In new research, scientists evaluate how our senses interact to aid our perception of the world.

Researchers discovered that the interplay and interaction among senses is complex but important. The intricacy is especially pronounced in regards to perception of moving objects as hearing and sight are deeply intertwined.

In fact the connection is so profound that even when sound is completely irrelevant to the task, it still influences the way we see the world.

“Imagine you are playing ping-pong with a friend. Your friend makes a serve. Information about where and when the ball hit the table is provided by both vision and hearing,”said Ladan Shams, Ph.D., senior author of the new study.

“Scientists have believed that each of the senses produces an estimate relevant for the task (in this example, about the location or time of the ball’s impact) and then these votes get combined subconsciously according to rules that take into account which sense is more reliable.

“And this is how the senses interact in how we perceive the world. However, our findings show that the senses of hearing and vision can also interact at a more basic level, before they each even produce an estimate.

“If we think of the perceptual system as a democracy where each sense is like a person casting a vote and all votes are counted (albeit with different weights) to reach a decision, what our study shows is that the voters talk to one another and influence one another even before each casts a vote.”

“The senses affect each other in many ways,” said cognitive neuroscientist and co-author Dr. Robyn Kim.

There are connections between the auditory and visual portions of the brain and at the cognitive level. When the information from one sense is ambiguous, another sense can step in and clarify or ratify the perception.

Now, for the first time, researchers have shown behavioral evidence that this interplay happens in the earliest workings of perception—not just before that logical decision-making stage, but before the pre-conscious combination of sensory information.

The study, said Kim, should add to our appreciation of the complexity of our senses.

“Most of us understand that smell affects taste. But people tend to think that what they see is what they see and what they hear is what they hear.”

The findings of this study offer “further evidence that, even at a non-conscious level, visual and auditory processes are not so straightforward,” she said. “Perception is actually a very complex thing affected by many factors.”

The new study appears in the December issue of Psychological Science.

Source: Association for Psychological Science