New Science Result: Even Stimuli We Aren't Aware of Can Affect What We Perceive

A paper out this week in the journal Current Biology includes a result that could be of interest to those who are interested in high-end audio. It's important to note, however, that the phenomena explored here are visual, not aural, so, while there tend to be similarities in how information from different sensory systems are processed, one should not automatically assume that the results apply to aural phenomena as well.

Learning to Use an Invisible Visual Signal for Perception shows that certain visual "percepts" can affect how we perceive other things, even if we aren't aware of them. Specifically, they used "a visual signal whose perceptual consequences were made invisible -- a vertical disparity gradient masked by other depth cues" to investigate how people responded to an image, in this case an image of a rotating cylinder. Participants were asked to identify the direction of rotation of the cylinder. The image could be controlled so that it could appear to be rotating in either direction -- or the apparent direction of rotation could be rendered ambiguous. The researchers found that when the direction was ambiguous, they could affect the perception of the direction of its rotation with invisible visual cues. "This approach excluded high-level influences such as attention or consciousness," they scientists write in a summary.

The phrase "invisible visual cues" sounds like an oxymoron, but apparently it isn't. These are cues that stimulate activity in the brain, but not conscious awareness. We see them, but we don't know we see them.

In a way, the result isn't so surprising. What I think it's saying is that you can alter the perception of a visual phenomenon by altering what we see in ways we are not consciously aware of.

If we assume this applies to aural phenomena as well (and I cannot rigorously justify such an assumption), it's easy to see how rich and difficult the task of critical listening is. It's fair to assume that it isn't just influences rigged in a laboratory that can have an effect. All sorts of influences we aren't aware of -- and I'm talking about perceptual cues and not marketing messages -- are likely to influence how we perceive things.