Hasset et. al. (monkey toy preference) AICE Psych AS

What are sex differences in toy preference based on?

Nature/nurture debate

Research findings among boys and girls has shown:

•Boys tend to interact with masculine-type toys (e.g. wheeled trucks) as girls tend to favor feminine-type toys (e.g. stuffed animals)
•Boys tend to stick to stereotypical masculine toys as girls will play with a range of masculine & feminine toys
•Studies looking at bio differences among boys & girls point to the notion that girls with CAH (congenital adrenal hyperplasia) producing more androgen favor masculine toys even with stereotypical upbringings

What was the previous monkey study mentioned about?

•Previous study with Vervet monkeys (Alexander & Hines

What does Hasset argue with about the previous study?

•Hassett et al. argues that this did not display toy preference itself among nonhuman primates

Overall Purpose

•Overall, to investigate potential sex differences among Rhesus monkeys for toy preference

Aims

•To investigate if toy preference is related to biological factors rather than socialization
•To compare the toy preference of male and female Rhesus monkeys to previous research findings for human children

Hypothesis

•Toy preference among sexes is due to biological causes (that influence behavioral and cognitive biases) rather than learned differences

Type of study

Natural Field Experiment

IVs

•(a) sex of monkey (natural IV)
(b) category of toy- wheeled (masculine) or plush (feminine)
(c) rank & age of monkey (natural IV)

DVs

•(a) frequency of playing with toy
(b) duration of playing with toy
(c) magnitude of preference score

Design of the study

•Independent groups
•(a) gender of monkey
•(b) one exposure to each available toy (one truck was repeated)

Sampling Technique

•Opportunity sample from Yerkes National Primate Research Center
•Via Emory University in ATL

Participants

•N= 82… 61 females & 21 males met the criteria for the study
•Sample chosen from a large social group of 135 that have lived there for 25+ years
•14 excluded b/c of participating in other prenatal hormone study & 39 babies excluded as it was too difficult to tell them apart in observations
•Monkeys were pre-coded for social rank & age (used for later data analysis)
•Social rank was previously determined by behavioral observations of grooming

Apparatuses

•Available toys were categorized by object properties rather than traditional gender assignments
•The colors and shapes of the items varied

Procedure

•Subjects were housed were their natal (birth) group in a 25m x 25m outdoor compound that had a temperature-controlled interior area also

•Subjects were kept in the enclosed area while researchers placed one wheeled and one plush toy in the outside area

Behavioral Checklist

•Extended touch
•Hold
•Sit on
•Carry in hand
•Carry in arm
•Carry in mouth
•Drag
•Manipulate part
•Turn entire toy
•Touch (like poke)
•Sniff
•Mouth (put to)
•Destroy
•Jump away from
•Throw

Results:Frequency Data

•FREQUENCY DATA
•Each monkey received their own 'data set' for frequency and duration of behavior(s) with the toys
•Not all individuals interacted with a toy (no data for them)
Those with less then 5 recorded behaviors were not used for data analysis (14 males & 3 females)
•Frequency data showed the following:
Within the sexes:
*Males showed a statistical preference for wheeled toys over plush toys (9.77:2.06)
*Females did not show a statistical preference between the two categories of toys (6.96:7.97)
Comparing the sexes:
Females interacted with the plush toys more

Results: Duration Data

•Within the sexes:
•Males showed a statistical time spent playing with wheeled toys over plush toys (5mins: 30secs) •Females did not show a statistical difference among the toys (1 ½ each minutes on average) •Comparing the sexes: •No overall statistical difference was found b/w the sexes for the time spent playing with the wheeled and plush toys

Other Results:

•Magnitude of preference' score was calculated for all Ps (chart below)
•For males= total frequency/total duration w/wheeled toys - total frequency/duration w/plush toys
•For females= opposite (plush-wheeled toys as above)
•Results:
•*Males had a significantly higher preference for wheeled toys whereas females showed no strong preference
•Rank data
•Males did not show a correlation with rank (neither frequency or duration)
•Females showed (a) a positive correlation with rank for frequency of play for wheeled & plush toys and (b) positive correlation with duration only for plush toys
•Age data
•No differences were found

General Results

•Comparison of Rhesus monkeys to human children study (Berenbaum & Hines

Conclusions

•Hassett et al. note that their findings support a biological basis for differences in toy preference
•In both this study and the Berenbaum & Hines (1992) one

Ethics

•Study was met ethical guidelines while working with animals
•Study conducted in accordance with NIH Guide for the Care & Use of Laboratory Animals
•Took place at the Yerkes National Primate Research Center
•Approved by the Emory University Ethical committee on animal care and use
•Proper housing
•Lived in social/family groups (as in the wild) in large

Strenghts

•Standardized procedure with counterbalancing
•Counterbalancing
•Use of video cameras
•Use of inter-rater reliability
•Use of a set behavioral checklist
Consideration & data analysis of potential confounding variables of social rank & age

Weaknesses

•Only selected data used
•Comparing the monkey to human child data was not identical as the monkey toys were based on category (wheeled or plush) and the human data was on gender stereotyped toys
•Quan data only

Nature vs. Nurture Debate

•Nature support
•Findings provide evidence that biological differences (hormones) can play a main role in toy preference among the sexes among human and non-human primates
•In particular

Application to Everyday Life (Usefulness)

•May be helpful in choosing toys to give as gifts
•Can be helpful for toy makers and advertisers

Grave: Generalizability

LOWER= only certain data used
Study can't say that this is true for all monkeys or true for humans. (toy categories)

GRAVE: Reliability

Many CONTROLS and standardization allowing for replicability

GRAVE: Applicability

Applicability is high:
Perhaps this can help understanding male and female differences

GRAVE: Validity

They tested what was intended: "toy preference"

GRAVE: Ethics

More positive ethics …good housing and low distress