How do we filter visual information?

Department: Experimental & Applied Psychology
Section: Cognitive Psychology
Research area/-theme: perception, cognition, memory, brain functions
Researcher: Chris Olivers
Grant: ERC Consolidator 

When we open our eyes, a near-180° widescreen television programme of visual information floods into our brain. Attention processes actively and dynamically filter this information based on what is relevant or irrelevant to us at that particular moment. For example, searching for a road sign in an unfamiliar city or looking for bananas in the fruit and veg section of the supermarket. The current standard model states that these filters are applied using the working memory – a dynamic system in which information is stored for a short time and manipulated. Our perception is automatically influenced by what is active in our working memory at that particular moment.

With the aid of a prestigious ERC Consolidator Grant, Professor Chris Olivers is studying this interaction between memory and perception. Things are not as simple as was originally thought and there is still much we do not know. Firstly, it seems that at any given moment, the brain can check which active memory tracks are and are not influencing perception. How does this happen? Secondly, the brain's capacity to filter the information seems to be seriously limited – much more so than people had expected based on the capacity of the working memory. What causes this? And thirdly, the perception often seems to be influenced much more by other memory systems than the working memory, such as the implicit (unconscious) memory and the long-term memory. For these systems, habits are frequently more decisive than the optimum choice at that point in time. How does the transition between various types of memory take place and how does the system retain the necessary flexibility?

Using the latest techniques, measurement of perception, eye movements and brain activity is conducted to determine how and when the memory influences the sensory input, what type of memory is used to do this, which brain functions determine this, and what dynamics are created by switching between various filters. Amongst other applications, the results are expected to offer important new insights into theories about perception as well as leading to new guidelines for practical applications.