All in the mind’s eye

Has anyone ever let their imagination run away with them? For example, we recently had a problem with moths in our house, and for a while afterwards, I was convinced I could see moths everywhere. Luckily, I'm not going mad, as researchers from Vanderbilt University in the US have now proved that what you see with your 'mind's eye' might have a direct impact on what you see back in reality. This is the first study to show that imagining something changes your vision both while you are imagining it and afterwards. 

To test how imagination affects perception of reality, the scientists asked people to imagine simple patterns of vertical or horizontal stripes. They then showed the volunteers a green horizontal stripey pattern to one eye and a red vertical stripey pattern to the other. This situation is difficult for the brain to process, so a person will tend to see each the images switching back and forth. 

But in this case, the scientists found that people who had been thinking of vertical stripes were more likely to see the vertical striped pattern, while those who thought of horizontal stripes were more likely to focus on those.  The team also found that showing volunteers a faint picture of either horizontal or vertical stripes before the experiment could also influence which pattern they saw in the test.

Although these are quite simple experiments, they suggest how imagining previous experiences, or expectations, might actually influence the things you see. And the team found that rather than needing to imagine something many times, just one thought could have an impact, under the right conditions.

The results of the study provide a new way for scientists to objectively measure how strong an individuals mental imagery might be, and how much it affects their perception of reality.  So it could be a useful tool for studying the imagination - a topic that's very hard for researchers to investigate.