Social offloading: When joint action leads to cognitive facilitation

Sharing a task in the real world can be more efficient than doing it alone. However, psychology experiments using shared task paradigms have often revealed a cognitive cost from working together. Research on joint action has shown how people track and prioritise the actions and intentions of task partners even when this generates cognitive interference and impairs performance. In contrast, we present four experiments using the picture-word interference (PWI) task in which joint action removed cognitive interference and facilitated performance. In the standard PWI task performed alone, participants respond to target pictures while ignoring distractor words written on top. If picture-word pairs are related (e.g., apple-orange) then responses are slowed compared to when they are unrelated (e.g., apple-book), known as semantic interference. In our joint version of the task, we removed semantic interference by telling participants they would be collaborating with a partner who was responsible for the distractor words (Experiment 1, N = 77). Furthermore, interference was only removed when participants believed that their partner was responding specifically to the words (Experiment 2, N = 78), was perceived as high in social status (Experiment 3, N = 80), or high in task competence (Experiment 4, N = 76). We propose this demonstrates how people can deprioritise information associated with partners on shared tasks. In doing so, they can reduce their own cognitive demands by leveraging the cognitive resources of others to support an efficient division-of-cognitive-labour. We term this social offloading.