Explaining overall outcomes rather than simply early childhood educations:

1

• Explaining overall outcomes rather than simply
  early childhood educations
• Why are there more men at the highest levels of
  achievement than women?
• Two possibilities from biological perspective
• Different average levels of ability
• Different variability

2

• Different averages easy to understand
• What about different variability?
• If men are more variable, will be more men
  represented at high and low ends

3

• Different averages not argued for frequently, but
  different variability still comes up
• Larry Summers (2005)

4

• Why greater variability?
• X-linkage exists for some diseases (hemophilia).
  Males more likely to get these diseases because
  only one gene must have, not two
• X-linkage of genes for intelligence would create
  greater variability
• 2 X chromosomes for women, 1 for men
• Greater variability with 1 result than with 2
• consider rolling dice

5

• 1 die 2 dice (mean)
• 1 16.6 3
• 2 16.6 13
• 3 16.6 34
• 4 16.6 34
• 5 16.6 13
• 6 16.6 3

6

• Problems with the idea of greater variability in
  intelligence
• Genes can cause diseases which make things go
  wrong (sickle-cell), but we dont know much about
  normal (or above-normal) genes
• How do genes affect positive development?

7

• Gender differences summary of Maccoby and
  Jacklin (1974)
• A number of unfounded beliefs and open questions,
  but also a set of well-established differences
• - Verbal ability
• - Visual ability
• - Math ability
• - Aggression

8

• Verbal ability differences
• Girls may talk earlier
• Girls may have better abilities

9

• Problems with differences
• Statistical significance vs. substantive
  significance
• Gender variability vs. overall variability

10

• Statistical significance vs. substantive
  significance
• Statistical significance is determined by a set
  of tests that determines the likelihood that a
  given observation is observed by chance
• In the social sciences, results are statistically
  significant when there is less than a 5 chance
  that they are due to random chance
• In medical science, statistical significance at
  .1 or less

11

• One of the key contributors to statistical
  significance is sample size
• With 200,000 subjects, an IQ difference of .02
  points would be highly significant
• Yet there is no substantive significance for this
  kind of result.
• Substantive significance whether the result is
  large enough to matter

12

• Gender variability and overall variability
• Meta-analysis to evaluate a number of studies
  that seemed to show sex difference
• Gender differences account for only about 1
  percent of variance in verbal ability suggests
  that other factors are much more important than
  gender.
• Is 1 percent substantively significant?

13

• Visual-Spatial Perception
• Again starting with Maccoby and Jacklins review
• Visual-spatial perception tests test subjects
  abilities to orient a lighted rod parallel to the
  floor in a dark room
• Some studies show gender differences, but
  relatively large numbers do not

14

• Visual-spatial perception
• Differences most likely to surface at later ages
• Gender variability is again small compared to
  overall variability
• 5 percent of variance can be explained by gender

15

• Variety of theories to explain these differences
• Brain size (seen as unimportant now)
• Sex-linkage
• Sex-linkage with sex-limited expression
  (androgens)
• Hemisphere specialization

16

• Sex linkage
• Basic version suggests that spatial ability is
  x-linked, producing greater variability in boys
  than in girls (and hence more high performers)
• Contradicted by XO individuals scores in math
  much lower than average

17

• Left-right brain hemisphere specialization
• Left hemisphere appears to carry out analysis,
  computation, sequential tasks
• Right half appears responsible for art, emotion
• Not originally applied to sex differences

18

• Specialized brains would be more efficient
• Thus, the hypothesis is that
• Men have specialized brains, womens are
  unspecialized
• No evidence to support these ideas
• Some difference in recall of right-ear vs.
  left-ear recall, but most show no sex differences
  again
• Studies show different approaches to nonverbal
  problem solving, but no sex differences in
  performance
• Finally, specialization results from experience
  (studies of language specialization in children)

19

• Overall variability
• Visual skills can be learned
• Gender differences in drafting which were
  initially evident disappeared over time
• The extent of independence and a lack of reliance
  on verbal interaction induces strong spatial
  skills
• Cross-cultural comparisons show
• No gender difference among Eskimos,
• Large gender differences among Temne

