# Sex Differences in Children's Motivation and Action Patterns for Climbing as Behavioral Relicts of Ancestral Sexual-Size Dimorphism

## TL;DR

This paper explores how boys and girls differ in their climbing behavior, suggesting these differences may be linked to evolutionary traits related to ancestral sexual size dimorphism.

## Contribution

The study provides empirical evidence of sex differences in climbing motivation and action patterns among children.

## Key findings

- Girls aged 3-6 had fewer climbing-related injuries than boys, but this reversed between ages 7-10.
- Girls were more likely to climb playground structures than boys, especially as they aged.
- Girls climbed differently on rock walls, with high classification accuracy based on sex.

## Abstract

Four studies investigated sex differences in children's motivation and action patterns for climbing playground structures and a gymnasium rock wall to assess any influence of ancestral sexual-size dimorphism limiting tree-climbing agility. Study 1 examined yearly incidences of children aged 3 to 13 falling from monkey bars and jungle gyms in a 1985–1989 National Electronic Injury Surveillance System dataset. Injury incidences of 3- to 6-year-old girls were lower than those of same-aged boys with the inverse occurring between ages 7 through 10 (p < 0.001). Study 2 determined that, during two recess periods in 13 elementary schools, 3.14% of enrolled girls were climbing playground structures compared with 1.45% of enrolled boys (p = 0.021) who were less inclined to climb as they aged. Study 3 showed that 6 to 8 year-old girls climbing alone perched longer (p = 0.0004) on 3 jungle gyms in a regional park longer than same-aged boys. Extended perching by girls might reflect their greater desire for surveillance useful historically for assessing danger. For Study 4, video recordings were made of the climbing actions of 28 children 7- to 12- years of age enrolled in an indoor rock-wall climbing class for beginners. Girls exhibited marked climbing differences (p = 0.005), with discriminant function analysis classifying 84.6% of girls correctly and 86.7% of boys correctly. While tree climbing was not studied directly, the sex differences shown in these studies indicates that girls are motivated to climb playground structures more than boys and climb rock walls using different action patterns.