IF YOU ever felt paranoid about subliminal messages, you might be right to worry. Images we see but don鈥檛 consciously register have been shown to inform people鈥檚 decision-making.
Joel Voss of Northwestern University in Evanston, Illinois, and colleagues showed volunteers 12 kaleidoscope images for 2 seconds each while they also performed an unrelated number task to distract them from consciously committing the images to memory.
A minute later, volunteers were asked to look at pairs of similar-looking images and choose the one they had seen before. They were also asked whether they were sure, had 鈥渁 feeling鈥� they were right, or were just guessing.
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Those who took a shot in the dark were as successful as the rest. 鈥淭hey were 70 to 80 per cent accurate; it would be only 50 per cent if it was chance,鈥� says Voss (Nature Neuroscience, ).
During the memory task, the volunteers鈥� brain activity was monitored by electrical sensors attached to their heads. As the pattern of activity differed between 鈥済uessers鈥� and the other groups, it suggests that we access unconscious and conscious visual memories differently, says Voss.
