No evidence of task co-representation in a joint Stroop task

Abstract

People working together on a task must often represent the goals and salient items of their partner. The aim of the present study was to study the influence of joint task representations in an interference task in which the congruency relies on semantic identity. If task representations are shared between partners in a joint Stroop task (co-representation account), we hypothesized that items in the response set of one partner might influence performance of the other. In Experiment 1, pairs of participants sat side by side. Each participant was instructed to press one of two buttons to indicate which of two colors assigned to them was present, ignoring the text and responding only to the pixel color. There were three types of incongruent distractor words: names of colors from their own response set, names of colors from the other partner's response set, and neutral words for colors not used as font colors. The results of Experiment 1 showed that when people were doing this task together, distractor words from the partner's response set interfered more than neutral words and just as much as the words from their own response color set. However, in three follow-up experiments (Experiments 2a, 2b, and 2c), we found an elevated interference for the other response-set words even though no co-actor was present. The overall pattern of results across our study suggests that an alternative response set, regardless of whether it belonged to a co-actor or to a non-social no-go condition, evoked equal amounts of interference comparable to those of the own response set. Our findings are in line with a theory of common coding, in which all events-irrespective of their social nature-are represented and can influence behavior.

Is Your Color My Color? Dividing the Labor of the Stroop Task between Co-actors

“…The Stroop effect for the actor's own target colors or for the coactor's target colors was no different from the Stroop effect for the non-target colors. Given that the semantic gradient has been one of the key findings in Stroop interference, this outcome was unexpected, but the lack of the differences in the Stroop effect for the actor's own target colors and the co-actor's target color is consistent with the finding of Saunders et al (2018). With nearly twice as large sample size as in Experiment 1, the results of Experiment 2 also showed no evidence that the semantic gradient occurred in RT.…”

“…As noted by Saunders et al (2018) Another interesting outcome of the present experiment was that, in RT, the Stroop effect was larger for the joint task than for the individual task. Apart from the fact that the task was performed by one actor or two actors, a difference between the individual and joint task settings in the present experiment is that the target colors in the individual task were DIVIDING THE LABOR OF THE STROOP TASK 14 always the actor's own target colors (i.e., go trials), whereas the target colors in the joint task were either the actor's own target colors (go trials) or the co-actor's target colors (nogo trials).…”

“…Hence, the present design provided a stronger test of task co-representation in a joint Stroop task than Demiral et al's. The second study by Saunders et al (2018) study was similar to the present study, but a main difference was that all types of distractor words were intermixed within a single block in that study. The present study separated the three types of distractor words (own target color, co-actor's target color, and non-target color) into different blocks because Levin and Tzelgov (2016) reported that the semantic gradient was observed only when different distractor words were separated between blocks.…”

“…The outcomes are consistent with the division of labor, but the discrepancy with the RT results made it difficult to consider this finding to be DIVIDING THE LABOR OF THE STROOP TASK 18 conclusive. Saunders et al' (2018) Hence, the generalizability of the results to vocal response should be tested in future investigations.…”

“…It is worth noting two recent studies that also used a joint version of the Stroop task (Demiral, Gambi, Niuwland, & Pickering, 2016;Saunders, Melcher, & van Zoest, 2018). In the first study by Demiral et al (2016), the main purpose was to compare individual and joint task conditions in terms of the ERP signal.…”