Photo of two birds overlaid with a typical set of eye movements
Our perception is of a seamless visual world, but in reality a sharp image is available only at the very centre of gaze. Accurately planned eye movements are vital to explore our visual environment.

Why do we make errors in understanding what we see and in remembering what we've seen? Uncertainty and variability are fundamental aspects of human behaviour, which worsen with advancing age or neurological disease. In the lab we measure these factors using visual psychophysics and memory tasks, eye tracking and limb motion-tracking. Then, using mathematical models and computer simulations, we develop and test hypotheses about the underlying brain mechanisms.

One focus of the lab is on visual memory. Our ability to recall what we have seen is surprisingly limited: rather than a fixed capacity on how many objects we can remember, our work shows that the limit is on the resolution with which visual information can be maintained. Visual memory acts like a resource that can be allocated to important information in our environment: we investigate how this resource is distributed between features of the visual scene and how it is updated when we move our eyes.

Plots of movement paths showing increasing scatter from left to right
Reaching movements to a remembered target. Increasing the number of locations held in memory at one time (from left to right; other targets not shown) results in increasing variability in recall.
In everyday life, we shift our gaze several times per second in order to extract detailed information from the world around us. These movements represent a simple case of exploration and decision-making behaviour. A second focus of our research is to understand the processes that decide where, when and in what order eye movements are directed.
University of Cambridge

In the brain, information about our environment and our planned actions is reflected in the spiking activity of populations of neurons. Recent work in the lab involves developing computational models of encoding and decoding of neural activity that explain aspects of human perception and behaviour.