Sex differences

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Sex differences

• Messinger
• Gender film clips
• Bonobo

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Sex differences

• What infant sex differences are described by
  Weinberg et al. find? How can biological factors
  and differential social expectations influence
  sex differences? Describe Maccobys theory of
  peer group sex-segregation and socialization.
  That is, how does children's peer play reflect
  and create gender differences? What is relational
  victimization? What is the male brain theory of
  autism? Describe empathizing and systemizing.

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Overview
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Biology's role

• Experiments with nonhuman primates show that
  administering testosterone to female fetuses late
  in gestation yields more typically masculine
  behavior.
• Placement of rat fetuses in utero influences
  sex-typed behavior
• Many sex differences are continuous, not
  categorical
• E.g. estrogen and testosterone

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Sex Differences in Early Infancy

• girls show stronger visual preferences for a
  doll (i.e., an object with human attributes) than
  for a toy truck
• (Alexander, Wilcox, Woods, 2009)
• boys shortly after birth show stronger visual
  preferences for a mechanical mobile than for a
  face
• (Connellan et al., 2000)

Alexander, G. M., Wilcox, T. (2012). Sex
Differences in Early Infancy. Child Development
Perspectives, 6(4), 400-406. doi
10.1111/j.1750-8606.2012.00247.x
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Feedback

• Between physical and social features

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Experience-independent sexdifferences in newborn
macaquesFemales are more social than males

• Simpson, Nicolini, Shetler, Suomi, Ferrari,
  Paukner (2016)

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Background

• Gender differences may be attributed to different
  evolutionary pressures
• Females primary caretakers
• increased social interests skills interpreting
  expressions ? increased offspring survival
• However, male and female human infants are
  treated differently from birth
• Parents handle male infants more rough spend
  more time in synchronous interactions with
  mothers
• Offer female infants more verbal stimulation
  get more parent-child interaction overall

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Current Study

• Nonhuman Primate Studies
• More control over experiences and environments
• Macaques have similar patterns in sex-related
  differences
• Goal assess sex differences in macaque infants
  raised in homogenous controlled environments
  (nursery)

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Methods
_

• 48 healthy, full term macaques (21 Female)
• Separated from mothers at birth
• Tested before exposed to social groups
• Eye tracking test at 2-3 weeks old
• Human interaction task at 4-5 weeks old

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Eye Tracking Task
_

• Across both measures there are main effects of
  sex
• Females look at faces longer regardless of
  expression than their male counterparts
• Females also specifically spend more time looking
  to the eyes and mouths of the face

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Human Interaction Task
_

• Sex differences only in Affiliative Social
  Behaviors
• Females significantly outperformed the males

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Take-homes

• First study to provide evidence for
  experience-independent sex differences in
  social behaviors soon after birth in any primate
  (humans included)
• Limitations
• No control stimuli
• Possible subtle differences in the way caregivers
  treated infants
• Disentangle social skills social motivation
• Questions?
• How do you feel about the procedures in both eye
  tracking task and human interaction task?
• Do you expect similar results if we could do this
  with human infants?
• Pre-natal environment differences?
• Did you buy it?

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Male newborns

• Less responsive to social stimuli
• less able to maintain eye contact
• Greater difficulties in maintaining affective
  regulation
• Smile less and display more irritability, crying,
  facial grimacing, and lability of emotional
  states
• more rapid buildup of arousal
• engage in less self-comforting
• Weinberg et al., p. 175

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Face-to-face
Boys Girls
Joy .26 .16
Interest .55 .68
Anger .07 .03
Look _at_ Mom .42 .35
Look _at_ Object .35 .45
Neutral/Positive Vocalizations .13 .06
Fussy Vocalizations .09 .04
(Weinberg et al.)
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Mothers more likely to

• talk to
• engage in face-to-face interaction
• hold and touch
• their male infants
• possibly in an attempt to soothe them

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Differential social expectations

• Pervasive TV, media
• Experimentally demonstrated
• Define normative expectations of everyday
  behavior and
• Define boundaries of acceptable behavior
• At the most intimate and the most mundane levels

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Biology and social environments jointly
influence gender development

• Direct socialization into gender roles by
  parents doesn't appear to be as singular an
  influence on children's sex-typed preferences and
  behaviors as once was thought, said Eleanor
  Maccoby.
• BY SIRI CARPENTER Monitor staff

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Maccoby

• "By and large, the daily routines of family life
  do not have much impact on the strong tendency of
  children to separate into same-sex groups, and
  probably not on the distinctive activities
  enacted by male and female groups," Maccoby said.

