Eyes might miss, but brain sees everything

A new study has revealed that people can plan strategic movements to several different targets at the same time, even when they see far fewer targets than are actually present.

A team of researchers at the Brain and Mind Institute at the University of Western Ontario took advantage of a pictorial illusion — known as the “connectedness illusion” — that causes people to underestimate the number of targets they see.

Connecting the circles creates the illusion of fewer circles on the right. But when our brain plans actions to these targets it computes the actual number of targets. When people act on these targets, they can rapidly plan accurate reaches that reflect the actual number of targets.

Using statistical techniques to analyse participants’ responses to multiple potential targets, the researchers found that participants’ reaches to the targets were unaffected by the presence of the connecting lines.

Thus, the “connectedness illusion” seemed to influence the number of targets they perceived but did not impact their ability to plan actions related to the targets. These findings indicate that the processes in the brain that plan visually-guided actions are distinct from those that allow us to perceive the world.

“It’s as though we have a semi-autonomous robot in our brain that plans and executes actions on our behalf with only the broadest of instructions from us” said lead researcher Jennifer Milne.