Arousal makes us more confident in what we perceive, study finds

New study found that even imperceptible changes in our state of arousal can influence the confidence we have in our visual experiences.

A team from University College London has found that subtle increases in arousal — even ones so slight we aren’t even consciously aware of — affect how confident participants felt about what they were seeing when asked to complete a simple task.

The team asked 29 volunteers to follow a cloud of moving dots on a screen, decide whether they were moving to the left or to the right, then rate how confident they are in their answer. Without the volunteers knowing, some of the challenges started with a disgusted face appearing on the screen — too briefly for the participants to consciously perceive it.

But their unconscious did pick up on the image, causing their heart rate to increase and their pupils to dilate. The team found that even when the dots were made noisier and harder to make out, participants in this aroused state maintained their confidence in the answers they were giving.

“Typically when we see something, we have insight not only into what it is that we’ve seen, but also how clearly we’ve seen it,” explains lead author Micah Allen from the UCL Institute of Neurology.