When we actively pursue new information through our curiosity, we’re rewarded with a flood of the pleasure-inducing chemical dopamine.
In addition to the reward system, other areas of the brain play a role in curiosity as well. It appears that regions dedicated to working memory in the prefrontal cortex allow us to distinguish between new and previously experienced stimuli. After all, how could we have anything but curiosity if we couldn’t recognize things we’ve already encountered? It looks like the center most responsible for our sense of curiosity is the dentate gyrus, a part of the brain’s hippocampus.
In 2009, researchers discovered that increasing the expression of a protein that interacts with dopamine in the dentate gyrus significantly increased curious behavior in animals [source: PhysOrg]. Again, dopamine appears to play a significant role in curiosity.
Exactly how that role is carried out, and what other aspects of curiosity remains uncovered are still a mystery. Because curiosity is considered the driving force behind scientific curiosity, it’s a pretty sure bet that it will eventually lead researchers to a full understanding of itself.
In 2007, a team of researchers at the Max Planck Institute discovered what they termed a “curiosity gene” in the great tit songbird. This gene, the Drd4 gene, is responsible for creating receptors for the neurotransmitter dopamine. Birds displaying a common variation on the gene showed a greater propensity to visit new areas and explore unfamiliar objects placed in their cages [source: Max Planck Institute].
Animals have long been known to display their own types of curiosity, like rats exploring new areas of a maze without any expectation of food or reward and primates that learn to open windows on cages to get a peek at what’s going on outside in the research lab. While this behavior may not fit the definition of human trait curiosity, the fact that the “curiosity gene” found in great tit birds related to dopamine is significant.
“Personality-Gene” Makes Songbirds Curious
Max-Planck scientists find evidence for an association between gene variants and exploratory behaviour in great tits
MAY 02, 2007
Whether you are an anxious type, or a fearless person – such individual differences in personality could be partly due to the genes you carry. In humans, it is hard to prove the existence of such “personality genes” – there are simply too many factors that influence human behaviour and these factors are hard to control experimentally. Birds are an easier target for research and indeed, they also have different personalities. An international team of researchers have now found evidence for the existence of a “curiosity-gene” in a songbird, the great tit (Parus major). The gene (Drd4) carries the building instructions for a receptor in the brain, which forms the docking station for the neurotransmitter dopamine. Birds with a specific variant of this dopamine receptor D4 gene show a stronger exploratory behaviour than individuals with other variants (Proceedings of the Royal Society London B, 2 May 2007).
Young great tits exploring the artificial trees in the experimental room.
© Kees van Oers
There is already evidence that variations (polymorphisms) in neurotransmitter-related genes are associated with personality differences among humans. Research from the last decade suggested a promising link between the Drd4-gene and the trait curiosity (novelty-seeking). Scientists from the Max Planck Institute for Ornithology in Seewiesen, together with a former lab member who is now at the Cawthron Institute in Nelson (New Zealand) and with colleagues from the Netherlands Institute of Ecology in Heteren, have shown that the choice of the Drd4-gene in the study of the great tit turned out to be a good bet.
In the Drd4 gene of this bird, they discovered 73 polymorphisms, of which 66 were so-called Single Nucleotide Polymorphisms (SNPs), where only a single nucleotide has been exchanged between the two variants. One such SNP, located at position 830, is indeed associated with the exploratory behaviour (read: curiosity) of the birds. This is first shown in two breeding lines of great tits, which the researchers had selected over four generations according to their level of curiosity (a low and a high curiosity line). The scientists assessed the curiosity of the birds in a test which shows similarities to the traditional “open-field” test used by psychologists. They tested the exploratory behaviour of each bird soon after it left the nest (Early Exploratory Behaviour, EEB), as follows. In one behavioural test, the biologists measured the time until a bird had visited four artificial “trees” after being released in the observation room. In a second test, they quantified the reaction of the bird towards each of two unknown objects that had been put in its cage. One such novel object was a pink panther. In the human brain, our curiosity is treated much like other pleasurable activities like eating.