Giving dyads the silent treatment: Anticipatory joint action and the need for external action feedback

Participants pressed computer keys to keep a moving dot stimulus within a rectangle, either alone or with a partner they could neither see nor hear. Pressing the A-key or L-key caused the dot to move right or left, respectively, for as long as the key was pressed. Switching between the A and L keys (i.e., turning) proved challenging: concurrently pressing both keys made the stimulus move upward, while pressing neither key made it move downward. Individuals performed better than dyads because they turned the dot near the edge of the rectangle and let it coast back and forth within the rectangle. Dyads turned the dot in the middle of the rectangle because they pressed their buttons as quickly as possible. These findings support the assertion that pairs require external feedback regarding the other’s actions during tasks necessitating anticipatory actions (Knoblich & Jordan, 2003; Van Der Wel, Knoblich, & Sebanz, 2011).