20

• Cross-cultural comparisons
• Show variability which contradicts biological
  determinism
• Also suggest certain types of characteristics
  (independence vs. discipline, amount of autonomy)
  that are highly suggestive of gender differences

21

• Non-biological explanations
• Mothers are more likely to repeat vocalization
  from a girl baby than a boy
• Mothers more likely to show male infants objects
  to manipulate
• Girls wear physically restrictive clothing
• Boys given more freedom and encouraged to explore
  more

22

• Math ability
• again, also a number of non-biological general
  explanations
• Perceived importance of math for future studies
• Perception of math as a male field
• Active discouragement by teachers and parents
• How to fix these problems?

23

• Adaptability of brain
• Kittens raised in environments without vertical
  lines will never learn to recognize them and walk
  into chair and table legs
• Brain structures continue to form after birth
  based on experiences

24

• Conclusions
• Are men smarter than women?
• - Fausto-Sterling no
• Do men and womens brains work differently?
• -Fausto-Sterling maybe, but differences are not
  substantively significant.

25

• Sociology of Science (dont write down)
• If all of the people involved in this accept
  scientific principles, how do they keep coming to
  different conclusions, and why do ideas which are
  wrong resurface?
• Fausto-Sterlings answer the level of proof
  needed depends on ones pre-existing beliefs
• Many of these ideas are easy to fit in with
  existing beliefs

26

• Fausto-Sterling notes that she is a developmental
  geneticist by training, but that she had
  experience in a variety of equal rights
  movements. (What about your instructor?)
• Another reason these occur
• Scientists are rewarded for doing something
  different
• Pressure to stick with an idea even if later
  evidence seems to contradict

27

• Standards of evidence to use
• Scrutiny received
• Peer-reviewed journals
• Dealing with alternate positions within work
• Appropriate citation of evidence
• Size of effects

28

• Nature of evidence
• Representativeness (for samples)
• Use of appropriate controls
• Appropriate experimental techniques
• Random assignment, blinding, sensitivity to
  observer effects
• Timing appropriate for causality
• Observational research in medicine and biology
  often is of worse quality than in the social
  sciences (personal opinion)

29

• Chapters 3, 4, 6
• Not assigned for the course
• Interesting
• 3 development of gender prior to birth,
• 4 PMS (primarily on the difficulties of
  definition and measurement),
• 6 rape (evolutionary and sociobiological
  discussions of)
• Not on exam

30

• Recap
• Sex differences
• real?
• Biological sources?

31

• Aggression
• The last of the major areas typically identified
  as a gender difference
• This difference typically relies on a hormonal
  explanation to support these ideas

32

• Types of evidence used to demonstrate biological
  sources of aggression
• Male overrepresentation in war, aggression
• Testosterone in humans
• Testosterone/ progesterone during development
• Testosterone in primates
• Testosterone in rats

33

• Male overrepresentation in war, etc.
• Men have typically been more involved in war,
  lynching, reckless driving, genocide, social
  dominance
• 2 problems
• Activities are socially constructed, involve a
  variety of forces other than pure biology
• Prevalence does not demonstrate biological source

34

• Testosterone in humans
• Fausto-Sterling claims no clear evidence that
  testosterone increases aggression in humans
• Many observational studies show no effect
• A 2001 review agrees that there is no firm
  evidence to support

35

• What about Steroids and Roid rage?
• Steroids are anabolic androgenic steroids
  (contain substances similar to testosterone)
• Typical results show that there these do not, in
  fact, produce aggression in users
• They may exacerbate aggression in those who are
  already hostile and competitive however

36

• Steroids J Clin Endocrinol Metab. 1996
  Oct81(10)3754-8
• Anecdotal reports of "roid rage" and violent
  crimes by androgenic steroid users have brought
  attention to the relationship between anabolic
  steroid use and angry outbursts.
• However, testosterone effects on human aggression
  remain controversial. Previous studies have been
  criticized because of the low androgen doses,
  lack of placebo control or blinding, and
  inclusion of competitive athletes and those with
  preexisting psychopathology.
• To overcome these pitfalls, we used a
  double-blind, placebo-controlled design, excluded
  competitive athletes and those with psychiatric
  disorders, and used 600 mg testosterone enanthate
  (TE)/week.
• Forty-three eugonadal men, 19-40 yr, were
  randomized to 1 of 4 groups Group I, placebo, no
  exercise Group II, TE, no exercise Group III,
  placebo, exercise Group IV, TE plus exercise.
  Exercise consisted of thrice weekly strength
  training sessions.

