Curiosity is a welcome trait in many respects and is the fuel that powers science. Yet literature is filled with fables that warn of the seductive danger of curiosity (think of how Orpheus loses his wife Eurydice forever after he succumbs to the temptation to glimpse at the underworld). In real life too, we all know the regret that can follow if we give in to curiosity – glancing at a private message that we shouldn’t have, for instance, reading a TV review when we know it contains spoilers, or trying out what happens if you put metal in a microwave (tip: don’t).
From whence does curiosity derive such power over us? One answer lies in the brain. In a pair of brain-imaging studies published as a preprint at bioRxiv – aptly titled Hunger For Knowledge: How The Irresistible Lure of Curiosity Is Generated In the Brain – Johnny King Lau and his colleagues have shown that curiosity appears to be driven by the same neurobiological process as physical hunger.
The researchers laid the groundwork for their brain-scan research with a small behavioural experiment in which hungry volunteers were shown either magic tricks or pictures of tempting food, and then presented with a lottery wheel.
This wheel provided a visual presentation of the odds of a gamble (which varied from trial to trial) – if they won, they would have an increased chance at the end of the experiment to learn how the trick was done or to eat the food; if they lost, it was more likely they would suffer a mild but unpleasant electric shock at the end of the experiment. Each trial the volunteers rated their curiosity about the trick or the desirability of the food, and then chose whether to take the gamble or not.
The main finding here was that curiosity and hunger both swayed the volunteers’ decision-making. Above and beyond the actual odds on any trial, the volunteers were more likely to take gambles when they were more curious about the magic or more tempted by the food, even at the risk of suffering an electric shock.
This led Lau and his colleagues to hypothesise that curiosity fuels a physiological wanting or craving, similar to hunger. To test this, they repeated the set-up with more volunteers and this time scanned their brains too. The results showed that, whether influenced by hunger or curiosity, when their participants opted to take the gamble, activity was greater in a key region of the brain known as the striatum, which is known to be associated with motivation and reward.
Moreover, when driven to make the gamble, the participants showed a greater disconnect between the striatum and the sensorimotor cortex, indicative perhaps of a discounting of the physical risks of their decision (I would add a caveat: it is always difficult to interpret the functional meaning of brain activity, especially in exploratory work of this kind, so this interpretation should probably be considered tentative).