The brain's reward for “getting” a concept is a shot of natural opiates
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 the latest 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, he said.
"I think we're exquisitely tuned to this as if we're junkies, second by second."
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. (The data from the studies are being submitted for publication.)
Biederman also found that repeated viewing of an attractive image lessened both the rating of pleasure and the activity in the opioid-rich areas. In his article, he explains this familiar experience with a neural-network model termed "competitive learning."
In competitive learning (also known as "Neural Darwinism"), the first presentation of an image activates many neurons, some strongly and a greater number only weakly.
With repetition of the image, the connections to the strongly activated neurons grow in strength. But the strongly activated neurons inhibit their weakly activated neighbors, causing a net reduction in activity. This reduction in activity, Biederman's research shows, parallels the decline in the pleasure felt during repeated viewing.
"One advantage of competitive learning is that the inhibited neurons are now free to code for other stimulus patterns," Biederman writes.
This preference for novel concepts also has evolutionary value, he added.
"The system is essentially designed to maximize the rate at which you acquire new but interpretable [understandable] information. Once you have acquired the information, you best spend your time learning something else.
"There's this incredible selectivity that we show in real time. Without thinking about it, we pick out experiences that are richly interpretable but novel."
The theory, while currently tested only in the visual system, likely applies to other senses, Biederman said.
Net of a large number of social and demographic factors, more intelligent children grow up to be more nocturnal as adults than less intelligent children.
Compared to their less intelligent counterparts, more intelligent individuals go do bed later on weeknights (when they have to get up at a certain time the next day) and on weekend (when they don’t), and they wake up later on weekdays (but not on weekend, for which the positive effect of childhood intelligence on adult nocturnality is not statistically significant).
For example, those with childhood IQ of less than 75 ("very dull") go to bed around 23:41 on weeknight in early adulthood, whereas those with childhood IQ of over 125 ("very bright") go to bed around 00:29.
Looking at that Sunday morning sleep-in time, I'm still trying to figure out if this article is a joke. :-)
Access to endless amounts of cheap energy made us rich, and wrecked our climate, and it also made us the first people on earth who had no practical need of our neighbors.
Our economy, unlike any that came before it, is designed to work without the input of your neighbors. Borne on cheap oil, our food arrives as if by magic from a great distance (typically, two thousand miles). If you have a credit card and an Internet connection, you can order most of what you need and have it left anonymously at your door. We've evolved a neighborless lifestyle; on average an American eats half as many meals with family and friends as she did fifty years ago. On average, we have half as many close friends.
There are psychological implications of our hyperindividualism. In short, we're less happy than we used to be, and no wonder — we are, after all, highly evolved social animals... And so it heartens me that around the world people are starting to purposefully rebuild communities as functioning economic entities, in the hope that they'll be able to buffer some of the effects of peak oil and climate change.
The implication is that we don't really have a direct experience of what we're feeling ‘right now,' but only a memory - an unreliable memory - of what we thought it felt like some seconds or milliseconds ago. The vivid present tense we all think we inhabit might itself be a retroactive illusion.
“Any time you have to estimate a numerical value, it turns out you’re very susceptible to the power of suggestion,” says William Poundstone, author of the new book Priceless: The Myth of Fair Value (and How to Take Advantage of It). “Any related value that you hear just before you make your estimate really does have this big statistical impact on what number you’re going to estimate.”
In other words, at the moment Jobs says, “The pundits think we’re going to price it at under $1000,” this plants a seed in your mind: an iPad costs something like $1000. When he reveals the real price, you feel like you’ve just saved $500. If he said, “We were thinking of pricing it at $399, but we decided to go for $499,” that would feel like a ripoff—even though absolutely nothing has changed.