Blood, sweat, and the influence of others: The effect of descriptive norms on muscular endurance and task self-efficacy

• An experimental design is used to examine the effect of descriptive norms on muscular endurance and task self-efficacy.
• Descriptive norm messages result in greater performance of an objectively-measured activity behaviour.
• Descriptive norms result in greater task self-efficacy compared to control.

ObjectivesThe primary purpose of this study was to examine the influence of descriptive norm information about others' performance on muscular endurance (plank hold). A secondary purpose was to examine whether descriptive norms could serve as a vicarious stimulus informing task self-efficacy.DesignUsing an experimental design, adults were randomly assigned to either a descriptive norm (DN; n = 34) or control (n = 34) condition.MethodsParticipants performed two maximum endurance planks separated by a rest period. Immediately after performing the first, all participants completed a task self-efficacy measure relating to the second plank. Following this, those in the DN condition received a verbal message stating that 80% of similar others held their second plank for longer than their first. Control received no message. Prior to performing the second plank, all participants completed the efficacy measure again.ResultsResults from two ANCOVAs revealed that those in the DN condition held their second planks for significantly longer (controlling for plank 1 time), F (1,65) = 17.99, p < .001, ηp2 = .22, and reported significantly higher task efficacy (controlling for pre-message task efficacy), F (1,65) = 35.08, p < .001, ηp2 = .35, than those in the control condition.ConclusionsResults extend previous research by relating descriptive norms to a new objective activity, while controlling for past behaviour, and by finding a causal relationship between descriptive norms and task self-efficacy for a muscular endurance task.