Stimulation from the environment is vast, ambiguous, and noisy – only a fraction of the information that reaches our sense organs is perceived, stored in memory, or acted on. We are oblivious to most of what excites our sensory systems from the world around us, and within our own bodies. Yet, humans still manage to extract useful information from their surroundings with impressive efficiency. Somehow, we are able to engage our cognitive resources on topics that are relevant and important, while ignoring everything else. How is such a feat accomplished?
One idea is that prior knowledge helps us to prioritize between different sources of information. Our species have through evolutionary time adapted to the structure of our environment, now expressed in the architecture and sensitivities of our brains. This form of prior knowledge is built into our genes, and is presumably stable across time and similar between us. In addition, we also acquire knowledge as individuals through our own experiences.
We learn for example that some events tend to co-occur in space or time, or that some actions tend to be followed by events that we like or dislike. Thus, what we see or experience in a particular situation, depends not only on what currently stimulates our senses, but also on what is stored in our nervous system. In this sense, our experience of the present is in part “premembered”. Such knowledge can be a powerful guide when navigating information space.
Another idea is that we constantly make active decisions on which information to select from the huge range of objects and features available to our senses. For example, we may judge some information to be predictive of a reward or desirable outcome of some sort, or that it will reduce our uncertainty about important factors in our environment. Some information might also simply feel good to think about, or feel good to avoid thinking about. Such consideration may guide our decisions on what to prioritize and what to ignore. Thus, what each of us see and experience in a particular situation depends not only on what is actually present, but also on the visual choices we make.
Other factors, such the physical saliency of features or objects, and potentially several more, also influence priority of information processing. Although there are several sources of priority, which have different neural underpinnings and temporal profiles, they can all lead to the same behavioral outcomes, such as improved accuracy, reduced reaction time, and more intense or extended task engagement. However, we do not know if or how the various sources of priority interact to influence these behavioral manifestations.
In the BrainPriority project we will develop experimental designs in which we can manipulate two or more sources of priority concurrently. We will also develop tools for manufacturing tailor-made stimulus materials to elicit particular behavioral or brain responses.