Why we shouldn't believe our eyes

The mind can play tricks on us

People really shouldn't believe everything they see, say scientists.

Studies have shown that people often "remember" saying or hearing things that were never actually said.

Now, a study in the United States has confirmed that they can also "remember" seeing things that were never there.

Researchers at Ohio State University suggested these so-called false memories occur much more easily than many people realise.

Slide show

Dr David Beversdorf and colleagues based their findings on a study of 23 young adults, all of whom had a clean bill of mental health.

Each volunteer was shown 24 sets of 12 slides. Each slide portrayed different geometric shapes, which varied in number, size, position, shape and colour.

Visual false memories can be induced pretty easily Dr David Beversdorf, Ohio State University

For instance, the volunteers were shown a set of 12 slides showing yellow triangles.

Each slide showed one, two or three large or small triangles. Multiple triangles were arranged either vertically or horizontally.

After studying each group of slides, the participants were shown an additional five slides and asked if they had seen any of the shapes in the original viewing.

Two of these had been shown before. However, the other three had not. Two of these looked very different to what had been shown before while the remaining slide looked slightly similar, what researchers termed the lure slide.

The volunteers correctly identified those slides they had seen 80% of the time. They also correctly identified the images that obviously weren't part of the original set of shapes 98% of the time. However, nearly 60% said they had also seen the lure slide.

"This suggests that visual false memories can be induced pretty easily," said Dr Beversdorf.

The findings were presented at the annual Society for Neuroscience conference in New Orleans.