ProfessorFrans Verstraten

Project Opportunities

Title: Recalibration mechanisms in vision: Adapting to a changing environment

Summary of opportunity:

To survive successfully humans must accurately with the environment. However, the environmental conditions can change, sometimes drastically in a very short time. An organism is very good at recalibrating to new environmental condition. However, the underlying mechanisms are still not well understood.

Opportunity synopsis:

We are interested in how the brain and in particular the visual system adjusts itself to a constantly changing environment. For example, when you start driving 50 km/hour feels pretty fast. However, after an hour or so on the highway and going back to a 50 km zone, it feels like you driving much slower. This is a form of recalibration to new environmental conditions. We are especially interested in the temporal aspects. Some recalibrations take only seconds, other days.

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Project Opportunities

Title: The visual brain as an interpreter; What, Where and When.

Summary of opportunity:

The brain is an interpreter. Visual information that arrives in the brain from our retina is initially mostly stimulus driven. That is, the initial processes along the pathway of visual information processing are close to automatic. However, at certain levels the processing can be affected by several factors. These factors (among others) can be prior knowledge, adaptation, instruction and attention. We are interested in which parts of the visual information processing structures are affected by these factors.

Opportunity synopsis:

Once in a while you have that "Aha" experience. Parts of the visual scene do not make sense until the information suddenly organizes itself into something you understand or can interpret. Although there is no change in the available stimulus information, the brain changes its activity at that time (or even earlier). Initially the brain was concerned with processing the incoming visual information. Later it works on the representation. These sudden changes are an excellent tool to study how the brain makes sense of the world.

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Project Opportunities

Title: Applied vision science: towards a better understanding of what the brain knows.

Summary of opportunity:

Many processes in the brain are not consciously accessible. This makes it hard to find out how for example subjects reach decisions. There are several ways to find out what the brain ‘knows’ that cannot be verbalized by the observer.

Opportunity synopsis:

Vision scientists know a lot about the early stages of visual information processing. We know how visual acuity, colour, contrast, motion etc. We also know lots about how attention works. So basically, we can make sure that presented information can be perceived (think about information in traffic, advertising, marketing communication, awareness campaigns, wayfinding etc. However, that does not mean that observers actually use this the information. For example, whether the attitude of people change after being confronted with new information. We are interested in developing techniques to measure what is actually picked up by the observer and whether it has an effect on behaviour. We used sophisticated eye-movement recording, physiological indicators as well as behavioural tasks.

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Project Opportunities

Title: Homo Integralis 1: Motion perception for moving observers

Summary of opportunity:

The perception of motion and movement has been studied for a long time, often under very controlled conditions, in dark rooms, with the head stabilised. However, human perception mostly occurs under conditions that are far above perceptual threshold and in particular under conditions observers are not stationary. Our goal of this project is to look at motion sensitivity under conditions where observers are moving, or being moved, using a state of the art 7 degrees-of-freedom motion simulator (see also Hogendoorn, Alais et al, Vis Res 2017) and use head-mounted displays to present motion stimuli.

Opportunity synopsis:

The perception of motion and movement has been studied for a long time, often under very controlled conditions, in dark rooms, with the head stabilised. This has given science a clear insight into how sensitive the human motion system is, typically represented by easy to reproduce sensitivity and tuning curves (See work by Fredericksen, Verstraten & Van de Grind, mostly in Vision Research in the mid ‘90s). However, human perception mostly occurs under conditions that are far above perceptual threshold and in particular under conditions observers are not stationary. That means that other senses are active, in particular the vestibular system, and our goal of this project is to look at motion sensitivity under conditions where observers are moving, or being moved. For this we use a state of the art 7 degrees-of-freedom motion simulator (see also Hogendoorn, Alais et al, Vis Res 2017) and use head-mounted displays to present motion stimuli.

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Project Opportunities

Title: Homo Integralis 2: Transparent motion and the moving observer

Summary of opportunity:

Transparent motion or motion transparency is still a rather badly understood phenomenon. One can create spatial motion transparency and temporal motion transparency. The second part of the project is the detection of motion under transparent conditions, where we manipulate the motion directions of both the stimulus as well as the observer, using a state of the art 7 DOF motion simulator and head-mounted display.

Opportunity synopsis:

Transparent motion or motion transparency is still a rather badly understood phenomenon. Classic models of motion detection have problems explaining motion transparency (See Snowden & Verstraten, TICS, 1999). There are still some interesting phenomena that occur under transparent motion conditions that remain to be investigated. First, consider the way one can generate motion transparency (see Van Doorn & Koenderink, 1982a, and 1982b, Experimental Brain Research). In short, one can create spatial motion transparency and temporal motion transparency. The second part of the project is the detection of motion under transparent conditions, where we manipulate the motion directions of both the stimulus as well as the observer. For this we use a state of the art 7 DOF motion simulator and head-mounted display.

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Project Opportunities

Title: Homo Integralis 3: Adaptation to (transparent) motion and a moving observer

Summary of opportunity:

Motion perception is inherently related to adaptation, and multiple sites of motion adaptation exist along the pathway(s) of visual motion processing. Motion transparency under conditions of a moving observer opens up new possibilities to investigate the contributions of different gain controls in different sensory systems in our brain. For this we use a state of the art 7 DOF motion simulator and head-mounted display.

Opportunity synopsis:

Motion perception is inherently related to adaptation. One kind of motion adaptation shows itself as the motion aftereffect (see Anstis, Verstraten, & Mather, TICS, 1998). If one thing has become clear in recent decades, it is that multiple sites of motion adaptation exist along the pathway(s) of visual motion processing. Motion transparency under conditions of a moving observer opens up new possibilities to investigate the contributions of different gain controls in different sensory systems in our brain. For this we use a state of the art 7 DOF motion simulator and head-mounted display.

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Project Opportunities

Title: Homo Integralis 4: Orienting attention for moving observers

Summary of opportunity:

The goal of this project is to understand the role of vestibular input in the orienting of attention. Again, we look at the role of attention under conditions where observers are moving (active), or being moved (passive), using a state of the art 7 DOF motion simulator and head-mounted display.

Opportunity synopsis:

William James wrote “everybody knows what attention is”. However, given the number of papers that were published after he wrote that statement shows that there was more to the story. The goal of this project is to understand the role of vestibular input in the orienting of attention. Again, we look at the role of attention under conditions where observers are moving (active), or being moved (passive), using a state of the art 7 DOF motion simulator and head-mounted display.

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Project Opportunities

Title: Psychophysical and high-tech approaches in the diagnosis of mental health and psychological disorders

Summary of opportunity:

We focus on the possible role of psychophysical techniques in diagnosis of mental health and Psychological problems. We use advanced Virtual Reality techniques and (neuro)biological markers (such as eye movement, pupil size, heart rate variability, galvanic skin response) to gain insight into how the brain reacts to psychological factors and how to come up with fast and reliable diagnostic tools with an eye for therapeutic outcomes as well.

Opportunity synopsis:

Psychophysical methods are beautiful ways to reveal how the brain processes sensory information. Traditionally perceptual scientists were less concerned with the applications of their findings. However, in particular during the Covid-19 period but also before, it has become clear that remote access to mental health support is poor. New techniques, in particular in the audio-visual domain, make it easier to communicate but a lot of work remains to be done. We focus on the possible role of psychophysical techniques in diagnosis of mental health and Psychological problems. We use advanced Virtual Reality techniques and (neuro)biological markers (such as eye movement, pupil size, heart rate variability, galvanic skin response) to gain insight into how the brain reacts to psychological factors and how to come up with fast and reliable diagnostic tools with an eye for therapeutic outcomes as well.