Handedness

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Lecture 11 Sex Differences 1. Sex differences
are subtle and best seen in large groups 2. Its
hard to find a good man nowadays (in
Psychology) 3. Hormones and cognition 4. Brain
differences?
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The most widely used standardized tests of
general intelligence have explicitly tried to
minimize sex differences in total score by
discarding those items that show the largest sex
differences in the normative sample and by
counterbalancing the number of remaining items
that favour either sex. This is true, for
example, of the Stanford-Binet and Wechsler
scales of intelligence. Such tests, therefore,
obviously cannot be used to answer the question
of whether there is in fact a true difference
between males and females in general
intelligence. Arthur Jenson (1980) Bias in
Mental Testing
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Studying biological sex differences is hard

• Debates are heavily politicisedshould women not
  become engineers?
• The file drawer problem 5 studies out of 100
  will find differences BY CHANCE..scientific
  journals are biased towards studies that find
  differences!
• Some sex differences are situation or
  experiment-specific
• Many sex differences are small and might be
  exacerbated by environment (dolls and Mechano.)

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• How to separate environmental effects (i.e.
  parental behaviours) from biological sex?
• very early differences..less likely to be
  completely environmental?
• boys raised as girls. girls raised as boys?
• cultural differences? (probably not much help)
• moderating effects of sex hormones in adulthood
  (i.e. changes across the menstrual cycle that are
  not mediated by mood or illness)

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• Sex specific hormones seem to play an organising
  role in very early life
• androgens steroidal hormones found in greater
  concentrations in males (i.e.testosterone)
• in mammals the absence of androgens in prenatal
  life results in development of female morophology
  (i.e. ovaries)
• lots of work on rats lordosis in males deprived
  of androgens or mounting behaviours in females
  given testosterone.the effects seem to last a
  lifetime .ORGANISING effects

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• The female male ratio in British Psychology UG
  programs is about 4 to 1.
• Why?
• Blokes like maths, engineering?
• Women see psychology as a helping profession?
• Women are more interested in relationships,
  communication, personality etc.?
• Women, more than men, fancy Ben Jones?

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1. Boys are defined in large part in terms of
their difference from girls, and so have to avoid
doing anything that is seen as the kind of thing
girls do. 2. Popular masculinity involves
hardness, sporting prowess, coolness, casual
treatment of schoolwork and being adept at
cussing, attributes which are regulated or
policed in peer culture. 4. The power of
certain images of appropriate masculinity often
militates against educational achievement by
making it difficult for boys to demonstrate an
interest in working towards school success.
Frosh, S., Phoenix, A., Pattman, R. (2003). The
trouble with boys. The Psychologist, 16, 84-7.
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Sex Differences in "Boys and Girls Are
Different" Perhaps one of the most interesting
sex differences shown on "Boys and Girls Are
Different" was research by Michael Lewis with
one-year old boys and girls. He had a barrier put
up, such that the child was separated from its
mother. The child could see the mother, but was
prevented from reaching her. Most boys tried to
knock down the barrier, but most girls just stood
there and cried. (italics added by
DPC http//www.theabsolute.net/misogyny/eisenman.h
tml
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While the Weinraub and Lewis monograph presents
some of this, what you are looking for is
Goldberg, S., Lewis, M. (1969). Play behavior
in the year-old infant Early sex differences.
Child Development, 40, 21-31. I hope this is of
help. Best, Michael Lewis Michael Lewis,
Ph.D. [phone] Phone University
Distinguished Professor [phone]
Fax Institute for the Study of Child
Development lthttp//www2.umdnj.edu/iscdweb/gt Rober
t Wood Johnson Medical School 97 Paterson
Street New Brunswick, NJ 08903
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• Goldberg, S. Lewis, M. (1969). Play behavior in
  the year old infant early sex differences. Child
  Development, 40, 21-31.
• 32 boys and 32 girls, 1 year old
• observational study---see through barrier
  separates child from mother after 15 mins.
• observer scores behavior with stopwatch

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• Cognitive sex differences in adulthood
• in most Western cultures, female male
  scholastic gap is wideningare females smarter?
• males may excel in some visuospatial tasks and
  in some mathematical skills
• females may excel in verbal and phonetic
  fluency, speeded articulation and fine motor
  skills
• how do you separate environmental pressures,
  sexism, socialisation etc. from biological
  differences in cognition?

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Hidden figures test spatial yet negligible sex
diff Surface development test spatial yet
negligible sex diffs
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Kimura, D. Hampson, E. (1994). Cognitive
pattern in men and women Is influenced by
fluctuations in sex hormones. Current Directions
in Psychological Science, 3, 57-61
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• Cognitive sex differences and hormones
• Hampson (1990) examined cognitive abilities
  across the menstrual cycle in university women
• alternate forms of same tests were used, matched
  for difficulty
• use of tests COUNTERBALANCED as most people
  improve the second time they take a test.
• found that women did better at verbal fluency
  and manual sill at mid-luteal phase, when they
  were worst at spatial tasks

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• Sex difference in the corpus callosum?
• De Lacoste-Utamsing and Holloway (1982)
• splenium (back part) more bulbous and larger in
  F splenial area and overall area relative to
  total brain weight greater in F
• several reviews disagree although many
  discrepancies in how you measure an irregular
  structure like the CC, let alone a part of it
  which is hard to demarck

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mswmaximum spenial width
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Simon Levay and others region of the
hypothalamus called SDN/POA (equivalent to a
nucleus in the rat AH/POA) may be larger in men
than women, and larger in straight men then in
gay men
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Byne (2001) Hormones and Behavior 40, 86-92. No
diffs between homosexuals and heterosexuals in
INAH3
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• Conclusions
• exaggeration by pro and anti sex difference
  camps are rifeyou need to read original sources
• some sex differences have a biological component
  to them..that doesnt justify sexism of any sort
• some sex differences are subtly biased by
  circulating sex hormonessuggests that they cant
  all be explained by environmental factors

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Next lecture Lecture 12 Summing up