Researchers from around the world are actively exploring means to identify observable markers that provide insights into the cognitive processes occurring within our minds while we contemplate various issues and make decisions. Their aim is to uncover a method for investigating the concealed operations of the mind by tracking subtle physiological signals originating from the body.
Recent research stemming from experiments conducted at Tohoku University have unveiled a connection between eye movements and specific forms of decision-making. Kazumichi Matsumiya and Shota Furukawa, affiliated with the Graduate School of Information Sciences at the university, have published their research findings in the journal Communications Biology.
"Our work has revealed that eye movements that are not related to the visual requirements for decision-making are nevertheless affected by the process of making decisions," says Matsumiya. Previous research in the field has analyzed how eye and hand movements affect decision-making, but did not look at the issue from the other direction to investigate if decision-making affects eye and hand movements.
The study aimed to evaluate the validity of a previously held general assumption suggesting that motor movements, such as those involving the eyes or hand, would remain unaffected by decision-making processes when these movements were not directly tied to the decision itself.
To conduct this investigation, researchers from Tohoku University directed participants to execute eye and right-hand movements toward targets unrelated to an ongoing perceptual decision-making task. Initially, participants were assigned a distinct task in which they had to determine and report the direction of movement of a brief visual stimulus displayed on the screen. This task was classified as a perceptual decision-making exercise.
Subsequently, participants engaged in a task where their eye and hand movements held no relevance to their decision-making process. By comparing the outcomes of these two tasks, the research team was able to detect and quantify any impacts of decision-making on eye and hand movements that were unrelated to the decision itself.
"We found that perceptual decision-making interfered with unrelated eye movements but not hand movements," Matsumiya says. "This demonstrates that nerve signals involved in making decisions continuously flow into the oculomotor eye-movement system, even when multiple motor actions are irrelevant to the decision-making," he adds.
The researchers anticipate that their discoveries will play a pivotal role in the advancement of novel technologies designed to deduce the progression of decision-making processes within the mind, even in scenarios where the decision-making does not entail any eye movements.
This development holds promise for enhancing fundamental research aimed at gaining insight into the internal cognitive processes of individuals, achieved through indirect monitoring of the occurrence or absence of decision-making events.
Furthermore, these findings have the potential for practical applications, particularly in the context of monitoring attentiveness during critical tasks that involve substantial decision-making. This application could be valuable in various domains, including mental health care support, dementia care support, and crime prevention initiatives.
Kazumichi Matsumiya et al, Perceptual decisions interfere more with eye movements than with reach movements, Communications Biology (2023). DOI: 10.1038/s42003-023-05249-4