Background Previous research has shown that children engage in greater physical risk taking when in an elevated positive mood state. The current study examined whether exposure to a peer-communicated behavioural norm about safety could counteract this effect.

Methods Community recruitment resulted in a sample of 120 children (7 to 10 years), including 60 boys (M age = 8.13 yrs; SD = 0.93 yrs) and 60 girls (M age = 8.02 yrs; SD = 0.91 years). Children’s intentions to engage in risk taking (based on identifying from photos which risky playground behaviours they would do if they had to make a videotape later that day) and actual risk behaviours (based on how they behaved when running through an obstacle course that contained hazards) were measured while in a neutral and positive mood state, with positive mood induced experimentally via false positive feedback during the playing of a novel videogame (emotion ratings throughout the session validated the positive mood induction worked; there was a significant increase in positive mood, as expected, t(119) = 15.12, p < .001). Before completing the risk taking tasks when in a positive mood state, children were exposed to either a peer-communicated behavioural norm about safety or a non-norm communication; this exposure occurred by the child overhearing two children supposedly talking next door (this was actually an audiotaped recording).

Results Exposure to the non-norm communication had no effect on risk taking: children showed an increase in risk taking and intentions when in a positive aroused mood state compared to a neutral mood state (M change = +0.65 standardised RT score), F(1, 59) = 71.31, p < .001, η_p ² = 0.55. In contrast, exposure to the peer-communicated behavioural norm about safety was effective to counteract this effect: children actually showed a significant decrease in risk taking and intentions when in a positive compared to neutral mood state (M change = −0.47 standardised RT score), F(1, 115) = 84.77, p < .001, effect size η_p ² = 0.42. Both risk taking measures yielded the same effects.

Conclusion Manipulating children’s exposure to peer-communicated behavioural norms can be an effective strategy for reducing injury-risk behaviours.