As we explore the visual world, we move our eyes 2-3 times per second. A direct consequence of such motor behaviour is that the image on our retina is continuously being altered by our self-generated motions. Yet, we perceive an invariant and stable world. More intriguingly, we effortlessly detect real image motions in the world that are not caused by ourselves. That is, because our environment is not just a static “picture” in front of our eyes, visual images of the world can be highly dynamic, with the potential for sudden or gradual changes in light contrasts, or for the entrance of completely new objects into our visual field. We thrive on such dynamism even when we clutter it further with our own eye movements.
How do we do this? How do we deal with dynamic visual information and differentiate between motion happening in the environment versus motion just created by us moving our own eyes? How do we select what is relevant and what is not, and how do we program the correct type of eye movement response to look at what’s relevant, be it by generating a fast ballistic movement to redirect the fovea on a new part of the scene or by employing a smooth rotation of our eyeball to track a moving object.
These are just a few of the main questions that I am interested in, and I tackle them all through careful experimental approaches aimed at isolating, to the best of our abilities, individual aspects – whether sensory, motor, or cognitive – of these questions and uncovering their underlying mechanisms. I use well crafted visual environments, and I pair them with state of the art real-time recordings of eye movements (e.g. video based eye trackers and scleral search coils).
For many of my experiments, I investigate the mechanisms behind well known behavioural phenomena, both in isolation and also how they may be linked to each other. For example, in one phenomenon, “saccadic inhibition”, an abrupt visual flash inhibits an impending movement, and in another, “peri-saccadic mislocalization”, the percept of the location of an abrupt visual flash is altered if the flash occurs near an impending saccade. Intriguingly, both phenomena involve highly similar visual stimuli and eye movements but exercise different aspects of brain processing, and my goal is to understand these aspects and how they are linked.
More broadly, I use my findings from individual experiments to make inferences on how the visual system might operate in more ecological situations than in a laboratory setting. My long term goal is to employ more complex scenarios with naturalistic pictures or short movies, together with models of the oculomotor system, to gain a better understanding of not only eye movement control, but also of how a comprehensive visual percept is built to allow humans to so effortlessly interact with their environment.