Hassett et al

• Sex stereotype toys


  Toys that are typically associated with a particular gender, e.g. Barbie for girls, trucks/dragons for boys
• Dr. Wallen and Janice Hassett worked together on a study to investigate whether monkeys would show a preference for sex stereotype toys
• Reese's monkeys


  • Generally more engaged in rough and tumble play than female monkeys, similar to human infants
• Aim of the study


  To test whether the toy preferences are due to biological factors or socialization
• Congenital adrenal hyperplasia


  An inherited condition where the fetus is exposed to high levels of prenatal androgens (male sex hormones)
• Play


  Getting pleasure from an activity
• Psychologists believe that play helps individuals practice skills required for adulthood, e.g. girls playing with dolls to prepare for caring for babies
• Differences between male and female brains


  • Different chromosome compositions
  • Different levels of sex hormones
  • Different cognitive processes
• Research has found that girls like playing with trucks more than boys like playing with dolls, but boys prefer trucks over dolls
• Nurture debate on toy preferences


  • Children learn toy preferences through gender and societal norms
  • In some cultures, girls are encouraged to play with dolls while boys are allowed to play outside
• Nature debate on toy preferences


  • Cognitive abilities depend on child's sex hormone levels
  • Biological factors like congenital adrenal hyperplasia influence toy preferences
• Previous research found that vervet monkeys preferred playing with male stereotype toys
• Research method


  Field experiment with controlled observations, correlational study using behavioral checklists, independent measures design
• Independent variable


  • Sex of the monkey (male or female)
• Dependent variable


  • Interaction with plush toys or wheel toys
• The original sample was 183 monkeys, but 53 were excluded due to being too young or previously involved in hormone research
• The final data included 34 monkeys (23 females, 11 males) who interacted with the toys on at least 5 occasions
• Procedure


  1. 7 trials of 25 minutes each in an outdoor enclosure

  2. Pairs of toys (6 wheel, 7 plush) placed 10 meters apart

  3. Interactions recorded on video and coded using a behavior checklist
• Most monkeys did not interact with the toys at all, so data from only 17 monkeys who showed at least 5 behaviors was included in the analysis
• Male monkeys


  Played with wheel toys for longer than female monkeys
• Female monkeys


  Played with plush toys for longer than male monkeys
• Social rank


  Dominance of the monkey
• Higher ranking female monkeys


  Preferred plush toys more than lower ranking females
• Male monkeys preferred wheel toys, while female monkeys showed no preference
• The results were similar to the toy preferences of human children
• Strengths of the study


  • Followed ethical guidelines
  • Used operationalized behavioral checklists for reliability and validity
  • Used video cameras to increase validity
  • Collected quantitative data on toy interaction duration
• Weaknesses of the study


  • Standardized procedure was abandoned when a monkey tore a toy
  • Potential observer bias as researchers were familiar with monkeys' genders
  • Lack of adult male monkeys in the sample reduced generalizability
  • Low ecological validity as monkeys were in captivity and never exposed to toys before
• The findings supported the nature-nurture debate, with social rank and biological factors like testosterone influencing the toy preferences