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Gender segregation

• Research on gender typing in individuals is
  inconclusive
• Clustering of gender-typed characteristics weak
• Relations to family characteristics weak
• Same-sex groupings predominate
• From 3 12,
• Cross-cultural phenomenon

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Martin and Ruble

• What age do infants understand gender?
• How stable are gender roles?
• Maccoby (2002)
• Longitudinal studies of gender role stability
• Studies suggest some level of stability
• Lack of longitudinal data with enough detail

Martin, C. L., Ruble, D. N. (2010). Patterns of
Gender Development Annual Review of Psychology
(Vol. 61, pp. 353-381). Palo Alto Annual Reviews.
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Constructivist argument

• Innate gender-specific proclivities
• Lead to same sex segregation
• Which creates gender-specific socialization
• Children create themselves playing with each
  other
• IS THIS POSSIBLE?

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Same-sex groupings

• Boys
• Larger groups
• More conflict/competition
• Cohesiveness
• More autonomous from adults

• Girls
• Smaller, more dyadic
• Less conflict, more responsive
• Less goal-oriented, more intimate

• Differential exposure to these groups influences
  individual behavior

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Sex differences

• With increasing age, boys and girls in preschool
  interact with members of the same sex
• (e.g., Fabes, Shepard, Guthrie, Martin, 1997
  Maccoby Jacklin, 1987 Martin Fabes, 2001).  
• By 4-5 years of age, both boys and girls are
  observed interacting with same sex peers at three
  to four times the frequency that they interact
  with other sex peers.

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Sex segregation at 5 years
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Day-to-day variability
Girls Boys
Same-sex preference
Other-sex preference
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Dynamic system approach to gender research

• Long term changes and short term interactions.

Lynn Martin, C., Fabes, R. A., Hanish, L. D.,
Hollenstein, T. (2005). Social dynamics in the
preschool. Developmental Review, 25(34),
299-327. doi http//dx.doi.org/10.1016/j.dr.2005.
10.001
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Example of Dyadic SSG
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Fig. 4A represents the state space pattern that
might be seen for a socially competent boy who is
solely attracted to other socially competent
children.
Fig. 4B illustrates a pattern based on sex
similarity. In this case, the events represented
on this boys state space illustrate that he is
seen interacting only with boys and it does not
matter what type of social behavior they tend to
display.
Fig. 4C depicts the landscape for a socially
competent boy whose state space is shaped by both
similarity on social behavior and on sex. The
events cluster in the region of socially
competent boys. If this pattern occurred, it
would suggest that behavioral similarity matters
but only in consideration for same-sex peers.
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Sex-Segregated Interactions
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Behaviorally Similar Interactions
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New approaches
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Child Mobility.ppt
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Digit Ratio (2D4D) and attachment styles in
middle childhood Indirect evidence for an
organizational effect of sex hormones

• Marco Del Giudice Romina Angeleri (2015)

Will M.
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Life history theory
How to make trade-offs between growth,
maintenance, and reproduction over the life
course given a limited amount of energy.

• Fast strategy mature early, reproduce early,
  have many offspring, invest less in them, die
  earlier
• E.g., Salmon
• Slow strategy mature late, reproduce later,
  have fewer offspring, invest more in them, die
  later
• E.g., Humans

Will M.
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Adaptive plasticity

• Individuals may adaptively speed up or slow
  down the default life history strategy based on
  cues of local conditions.
• BUT, not always just cues from early life
• Continuity in development is not always adaptive
• Continuity favored when
• a) Early and later conditions and tasks are
  congruent
• b) The metabolic costs of switching strategies
  is too high

Will M.
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Adaptive sex differences in attachment?

• No observed (or predicted) sex differences in
  early attachment
• Potential observed sex differences from
  adrenarche through middle adulthood
• Predictions
• Males insecurely attached become avoidant,
  switching to this orientation if necessary
• Female insecurely attached become ambivalent,
  switching if necessary
• Lets see why

Will M.
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Rationale for predictions

• Selection pressures differ between sexes, mostly
  for insecure individuals.
• Males paternity uncertainty no cap on
  reproduction low costs of conception less
  parenting effort, high intrasexual competition
  and thus more mating effort.
• Females maternity certainty cap on
  reproduction costs of pregnancy and lactation
  more parenting effort, choosier and thus less
  mating effort.

Will M.
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Adaptive significance

• Females
• Ambivalent orientation is useful for getting
  caregiving help from alloparents and male
  partners.
• Secure females do not need to waste energy on
  this.
• Avoidance orientation is good back-up strategy in
  extremely poor conditions
• wait-and-see orientation may be good in
  uncertain environments.
• Males
• Avoidant orientation is good (evolutionarily,
  not ethically) for motivating this strategy.
• Secure males are better off as dads than
  cads.

