Choosing to help others at a cost to oneself elevates preschoolers' body posture

Young children sometimes help others at a cost to themselves, but little is known about the emotional mechanisms underlying this behaviour. Here, 5-year-old children (n = 96, 45 girls, mean age = 5.57 years, SD = 1.79 months, range = 5.19 years to 5.9 years, families recruited from a local database based in a medium-sized German city) were engaged in one task and then asked either to help (child-helps) or watch (child-watches) an adult complete another task. Children would lose (cost) or not lose (no-cost) the progress they had made on their own task if they engaged with the adult. Children were more likely to interrupt their own task in the helping condition and were overall faster to do so when helping was not costly. Children who chose to incur a cost to help showed more positive emotions after helping-as measured via changes in their postural elevation-compared to helping at no cost. This pattern was not found in the child-watches condition. This suggests that costly helping holds emotional rewards for children in ways that non-costly helping does not.