A co-actor's focus of attention affects stimulus processing and task performance: An ERP study

Gender composition of pairs influences joint action effect

Research on joint action has demonstrated that individuals are sensitive to a coactor's attentional relation to jointly attend stimuli. It has also been suggested that some features are necessary to resolve the discrimination problem (i.e., self-own and other-own actions). In the present study, we aimed to test whether the gender composition of interacting pairs modulated the joint action effect. Same- (female-female or male-male) and mixed- (female-male) gender pairs performed a joint version of flanker tasks in Experiment 1 (90 participants, 50% males), while in Experiment 2 (154 participants, 50% males) Navon tasks were performed. In Experiment 1, a higher joint flanker effect in same-gender pairs than in mixed-gender pairs, and this joint effect was similar to the classical flanker effect reported by males and females in a classical procedure of the task (70 participants, 50% males). In Experiment 2, the same-gender pairs reported a joint Navon effect, which was reversed in mixed-gender pairs. In conclusion, our findings support how the gender composition of interacting pairs plays a role in joint attentional tasks.

Color me impressed: A partner's target feature captures visual attention

Attending to a target is more difficult in the presence of a salient distractor. The present study investigated whether social value can modulate the extent to which distractors capture attention. Two participants sitting side-by-side performed a visual search task in cooperative and competitive conditions. Search displays contained either both targets, one target and a neutral stimulus or an ambiguous and a neutral stimulus. Results showed that agents took longer to respond to targets presented together with the partner's target compared to a neutral stimulus of equal salience. Agents also produced more false alarms in response to stimuli whose color lay between their own and the partner's target color compared to stimuli lying between the colors of their target and a neutral stimulus. These results suggest that stimuli with features relevant to a partner can capture attention more than neutral but equally salient stimuli, indicating that social value affects selective attention in a similar way as task goals and selection history.

Social information rapidly prioritizes overt but not covert attention in a joint spatial cueing task

Coordinating actions with others is crucial for our survival. Our ability to see what others are seeing and to align our visual attention with them facilitates these joint actions. In the present research, we set out to increase our understanding of such joint attention by investigating the extent to which social information would be able to prioritize overt (when moving the eyes to attend) and covert (when shifting attention without eye movements) attention in a joint spatial cueing task. Participants saw a cue and detected a target at the same or a different location alongside an unseen partner of either higher or lower social rank. In a novel twist, participants were led to believe that the cue was connected to the gaze location of their partner. In Experiment 1, where participants were told to not move their eyes (covert attention), the partner's social rank did not change how quickly participants detected targets. But in Experiment 2, where participants were free to move their eyes naturally (overt attention), inhibition of return effects (slower responses to cued than uncued targets) were modulated by their partner's social rank. These social top-down effects occurred already at a short SOA of 150 ms. Our findings suggest that overt attention might provide a key tool for joint action, as it is penetrable for social information at the early stages of information processing.

Influence of time-of-day on joint Navon effect

The shared attention theory suggests that people devote greater cognitive resources to those features co-attended simultaneously with others, determining better performance in several types of tasks. When co-actors performed a go/no-go Navon task attending different features of target letters, the performance was impaired, reflecting a joint Navon effect (the representation of a co-actor's attentional focus made it more difficult to select and apply one's own focus of attention), probably due to asynchronous co-attention with a decrease in cognitive resources involved. Researches in chronobiology and chronopsychology demonstrated that not only selective attention (involved in a Navon task), but also cognitive resources have a daily fluctuations, mainly paralleling the circadian rhythm of body temperature (i.e. increasing values from the morning to evening with a subsequent decline in the night). The study was conducted to assess whether the presence of joint attention, as measured by the joint Navon effect, was influenced by the time-of-day. Sixteen pairs of participants sitting next to each other were required to respond to the identity letters in a go/no-go Navon task twice: in the morning (09:00-10:00) and early afternoon (13:00-14:00). The results showed a joint Navon effect in the morning session only, suggesting that joint attention was affected by the time-of-day effect on cognitive resources.

Whose turn is it anyway? The moderating role of response-execution certainty on the joint Simon effect

When a two-choice "Simon task" is distributed between two people, performance in the shared go/no-go task resembles performance in the whole task alone. This finding has been described as the joint Simon effect (JSE). Unlike the individual go/no-go task, not only is the typical joint Simon task shared with another person, but also the imperative stimuli dictate whose turn it is to respond. Therefore, in the current study, we asked whether removing the agent discrimination component of the joint Simon task influences co-representation. Participants performed the typical joint Simon task, which was compared to two turn-taking versions of the task. For these turn-taking tasks, pairs predictably alternated turns on consecutive trials, with their respective imperative stimulus presented either on 100% of their turns (fully predictable group) or on 83% of their turns (response-uncertainty group, 17% no-go catch trials). The JSE was absent in the fully predictable, turn-taking task, but emerged similarly under the response-uncertainty condition and the typical joint Simon task condition where there is both turn and response-execution-related uncertainty. These results demonstrate that conflict related to agent discrimination is likely not a critical factor driving the JSE, whereas conflict surrounding the need to execute a response (and hence the degree of preparation) appears fundamental to co-representation.

Enhanced encoding of the co-actor's target stimuli during a shared non-motor task

Task co-representation has been proposed to rely on the motor brain areas’ capacity to represent others’ action plans similarly to one's own. The joint memory (JM) effect suggests that working in parallel with others influences the depth of incidental encoding: Other-relevant items are better encoded than non-task-relevant items. Using this paradigm, we investigated whether task co-representation could also emerge for non-motor tasks. In Experiment 1, we found enhanced recall performance to stimuli relevant to the co-actor also when the participants’ task required non-motor responses (counting the target words) instead of key-presses. This suggests that the JM effect did not depend on simulating the co-actor's motor responses. In Experiment 2, direct visual access to the co-actor and his actions was found to be unnecessary to evoke the JM effect in case of the non-motor, but not in case of the motor task. Prior knowledge of the co-actor's target category is sufficient to evoke deeper incidental encoding. Overall, these findings indicate that the capacity of task co-representation extends beyond the realm of motor tasks: Simulating the other's motor actions is not necessary in this process.

I've got your number: Spontaneous perspective-taking in an interactive task

Thinking about how other people represent objects in the world around them is thought to require deliberate effort. In recent years, interactive "joint action" paradigms have shown how social context can affect our cognitive processing. We tested whether people would represent their partner's point of view in a simple team game. Participants played a game in which they had to judge the magnitude of a number either sat alone, or opposite a partner. Importantly they were never asked to judge their partner's point of view. Remarkably, when playing the game as a team, people were better when their partner happened to share their view of the number, such as when seeing a number 8, than when their partner viewed the number to be different, such as when seeing a number 6 that looked like a number 9 to their partner. In two further experiments, we identified the conditions under which the effect was present. Experiment two showed that the effect was only present after observing the prior involvement of one's partner in the task. Experiment 3, showed that the aspect of the stimulus (its magnitude) that participants were sensitive to did not need to be the aspect of the stimulus to which their partner was paying attention.