A study has found that even when things that signify a "reward" are actually not important at all, they are still powerful enough to capture people's attention.
A team of neuroscientists at Johns Hopkins, led by Steven Yantis found that test subjects who were completing a visual search task were distracted when items that had previously been associated with small amounts of money occasionally appeared.
Yantis, professor and chair of psychological and brain sciences in the Krieger School of Arts and Sciences said the results have implications for understanding how the brain responds to rewarding stimuli, which may contribute to the development of more effective treatments for drug addiction, obesity and ADHD.
In the study, people first searched for red or green circles in an array of many differently coloured circles displayed on a computer screen.
One colour (for instance, red) was always followed by a monetary reward (10 cents) and the other (perhaps green) by a smaller reward (1 cent).
After doing this for more than an hour, the study subjects then were asked to search for particular shapes (for instance, a circle among diamonds) and colour was no longer relevant or rewarded.
Still, occasionally, one of the items in the display was red or green. When that happened, the study subjects' responses slowed down.
According to Yantis, this proved that an overwhelming number of people in the study became distracted by the red or green objects, even though the study subjects had been instructed to ignore those items and the items were inconspicuous and had no relevance to the task at hand.
"It was clear to us that those red or green items had become valuable to the study subjects, because they were linked in their minds with a reward," Yantis stated.
The paper has been published this week in the Proceedings of the National Academy of Sciences.