# Zooming in on Early Aggression: A Cross‐Cultural and Developmental Study of Youth in the United States and Aotearoa New Zealand

## TL;DR

This study compares specific types of aggression in young children from the U.S. and New Zealand to better understand patterns and inform early interventions.

## Contribution

The study provides new insights into age and gender differences in specific acts of aggression in early childhood across two countries.

## Key findings

- Physical aggression rates remained consistent across ages and grades in both U.S. and New Zealand samples.
- Boys showed higher rates of physical aggression than girls, but gender differences in relational aggression varied between the two samples.
- Aggression acts requiring cognitive and verbal skills increased with age.

## Abstract

There is ample evidence supporting developmental differences in overall rates of both physical and relational aggression. However, research evaluating developmental trends in specific acts of aggression across measures is limited, particularly in early childhood. A better understanding of what specific acts of aggression are more common in early childhood could inform assessment and identify specific behavioral targets for early prevention and intervention efforts. The current study advances extant literature by examining teacher reported rates of specific acts of aggression in samples of early childhood youth from United States and Aotearoa New Zealand. Specifically, in the U.S. sample (N = 322, 56.5% male), differences in rates in specific acts of physical and relational aggression (and gender differences) were compared across preschool, kindergarten, and first grade. To further evaluate specific acts of aggression in early childhood, the New Zealand sample (N = 200, 51.5% male) examined age differences in preschoolers (2‐, 3‐, 4‐, and 5‐year‐olds) on acts of aggression delineated by both form (physical and relational) and function (proactive and reactive) as well as gender differences. Utilizing different measures, findings indicated that while acts of aggression that require more cognitive and verbal skills occurred at high rates among older youth, overall, percentages of physical aggression were consistent across ages/grade in both early childhood samples. Boys exhibited higher percentages of physical aggression than girls, as expected. However, gender differences in relational aggression were not consistent across the samples. Data from both countries support the importance of examining specific acts of aggression.