Survival processing leads to social information hoarding

In shared tasks carried out with a partner, people often encode information related to their partner even when it is irrelevant to them. This social encoding may be especially adaptive in fitness-relevant situations, for example, when survival is at stake. In two experiments, we asked whether this joint encoding effect would be enhanced when the joint task was survival-related. In Experiment 1, using a survival processing paradigm combined with a joint encoding task, 47 university participants imagined themselves in either a survival or a moving scenario, alone or in dyads with a confederate. The participants and confederates rated the usefulness of words from different categories for their assigned scenario. A surprise recall test showed that participants in both groups recalled more items from their partner's category than items from the unassigned category. Crucially, this joint memory effect was larger in the survival group, suggesting that participants had superior encoding of the partner's information in the survival scenario. In a second experiment, we replicated this finding with a different sample of 50 university students and a confederate. These findings point to a "social information hoarding" strategy, where participants encoded as many items from their partner's category as those of their own when in a survival-related situation. The cognitive mechanisms underpinning such a social information hoarding strategy require further investigation.