Publication year
2017
Citation Title
Sex differences in non-verbal and verbal abilities in childhood and adolescence. Intelligence, 64, 81-88.
Journal Name
Intelligence
Journal Volume
64
Page Numbers
81-88
DOI
10.1016/j.intell.2017.07.007
Summary
Individuals' cognitive abilities can have implications on the quality of their task performance and social behaviors (e.g., verbal communication). Examining differences in cognitive abilities across the sexes can help to better understand the patterns of cognitive development. This study investigated sex differences in cognition by exploring nonverbal and verbal abilities across development in a sample of twin siblings. The findings indicate that sex differences in verbal and nonverbal abilities exist, with distinct variations from ages 2 to 16 years.
Key Findings
Females performed better than males at verbal and nonverbal communication at age 2, 3, and 4 years old. However, there were no gender differences in nonverbal ability at ages 7, 9, 10, 12, 14, and 16 years old.
Males performed better at nonverbal communication at ages 10 and 12 years old. However, there were no gender differences in verbal and nonverbal ability at ages 14 and 16 years old.
There was no difference in verbal or nonverbal abilities between females with male co-twins and females with female co-twins from ages 2 to 16 years old.
Implications for Military Professionals
Examine ways to create positive and personalized relationships with the children facing difficulties in establishing age-appropriate bonds
Facilitate collaborations with community partners to help provide youth with skills to strengthen verbal and nonverbal abilities
Implications for Program Leaders
Host classes for children and youth that aim to improve their verbal communication skills
Engage youth in small group activities that promote healthy interpersonal communication
Implications for Policy Makers
Continue to support the programs that explore differences in communication patterns across diverse school and after-school settings
Recommend the development of curriculum for training professionals on how to identify children who have difficulty in verbal and nonverbal communication with their peers and parents
Methods
Data were obtained from Twin Developmental Study (TEDS), an ongoing longitudinal study of twin pairs born in the United Kingdom between 1994 and 1996.
A range of psychological test were used to measure verbal and nonverbal abilities such as the MacArthur Communicative Development Inventories, Parent Report of Child Ability, picture Completion Test, Wechsler's Intelligence Scale for Children, Raven's Standard Progressive Matrices, and the Mill-Hill vocabulary scale.
Analysis was done to assess sex differences in nonverbal and verbal abilities across development. Additional analysis was done to explore if females with male co-twins outperform females with female co-twins on verbal and nonverbal abilities.
Participants
Participants were twin pairs born in England and Wales between 1994 and 1996.
The range of the sample size was between 14,187 (at age 4 years) and 4,959 (at age 16 years).
Participants who had significant medical or mental conditions, early birth complications, and those who did not speak English as their first language were excluded from the study.
No racial/ethnic or gender information about the participants was included in this study.
Limitations
The demographics of participants (e.g., gender or race/ethnicity) was not reported, which limits the generalizability of findings.
Tests used to measure verbal and nonverbal abilities differed in content measurements at different time points. This could have impacted result interpretation of differences in male and female cognitive abilities.
The sample size dropped significantly throughout the course of the study. This could have impacted the result interpretation of differences in male and female cognitive abilities, because those who remained in the study may be different from those who withdrew, or left the study.
Avenues for Future Research
Replicate the study with participants who represent diverse racial and ethnic groups and gender identities
Collect physiological data (e.g., MRI activity during task completion) to measure verbal and nonverbal abilities across life span
Gather data on youth outcomes associated with different verbal and nonverbal abilities, such as peer relationship satisfaction or job performance
Focus
Civilian
Target Population
Population Focus
Abstract
Twin research has shown that females with male co-twins perform better than females with female co-twins on mental rotation. This beneficial effect of having a male sibling on spatial ability could be due to in-uterine transmission of testosterone from males to females (the Twin Testosterone Transfer hypothesis, TTT). The present study explored sex differences and the TTT in non-verbal and verbal abilities in a large sample of twins assessed longitudinally at 2, 3, 4, 7, 9, 10, 12, 14 and 16 years of age. Females scored significantly higher than males on both verbal and non-verbal abilities at ages 2, 3 and 4. Males scored significantly higher than females on verbal ability at ages 10 and 12. The effect sizes of all differences were very small. No sex differences in non- verbal or verbal abilities were found at 7, 9, 14 and 16 years of age. No support for the TTT was found at any age. The findings indicate that the twin testosterone transfer effect occurs only for specific cognitive abilities, such as mental rotation.
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