Dr Casimir Ludwig

"As you do more research, it’s clichéd but it’s true; you find more questions than you answer. There’s always a new direction to explore, a new perspective to take."

Dr Casimir Ludwig started off studying psychology at the Radboud University Nijmegen before going on to specialise in neuropsychology.

It was his experience of working on visual attentional control in neurological patients at the MRC-Cognition and Brain Sciences Unit, alongside Professor John Duncan FRS, that inspired him to pursue a career in academic research.

Casimir obtained his PhD from Bristol University in 2003 and has been awarded several successive research grants ever since to continue his work on how visual information is used in the control of behaviour and decision-making.

Most people are not aware of the limitations of their visual and cognitive processing machinery. So when you tell them that you can’t see everything that’s in front of you and that you’re really quite limited in what you can see, that’s often a big surprise.

Then it’s easy for them to understand why understanding how we overcome that limitation is worthwhile and could potentially have implications that go beyond academia – such as when you are walking along, or driving, the way you take up information is obviously quite important.

There are limitations in our visual system and our cognitive processing capacity, which means that we have to sample our environment discreetly by shifting our gaze and taking information from different parts of our world.

My research focuses on understanding the decision processes that lead to these gaze shifts – so every time you fixate on a region and take some information from it, it may not feel like a decision but it’s still a decision about when you move on and how long you stay based on that visual information.

One particular issue in that domain is that the temporal aspects have always been disassociated from the spatial aspects – the decision of where to sample the environment has been decoupled from the decision of how long to stay in one place before moving on to sample the next point.

One of my objectives is to provide an overall integrated theoretical framework that joins these two components.

I don’t think there was ever a grand plan that I would go into psychology. As with many jobs, once you’re in you get very excited and enthusiastic, particularly with a PhD where you have the freedom and time to look into a particular subject.

I thought that what I did was exciting from the start. My field requires input from various different disciplines, such as computer science neurosciences and cognitive science, and that kind of mixture immediately made it really exciting and challenging at the time – and it still is.

There’s always a new direction to explore, a new perspective to take. As you do more research, it’s clichéd but it’s true; you find more questions than you answer. It’s still a very fruitful area of research.

Interacting with other disciplines is vital because it’s an area where the low hanging fruit have been picked and to really make progress you do really need to interact with different disciplines.

Bristol Vision Institute includes various different schools and faculties, people who are interested in any aspect of vision whether that’s biological, human or machine.

For me the big question is how vision is used to guide extended forms of behaviour. For example, a lot of research into how vision is used to guide action basically involves studying a temporal snapshot of that behaviour – so I might study how I use vision to guide a reaching moment to reach my cup of coffee.

But most of our behaviours are much more extended than this, if you think about actually making the cup of coffee to reach out to. It’s not just the case of these extended actions being treated as a sequence of individual actions, action sequences often unfold according to what may be seen as a well-established, hierarchical “schema” which we sample information from the environment which then influences our behaviour.

But that’s a real challenge because you’re looking at behaviour over longer timescales, you’re looking at coordinated behaviour so it’s not just making a single grasping movement, rather the coordination of different motor systems – the eyes, the head, the feet, the hands.

The broader challenge is to study how vision contributes to more naturalistic everyday behaviour. Most of my work to date has been about the basic operating characteristics of the basic motor systems – it’s a bit like characterising what a biological system is capable of in principle.

That’s very useful and you can make links with the neuroscience but you also have to use very restricted experimental protocols to how visual information is coded and used to drive a particular motor system. The next challenge is to go beyond that and look at the role of vision in more naturalistic environments.

That’s what the Bristol Vision Institute Movement Laboratory is about – it gives us the facility to embed human subjects in a visual world and yet have tight control over that world so we can measure what they do, from the movements of limbs, head and eyes.

There’s a real tension there for me because I like doing well controlled experiments, collecting clean data and developing models to account for that data. But when you start looking at more complex forms of behaviour you have less control over the data and things become difficult in a way that is just different.

Characterising the basic operating characteristics of a system doesn’t necessarily mean that that system behaves in the same way when you take it out into the real world. But it gives you some insight into what it’s capable of and what signals it has access to and that helps us understand the brain without necessarily measuring or probing brain activity directly.

Using sophisticated behavioural methods and measures, we hope to identify the computations that transform sensory inputs into motor outputs. In this way, we provide hypotheses about the kinds of signals used by the brain in producing coherent and adaptive behaviour.”

Dr Casimir Ludwig, Reader, School of Experimental Psychology

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Watch Casimir discuss what it means to be a scientist in the 21st century in our new film Facing failure: what it takes to be good at science.

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