Interference in the shared-stroop task: a comparison of self- and other-monitoring

Co-acting participants represent and integrate each other’s actions, even
when they are not required to monitor one another. However, monitoring the
actions of a partner is an important component of successful interactions,
and particularly of linguistic interactions. Moreover, monitoring others
may rely on similar mechanisms to those that are involved in
self-monitoring. In order to investigate the effect of monitoring on
shared linguistic representations, we combined a monitoring task with the
shared Stroop task. In the shared Stroop task, one participant named the
colour of words in one colour (e.g., red) while ignoring stimuli in the
other colour (e.g., green); the other participant either named the colour
of words in the other colour or did not respond. Crucially, participants
either had to provide feedback about the correctness of their partner’s
response (Experiment 3) or did not (Experiment 2). The results showed that
interference was greater when both participants responded than when they
did not, but only when partners provided feedback. We argue that feedback
increased joint task interference because in order to monitor their
partner, participants had to represent their target utterance, and this
representation interfered with self-monitoring of their own utterance.