Example: We overemphasize how aggressive men are
what are underemphasised stereotypes?
the estimated size of the sex difference for a variable was smaller than the real sex difference on that variable)
→ Example: We underemphasize men’s helping behaviour in an emergency
what are accurate stereotypes?
., the estimated size for the sex difference for the variable is the same as the real sex difference on that variable)
→ Example: We may be accurate in terms of viewing men as being more restless
what is stereotype threat?
A social-psychological threat that arises when one is in a situation or doing something for which a negative stereotype about one’s group applies
… it is a situational threat … it can affect any group about whom a negative stereotype exist …”
what is empiracal support for gender stereotype threat?
steele
A social-psychological threat that arises when one is in a situation or doing something for which a negative stereotype about one’s group applies
… it is a situational threat … it can affect any group about whom a negative stereotype exist …”
what experiment shows stereotype threat in black and white participants?
Black Stanford University student’s intellectual ability:
Test was given- if pariticipants were asked to record race on questionaire before test
salience of racial stereotype alone was enough to depress the performance of black students.
what acts as empirical evidence for both gender and race stereotype threat?
asain-american women
if before ethnic identity was activated they performed better
if before gender identity was activated they performed better.
performed to the stereotype that was predicted of them
what did smith and white show about males and asian stereotype threat?
1st done on women
then on white men
Explicit- activated stereotype (men are better/ asians are better)
- Nullified- men/women= same or white/asian=same
- implicitly- just given test with nothing else stated.
when given a negative stereotype where is brain activation in women?
- brain regions associated with emotional load
- orbital and medial frontal gyrus
- rostral anterior cingulate
- fusiform gyrus
- superior parietal lobule
when given a positive stereotype
-increased activation in brain regions associated with visual processes.
- middle temporal gyrus
- ventral portions of anterior PFC and cingulate gyrus
when looking into a psychobiological approach to cognitive sex differences what was tested?
Tests: Five sex-sensitive cognitive tests (paper-pencil tests) Stereotype questionnaire Self-expectancy questionnaire Mood Scale
Hormones:
Chemiluminescence Assay
- Saliva testosterone
- Saliva estradiol
what were the results from the psychobilogical approach to sex differences?
Can imagine abstract objects and rotate them mentally in all directions: Significant sex difference in gender-stereotypes when all participants are included (p = .003)
Can Generate many words beginning with the same letter in one min: bSignificant sex differences in self-ratings p < .01
based on stereotypes what happened to testosterone production?
Hausmann et al.
men produced more than control group
females produced less than control group
