Research topics

Attention and consciousness

I am also currently engaged in various projects that aim to elucidate the specific interaction between attention and consciousness. Is attention always necessary for conscious perception? Are there possible opposite effects of attention and consciousness on our perception of subsequent visual scenes? And can we define regimes where attention work in unison and where they work independently?

A lot of questions there, ..., and therefore a very interesting area of study.

This research is done in collaboration with many different researchers, among them are Nao Tsuchiya at Monash University, and Christof Koch, now CSO at the Paul Allen Institute

Biological Motion

Biological motion is heavily studied ever since it was studied by Gunnar Johansson in the early 70s. I am specifically interested in whether there are any differences between different types of actions. Are some action more or less easily carried by point-light movements then others? Are there any differences in how attention and involved in the processing of biological motion, or perhaps in how attention is drawn to different actions?

This research is done in collaboration with Hongjing Lu at UCLA.

For those interested in making their own 3D actions based on motion capture data, I have a page with links to (free) motion capture databases.

Individual differences

In my research on attention/consciousness, and biological motion I am perticulary interested in individual differences and how they relate to personality traits, or performance on unrelated tasks. Sometimes individual difference can reveal information that would otherwise not be visible. An example from my own work is Brascamp, et al. (2010) (see Publications).

Motion perception

Previously I worked on motion perception in humans. More specifically I was (and still am) interested in the question whether or not we have a single or multiple motion systems. Several such systems have been proposed in the literature: slow/fast motion systems, first/second order motion systems, long/short-range motion systems, and attentional/low-level motion systems.

I have taken a closer look to the proposed division in slow/fast motion systems, and evidence that suggests that the reported dichotomy depends on the differential read-out of a single motion system by the use of different stimuli, and not on a real division of the motion system (see Publications).

Binocular rivalry

Binocular rivalry is one of the workhorse techniques in consciousness research. Notwithstanding this imporant function, it is an interesting phenomenon in its own right too! I am particularly interested in the relation of binocular rivalry to other forms of visual rivalry (i.e. monocular rivalry and stimulus rivalry). My focus is on how these difference forms of rivalry depend on the temporal aspects of stimulation. As it turns the different forms of rivalry share an amazing similarity—more than was assumed until now—in their dependence on temporal stimulus parameters (see the Publications page for journal articles).

Visual-motion interactions

Before my graduate studies, I had the pleasure to work with Mark Wexler and Jacques Droulez on the interesting topic of action-perception relationships. Even though we are highly-mobile creatures, vision science is largely focusing on situations with stationary observers, and often is trying hard to prevent artifacts that may be caused by the observer’s actions. Action, of course, should not be considered as a source of artifacts, but as an integral part of the perceptual system (or vice versa). I have worked on the influence of the observer’s actions on his/her ability to estimate depth (see Publications).