Does pupil dilation occur before insight?

As indicated by inspiration being referred to as an "aha moment" or a "Eureka moment," people perceive inspiration as a momentary event. However, a previous study reported on changes in a person's brain activity prior to them being inspired during a quiz that asked for a common word based on multiple different words. The present study investigated this further by conducting an experiment under the hypothesis that memory retrieval, which involves inspiration in object understanding, occurs in association with pupil dilation. As a result, it was found that the pupils of the experiment participants had dilated before they reported inspiration, which predicted inspiration thereafter. It is therefore believed that this discovery may lead to externally monitoring and controlling new strategies for memory retrieval in the future.

Lead author of the study and PhD student Yuta Suzuki explains that, "Most of the time, we are not conscious of our brain's activity. Perception and recognition are merely one part of total brain function, and there are many mysteries still left to solve with regard to this unconscious part of our brain that accounts for the majority of its activity. We decided to focus on people's object recognition and were able to use biometry to monitor the processing that occurs before a person is aware they have recognized an object. Even more surprising is the fact that a participant's confidence surrounding object recognition during a recognition task did not come into play. In other words, the pupil reacted regardless of whether the participant subjectively believed they were close to getting the answer, and we only tracked whether or not they answered that they recognized the object. We believe this suggests that successful memory retrieval of an object in subconscious processing is in fact reflected in pupil dilation."

Research team leader and Associate Professor Tetsuto Minami says that, "Up until now, we mainly researched 'inspiration' by measuring brain waves, but we can now expect new developments with combinations of different measuring techniques thanks to this new discovery using non-contact pupil measurement technology."

Associate Professor Tetsuto Minami further states that, "Being inspired by objects is deeply related to memory retrieval success. If we can, for instance, uncover a brain processing mechanism in which pupil dilation and problem solving based on inspiration are related in a different way, this could be used as an index when comparing healthy patients to patients with a cerebral function disorder (for example, patients on the autism spectrum and patients with schizophrenia). Externally controlling pupil dilation is also expected to help with both diagnosis and treatment if it can be used to promote cerebral processing."