What we evaluate, not just what we see, shapes pupil responses
Our pupils become smaller under brighter conditions and larger under darker conditions. In addition to responding to changes in light, pupil size is influenced by attention, emotion and how visual objects are perceived.
A recent study has revealed that pupil responses are influenced not only by the visual characteristics of everyday objects, but also by what observers are evaluating about those objects. Researchers from Toyohashi University of Technology examined how different evaluations, such as assessing an object's glossiness or attractiveness, affect the timing of pupillary responses.
To investigate this, 24 participants viewed images of 60 everyday objects for three seconds each while their pupil diameter was recorded. The images were carefully controlled for luminance characteristics, ensuring that only the evaluative aspects of the objects varied. Participants rated each object on separate 7-point scales for glossiness and attractiveness.
The findings showed that higher ratings for glossiness were associated with greater pupil constriction approximately one second after an image appeared. In contrast, higher ratings for attractiveness tended to be linked with greater pupil dilation later on. By employing advanced statistical techniques, the researchers were able to demonstrate that the relationship between ratings and pupillary responses varied systematically by task and over time.
The study's lead author, Hideki Tamura, explained that these results suggest that our evaluations of surface properties, such as glossiness, and impressions, like attractiveness, can impact pupil responses with different timing. This discovery has significant implications for understanding how our minds process visual information and the factors that shape our sensory experiences.
Moving forward, the research team plans to explore other material and surface properties, such as transparency, roughness, and softness, to further investigate how different perceptual and emotional evaluations manifest in pupil responses. This research sheds new light on the complex relationship between visual perception, evaluation, and physiological responses, paving the way for future studies in this fascinating field.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