Will M.
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Does 2D4D digit ratio predict attachment in
middle childhood?

• Second digit typically shorter, but difference
  between lengths of the two digits greater in
  males than females.
• Rough-and-ready measure of early exposure to
  androgen and estrogen.
• Should predict differences in insecure attachment
  in both sexes

Will M.
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Procedure

• 285 Italian children, ages 8-11
• Digital scan of 2d4d
• Attachment measured with Coping Styles
  Questionnaire

Will M.
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Mean digit ratio higher in females

• Females score lower in avoidance, higher in
  ambivalence
• No sex differences in secure attachment
• More feminine ratios associated with less
  avoidance, more ambivalence, not felt security

Will M.
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Limitations, Questions

• Doesnt rule out social changes in middle
  childhood driving results
• 2d4d is not gold standard
• Controversy over measurement of attachment re
  finding sex differences
• Can you think of alternative explanations based
  on social changes in middle childhood?
• Thoughts on measurement?

Will M.
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Relational aggression

• attempts to harm the victim through the
  manipulation of relationships, threat of damage
  to them, or both (Crick et al, 02 p.98)
• Associated with internalizing/externalizing
  problems and later peer rejection
• Is relational aggression a cause for concern or
  part of everyday life?
• Will relational aggression be studied in 10
  years? Yes

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Provocation ? aggression

• Physically aggressive children exhibited hostile
  attributional biases and reported relatively
  greater distress for instrumental provocation
  situations
• Getting pushed into the mud
• Relationally aggressive children exhibited
  hostile attributional biases and reported
  relatively greater distress for relational
  provocation contexts
• Not getting invited to a birthday party.
• 662 third- to sixth-grade children
• Crick et al., 2002. CD.

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Aggression type and gender

• Boys more physically victimized by their friends.
  
• Friend physical victimization was particularly
  related to boys adjustment difficulties
• Girls more relationally victimized.
• Friend relational victimization was particularly
  related to girls adjustment difficulties.
• Crick Nelson, 2002.

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Prediction
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Cross-sex friendships

• Pre-school
• Elementary school
• Middle school
• High school / Adolescence

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Change

• 12th grade
• Boys 5 hrs a week w girls.
• Girls 10 hrs a week w boys.
• Larger network of other-sex friends increases
  odds of romantic relationship

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Changing functions of romance

• Adolescents mention affiliative features
• Adolescent romantic relationships are peer
  relationships
• Young adults mention trust support

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Extreme male brain theory of autism

• Baron-Cohen

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Empathizing (theory of mind)

• Empathizing is the capacity to predict and to
  respond to the behavior of agents (usually
  people) by inferring their mental states and
  responding to these with an appropriate emotion.
  

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Systemizing

• Systemizing is the capacity to predict and to
  respond to the behavior of nonagentive
  deterministic systems by analyzing
  input-operation-output relations and inferring
  the rules that govern such systems.

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Females and males

• At population level, females are stronger
  empathizers and males stronger systemizers.
• Eextreme male brain theory autism represents
  an extreme of the male pattern (impaired
  empathizing and enhanced systemizing).
• Specific aspects of autistic neuroanatomy may
  also be extremes of typical male neuroanatomy.

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You can be high in both or low in both

• Higher on graph more empathizing
• Lower less empathizing
• More to right higher systemizing
• More left less systemizing

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• Autistic people show lowest Empathizing
  (empathizing minus systemizing)

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AS/HFAgtMalegtFemale
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AS/HFAgtMalegtFemale
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Sex differences attenuated in ASD.
Baron-Cohen, S., Cassidy, S., Auyeung, B.,
Allison, C., Achoukhi, M., Robertson, S., Pohl,
A., Lai, M.-C. (2014). Attenuation of Typical
Sex Differences in 800 Adults with Autism vs.
3,900 Controls. PLoS ONE, 9(7), e102251. doi
10.1371/journal.pone.0102251
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Messinger, D. S., Young, G. S., Webb, S. J.,
Ozonoff, S., Bryson, S. E., Carter, A., Carver,
L., Charman, T., Chawarska, K., Curtin, S.,
Dobkins, K., Hertz-Picciotto, I., Hutman, T.,
Iverson, J. M., Landa, R., Nelson, C. A., Stone,
W. L., Tager-Flusberg, H., Zwaigenbaum, L.
(2015). Early sex differences are not
autism-specific A Baby Siblings Research
Consortium (BSRC) study. Mol Autism, 6, 32. doi
10.1186/s13229-015-0027-y

• What about the development of ASD?

