Photo via flickr by h.koppdelaney
Neuroscientists have proposed a simple explanation for the pleasure of grasping a new concept: The brain is getting its fix.
The “click” of comprehension triggers a biochemical cascade that rewards the brain with a shot of natural opium-like substances, said Irving Biederman of the University of Southern California. He presents his theory in an invited article in an issue of American Scientist.
“While you’re trying to understand a difficult theorem, it’s not fun,” said Biederman, professor of neuroscience in the USC College of Letters, Arts and Sciences. “But once you get it, you just feel fabulous.”
The brain’s craving for a fix motivates humans to maximize the rate at which they absorb knowledge. Biederman hypothesized that knowledge addiction has strong evolutionary value because mate selection correlates closely with perceived intelligence. Only more pressing material needs, such as hunger, can suspend the quest for knowledge, he added.
The same mechanism is involved in the aesthetic experience, Biederman said, providing a neurological explanation for the pleasure we derive from art. “This account may provide a plausible and very simple mechanism for aesthetic and perceptual and cognitive curiosity.”
Biederman’s theory was inspired by a widely ignored 25-year-old finding that mu-opioid receptors—binding sites for natural opiates—increase in density along the ventral visual pathway, a part of the brain involved in image recognition and processing. The receptors are tightly packed in the areas of the pathway linked to comprehension and interpretation of images, but sparse in areas where visual stimuli first hit the cortex.
Biederman’s theory holds that the greater the neural activity in the areas rich in opioid receptors, the greater the pleasure. In a series of functional magnetic resonance imaging trials with human volunteers exposed to a wide variety of images, Biederman’s research group found that strongly preferred images prompted the greatest fMRI activity in more complex areas of the ventral visual pathway.