A deliberate delay: Using slower movements as a cooperative signal in a face-to-face game.

Previously (Ma et al., 2023), we showed that when two players were cooperating during an online card game, they more successfully shared their intentions with each other. We also measured mouse movements, which revealed that cooperating pairs moved more efficiently, spending less time moving and moving more directly. Even though social interactions increasingly occur online, it remains unclear whether online interactions follow a similar format to in-person ones. In this study, we recreated the previously published online experiment (Ma et al., 2023) in a real-world context to determine whether individuals resolve and create social uncertainty similarly across physical contexts. Eighty-two participants (41 dyads) completed six card games, three cooperatively and three competitively. In each game, players collected cards that matched their goal and guessed what goal the other player was collecting. For each player, we measured card and guess scores (game performance), along with their hand kinematics. Similar to the online study, participants guessed the other player's goal more accurately during cooperation compared with competition (cooperate benefit), and performance improved across games (learning benefit). However, in the real world, player movement was opposite to previous findings, with participants moving slower and less directly when cooperating compared with competing. These differences in movement suggest that social decision-making behaviour is not just context dependent (e.g. competition or cooperation) but also environment dependent, with an in-person environment altering how individuals reduce and create uncertainty. (PsycInfo Database Record (c) 2026 APA, all rights reserved).