The impacts of co-representation and social facilitation on time perception in joint action

Previous studies have shown that time perception is a common phenomenon, but most time perception research focused on individual level and little is known regarding time perception in social contexts. To fill this gap, the present study combined a joint action paradigm with a time perception paradigm to investigate time perception in social contexts and further examine the mechanisms of co-representation and/or social facilitation in joint temporal perception through three experiments.In general, the study utilized a between-subject 2 x 2 experimental design, with the factors of context (individual vs. joint) and duration distribution (short intervals vs. long intervals). The stimulus durations were either 400 ms or 1000 ms for the short interval group, and 1000 ms or 1600 ms for the long interval group. The different intervals were filled with either yellow or green circles. Participants first completed a learning task alone and then were randomly assigned to either an individual or joint context and completed a practice task. In the joint condition, two participants not knowing each other practiced in different temporal intervals and completed the experiment together. In the individual condition, one participant sat alone on the left or right side of the screen and completed the experiment. During the learning phase, participants were familiarized with the short- and long-interval stimuli. During the practice phase, orange solid circles of different durations (ranging from 400 ms to 1000 ms, in steps of 100 ms) or green solid circles (ranging from 1000 ms ~ 1600 ms, in steps of 100 ms) were randomly presented on the screen. Participants judged whether the duration of the stimulus was "short" or "long" according to the criteria formed during the learning phase.The results of Experiment 1 showed that the joint condition had significantly higher temporal perceptual sensitivity compared to the individual condition in the long interval condition, but there was no significant difference in the short interval condition. Meanwhile, the joint condition demonstrated significantly higher temporal perceptual sensitivity compared to the individual condition, as evidenced by the higher Just Noticeable Difference (JND) and Weber Score in the joint condition. Experiment 2 and 3 manipulated the beliefs of the participants and the contents of the partners’ tasks, respectively. In Experiment 2, participants believed they were performing with a partner who was not actually present. The PSE in the belief condition was significantly lower than in the individual condition but not significantly different from the joint condition. In Experiment 3, participants were performing temporal tasks while their partners were performing nontemporal tasks. Results showed that the PSE was significantly higher than in the joint condition but not significantly different from the individual condition in Experiment 1.In summary, the present study demonstrates that co-representation and social facilitation have an impact on temporal estimation in joint temporal perception. Specifically, co-representation enables individuals to represent and integrate temporal information from both their own and their partners’ tasks as a priori information, resulting in a subjective temporal tendency to their partner’s tasks. On the other hand, social facilitation reduces attentional resources, resulting in a decrease in temporal perceptual sensitivity.