Do longitudinal studies support long-term relationships between aggressive game play and youth aggressive behaviour? A meta-analytic examination.

Aaron Drummond,Christopher J Ferguson,James D Sauer

doi:10.1098/rsos.200373

Abstract

Whether video games with aggressive content contribute to aggressive behaviour in youth has been a matter of contention for decades. Recent re-evaluation of experimental evidence suggests that the literature suffers from publication bias, and that experimental studies are unable to demonstrate compelling short-term effects of aggressive game content on aggression. Long-term effects may still be plausible, if less-systematic short-term effects accumulate into systematic effects over time. However, longitudinal studies vary considerably in regard to whether they indicate long-term effects or not, and few analyses have considered what methodological factors may explain this heterogeneity in outcomes. The current meta-analysis included 28 independent samples including approximately 21 000 youth. Results revealed an overall effect size for this population of studies (r = 0.059) with no evidence of publication bias. Effect sizes were smaller for longer longitudinal periods, calling into question theories of accumulated effects, and effect sizes were lower for better-designed studies and those with less evidence for researcher expectancy effects. In exploratory analyses, studies with more best practices were statistically indistinguishable from zero (r = 0.012, 95% confidence interval: −0.010, 0.034). Overall, longitudinal studies do not appear to support substantive long-term links between aggressive game content and youth aggression. Correlations between aggressive game content and youth aggression appear better explained by methodological weaknesses and researcher expectancy effects than true effects in the real world.

Highlights

Debates regarding the impact of aggressive video games on youth aggression have raged for decades, since the earliest cabinet and Atari 2600 console games
Over 100 experimental studies have been conducted on aggressive game effects, but recent scholarship suggests that publication bias led to overstated confidence in the short-term outcomes for aggression that could be reliably demonstrated [2]
We examined the following hypotheses: (i) aggressive game play will be related to youth aggression with effect sizes in excess of r = 0.10; (ii) studies with a greater number of best practices, such as those which employ standardized, clinically validated measures, independent ratings of video game content and carefully control for theoretically relevant third variables [29], will show greater effect sizes than studies with fewer best practices; and (iii) Effect sizes will increase with greater time lag in longitudinal studies, demonstrating the accumulation of effects over time

Summary

Introduction

Debates regarding the impact of aggressive video games on youth aggression have raged for decades, since the earliest cabinet and Atari 2600 console games. A little over two dozen longitudinal studies have examined relationships between aggressive game play and later aggressive behaviour among youth. Outcomes from these studies have been heterogeneous. Meta-analytic results suggest that effect sizes across studies are very low, typically less than r = 0.10 [8,9] How such small effects should be interpreted remains controversial, with some scholars proposing small effects are important in isolation or cumulatively over time [9], while others argue that small effects should not be interpreted as hypothesis supportive, given the high potential for misleading results owing to methodological noise [10]. Effect sizes may be reduced towards zero once important third variables are controlled [11] or effect sizes may become inflated owing to participant hypothesis guessing, or researcher degrees of freedom allowing scholars to reanalyse their results multiple ways to find best fits with their hypotheses, much as appeared to have happened with experimental studies [12]

Methods

Results

Conclusion