The brain cares deeply about novelty. Electrophysiological responses to novelty can already be found in neonates, and soon in life a rudimentary orienting response appears, the more or less automatic reflex of humans and nonhuman animals to investigative new objects or situations. Novelty also has a strong, but little understood, impact on learning. Such responses of the brain to novelty are studied extensively in psychology and neuroscience. Moreover, novelty responses are increasingly used as markers of cognition in animal research and in research on infants.
Although novelty is thus fundamental in psychology and neuroscience, surprisingly little is known about how the brain detects and responds to novelty. In a large project, my coworkers and I try to answer fundamental, unsolved questions about novelty: Where in the brain is novelty detected? How is it detected? What consequences does its detection have in the brain and on behaviour? Techniques we are using to answer these questions include electrophysiology, rodent studies, psychopharmacology, behavioural methods and computational modelling.
So far, we have discovered that responses to novelty can be
grouped into two classes. One class contains responses to never
having seen a stimulus (i.e., to real novelty). Novel stimuli
activate more neurons in the brain than familiar stimuli, they
draw attention to themselves, and they give a boost to learning.
The second class consists of responses not to novelty, but to
unexpectedness. Novel stimuli elicit these responses only when
observers expect some simple, known stimulus and are instead
confronted with a complex, novel one (or nonnovel; familiar
complex stimuli also elicit this second class of responses).
Stimuli that are unexpected in this way also draw attention to
themselves, and arouse us.
The programme is still continuing, looking in more detail into learning benefits from novelty, how novelty guides exploration of the world, and what brain areas are truly essential for the process of detecting novelty. The programme may result in adjustments of the role of novelty and surprise in education (are its effects really only positive?), and could help research on clinical diseases in which novelty processing is thought to be deviant (e.g., schizophrenia).