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Relative risk of ASD 3.18
Relative risk of ASD Infant Gender and
Multiplex Status
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Sex by domain not affected by group

• Repetitive Behaviors

Social Affect
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Sex by subtestnot affected by group
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Conclusion

• Results are consistent with recent reports on
  gender effects among children with ASD at
  multiple ages, and comparisons to children with
  no ASD

• Sex differences in ASD prevalence
• No sex differences in overall symptoms or
  cognition
• Boys (higher RRB) and girls (higher language)
  with ASD differ in specific performance areas
• These sex differences exist in ASD, non-ASD,
  low-risk
• Results are consistent with recent reports
• Sex differences that appear in children with ASD
  may not be ASD-specific

• Sex differences in symptom domain and cognitive
  subtest

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Effect of female sibling

• Palmer, N., Beam, A., Agniel, D., Eran, A.,
  Manrai, A., Spettell, C., . . . Kohane, I.
  (2017). Association of Sex With Recurrence of
  Autism Spectrum Disorder Among Siblings. JAMA
  Pediatr. doi 10.1001/jamapediatrics.2017.2832

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Homosexuality as a Discrete Class

• Previous research on the latent structure of
  sexual orientation has returned conflicting
  results, with some studies finding a dimensional
  structure (i.e., ranging quantitatively along a
  spectrum) and others a taxonic structure (i.e.,
  categories of individuals with distinct
  orientations).
• The current study used a sample (N 33,525) from
  the National Epidemiologic Survey on Alcohol and
  Related Conditions (NESARC). A series of
  taxometric analyses were conducted using three
  indicators of sexual orientation identity,
  behavior, and attraction.
• Low-base-rate same-sex-oriented taxa for men
  (base rate 3.0) and women (base rate 2.7).
• Generally, taxon membership conferred an
  increased risk for psychiatric and substance-use
  disorders.
• Although taxa were present for men and women,
  women demonstrated greater sexual fluidity, such
  that any level of same-sex sexuality conferred
  taxon membership for men but not for women.
• Norris, A. L., Marcus, D. K., Green, B. A.
  (2015). Psychological Science. doi
  10.1177/0956797615598617

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Same-sex relationships

• Normative challenges in the context of
  disapproval/restriction
• Female gender identity / relationships
• Non-linear course
• Male gender identity / relationships
• More-linear course
• Same-sex and mixed-sex parenting indistinguishable

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Female Bisexuality From Adolescence to Adulthood
Results From a 10-Year Longitudinal Study. Lisa
Diamond

• 3 conceptualizations of bisexuality
• 1. Transitional phase
• 2. Third type of sexual orientation
• 3. Heightened capacity for fluidity
• Present study
• 79 non-heterosexual women
• 10 years, 5 assessment points. At each
• Label self sexual identity
• Lesbian, bisexual, unlabeled
• daily attractions that are same-sex
• of sexual contacts with men women (since last
  assessment)

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Identity

• Changing identity
• 73 of T1 bisexuals
• 83 of T1 unlabeled
• 48 of T1 lesbians
• More likely to switch between bisexual and
  unlabeled IDs than to settle on lesbian or
  heterosexual labels.
• 2/3 of ID changes adopting bisexual or unlabeled
  identity.
• identifying as bisexual or unlabeled
• T1 T2 T3 T4 T5
• 57 47 51 57 58

Bisexual and unlabeled women more likely to
change identity labels, ?2(2, N 79) 8.3, p lt
.02.
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Sexual Attractions

• Same-sex attractions declined significantly among
  lesbians only
• Women who gave up bisexual/lesbian IDs still
  reported bisexual patterns of attraction in T5

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Sexual Behavior

• Consistent decline in same sex behavior among all
  women
• NOT matched by a parallel decline in same-sex
  attractions
• By 2005, most women involved in long term
  monogamous relationships.
• 70 of T5 lesbians, 89 of bisexuals, 85 of
  unlabeled women, 67 of heterosexuals
• By 2005, 60 of T1 lesbians had had sexual
  contact with a man, and 30 had been romantically
  involved with a man
• Resolved by change in identity to
  bisexual/unidentified

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Discussion

• Bisexuality as stable pattern of attraction to
  both sexes, with balance varying based on
  personal and situational factors.
• Identity change more common than identity
  stability
• ID change reflects shifting experiences
• Adopt labels consistent with relationship status
• Seek to maximize fit with own prevailing pattern
  of attraction/behavior