An interesting small Belgian study (n = 38, 20 females) by researchers from the VUB & the KU Leuven with Kobe Desender as first author tells you were to sit if you want to think really hard: next to someone who is also giving a mental effort!

How did they found out?

To investigate this, we adopted a variant of the Simon task in which two persons jointly perform the task. In a regular Simon task, one participant responds to the color of patches (e.g., blue or red) with either the left or the right hand, while ignoring its location on the screen (i.e., left or right). Typically, reaction times (RTs) are shorter and error rates lower on congruent trials, where the (task-irrelevant) location triggers the same response as the (task-relevant) color, compared to incongruent trials, where both features trigger a different response (i.e., the congruency effect). Here, two participants (A and B) are seated next to each other and each responds to half of the stimuli. For example, A responds to blue stimuli, whereas B responds to red stimuli.

Ok, but than they tweaked the Simon task a bit… In two experiments, two participants (A and B) jointly performed a Simon task, and the researchers selectively manipulated the difficulty of the task… but only for participant A.

E.g.:

But participant A is not the important one to check, participant B is. The researchers noted that participant B gave more mental effort when participant A performed the difficult version of the task, compared to the easy version. So the researchers conclude:

In the current study, we showed for the first time that the exertion of mental effort is contagious. Simply performing a task next to a person who exerts a lot of effort in a task will make you do the same.

Abstract of the study:

The presence of another person can influence task performance. What is, however, still unclear is whether performance also depends on what this other person is doing. In two experiments, two participants (A and B) jointly performed a Simon task, and we selectively manipulated the difficulty of the task for participant A only. This was achieved by presenting A with 90% congruent trials (creating an easy task requiring low effort investment) or 10% congruent trials (creating a difficult task requiring high effort investment). Although this manipulation is irrelevant for the task of participant B, we nevertheless observed that B exerted more mental effort when participant A performed the difficult version of the task, compared to the easy version. Crucially, in Experiment 2 this was found to be the case even when participants could not see each other’s stimuli. These results provide a first compelling demonstration that the exertion of effort is contagious.