37

• The Multi-Dimensional Anger Inventory (MAI),
  which includes 5 different dimensions of anger
  (inward anger, outward anger, anger arousal,
  hostile outlook, and anger eliciting situations),
  and a Mood Inventory (MI), which includes items
  related to mood and behavior, were administered
  to subjects before, during, and after the 10 week
  intervention.
• The subject's significant other (spouse, live-in
  partner, or parent) also answered the same
  questions about the subject's mood and behavior
  (Observer Mood Inventory, OMI).
• No differences were observed between exercising
  and nonexercising and between placebo and TE
  treated subjects for any of the 5 subdomains of
  MAI. Overall there were no significant changes in
  MI or OMI during the treatment period in any
  group.
• Conclusion Supraphysiological doses of
  testosterone, when administered to normal men in
  a controlled setting, do not increase angry
  behavior.
• These data do not exclude the possibility that
  still higher doses of multiple steroids might
  provoke angry behavior in men with preexisting
  psychopathology.

38

• Testosterone during development
• AGS (andrenogenital syndrome exposed to high
  levels of male hormones during development) girls
  appear to be more tomboyish and aggressive
• This may be evidence of some effect, but suffers
  from problems

39

• Problems with AGS girls as evidence
• Lack of controls
• Observer bias
• Alternate explanations
• Other work on prenatal hormone exposure

40

• Lack of controls
• AGS patients receive cortisone, surgical
  correction
• Either of these could cause differences in
  behavior (particularly wakefulness, activity, and
  irritability)
• Controls would include children with cortisone
  or surgical correction without AGS

41

• Inadequate data collection
• Observer bias may strongly affect descriptions of
  behavior
• Baby X line of experiments show that observers
  identify similar behaviors differently based on a
  childs gender

42

• Alternate explanations
• Parents treatment of children may differ
  slightly (but enough) because of this difference
• AGS children also are likely involved in frequent
  hospital visits, and these may affect behavior

43

• Other work on prenatal hormone exposure
• June Reinisch found effect of exposure to female
  hormones (which should be converted into
  testosterone) on toy selection, aggresssion
• Other researchers found opposite effects of
  prenatal progesterone exposure.

44

• Testosterone in primates
• Injection of pregnant rhesus monkeys with
  testosterone
• Babies born with masculine genitalia despite
  being XX and displayed behaviors more similar to
  male monkeys
• Yet mothers behaviors in monkeys play a role in
  prompting gendered behavior
• Because the baby monkeys might appear male,
  mothers would treat differently

45

• Testosterone in primates
• No correlation between dominance in primates and
  testosterone levels

46

• Testosterone in other animals
• Testosterone in rats is clearly associated with
  aggressive behavior
• Yet there is great variability between different
  species female gerbils and hamsters are as
  aggressive as males
• Difficult to generalize across such different
  species

47

• Conclusion
• Biological literature offers little support for
  the idea that male hormones create differences in
  aggressiveness

48

• Other differences
• Brain structure presumably refers to the
  corpus callosum (the large part of the brain that
  connects the two hemispheres)
• Popular knowledge suggests that women have larger
  corpus callosums based off a 1982 Science
  article.

49

• More recent replications failed to uncover
  differences.
• 1997 review article by Bishop and Wahlstein
  (meta-analysis) "(t)he widespread belief that
  women have a larger splenium than men and
  consequently think differently is untenable.

50

• Make sure to read the sections on the corpus
  callosum and the hypothalamus.