Mathias Pessiglione et al. repeatedly showed 20 subjects abstract symbols as they played a gambling game. Each symbol presentation involved one of three choices and was followed by a 'masking image' in a series that flickered so fast that the subjects could not consciously perceive the symbol shapes. The subjects were told that the symbols were associated with winning or losing, and then allowed to gamble.
The subjects won more than they lost, indicating that their brains recognized the unperceived symbols and learned to associate them with reward or punishment. Functional neuroimaging showed that the mechanism involves the ventral striatum (see figure), a brain area associated with assessing reward value.
Friday, October 03, 2008
It turns out that we can learn to assess risks on the basis of visual hints we are not aware of seeing. In other words, without conscious processing of contextual cues, our brains can learn their reward value and use them to provide a bias on decision making. Functional neuroimaging reveals a correlation of cue values and prediction errors with activity in ventral striatum during conditioning. From the summary in Nature: