Pascal Haazebroek

Research Interests

In my PHD research I focus on the computational modeling of interaction between perception and action both in humans and robots. Traditionally, humans are thought to first perceive the world, then reason about it, and finally choose and execute an action to achieve their goals. These logical steps often form the basis of cognitive architectures that control robots. However, numerous empirical findings from experimental psychology suggest that this serial view is to simplistic: perception and action in humans not only occur simultaneously, they influence each other as well.

In my studies I aim at gaining a deeper understanding of this interaction by creating computer models that approximate human behavior in a variety of experimental conditions.

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Research Projects

HiTEC
During my PHD project I am developing HiTEC, a cognitive model that is able to replicate typical experimental psychological phenomena such as stimulus-response compatibility, feature binding, active perception and decision making.

In my studies I use dynamic models of the environment and the agent. The agent is controlled by the HiTEC cognitive model which is constructed using PDP/Connectionist-like network methods. The focus in my simulations is on replicating empirical findings on the cognitive coding of perceptual and action-related features and their mutual interaction.

The (ultimate) practical goal for the cognitive model is to endow cognitive robots with means to control their action and perception in dynamic environments. Additionally, the model can be used in Human Computer Interaction as a human performance model for perceptual and action related tasks in real world and virtual environments.

PACOPLUS
My research is part of a larger EU funded project, PACO-PLUS. PACO-PLUS aims at the design of a cognitive robot that is able to develop perceptual, behavioral and cognitive categories in a self-emergent and measurable way and communicate and share these with humans and other artificial agents. The main paradigm of PACO-PLUS is that Objects and Actions are inseparably intertwined and that categories are therefore determined (and also limited) by the action an agent can perform and by the attributes of the world it can perceive.

Visual Pop Out
For my Psychology Master's Thesis I implemented a computational model of visual attention. In this model, the phenomenon of visual pop-out is replicated by explicitly modeling the ventral and dorsal processing pathways of the brain. At different levels, competition between elements in the visual scene drives the overall dynamics towards convergence. Different visual scenes (e.g., a varying number of distractors) show different courses of activation and response times similar to those found in empirical studies with humans. This suggests that the brain may - functionally - employ such a mechanism of attention.

HCI Claim Explorer
In this project I developed a web application that facilitates the process of usability evaluation. Usability experts typically analyze software and websites on aspects and features that may vary over projects but also show a lot of overlap. This tool lists typical issues for the analyst to check and relates each issue to aspects from cognitive psychology offering the analyst a theoretical basis (at the fingertips) for numerous usability problems. The list of possible issues are the result of an in-depth analysis of a large body of archival reports from a consultancy company (2C / Metrixlab).

Web Event Based Usability Evaluation
For my Computer Science Master's Thesis I designed and implemented a novel way to unobtrusively measure online user behavior. By adding a single line of javascript code to any website, I am able to intensively log the online behavior of any user of that website including mouse cursor movement, mouse button activity, keyboard activity et cetera. By sending this data (encrypted) to a database I can replay individual user visits, plot overall behavior on the individual web pages (e.g., heat maps) and by using data mining techniques compute regularities that may help improving the website's usability.

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Publications

I contributed to the following scientific publications:

	Haazebroek, P., van Dantzig, S., & Hommel, B. (2009). Towards a computational account of context mediated affective stimulus-response translation. Proceedings of the 31st Annual Conference of the Cognitive Science Society. Austin, TX: Cognitive Science Society
	Haazebroek, P., & Hommel, B. (2009). Anticipative control of voluntary action: Towards a computational model. In Pezzulo, G, Butz, M.V., Sigaud, O., & Baldassarre, G. Anticipatory Behavior in Adaptive Learning Systems: From Psychological Theories to Artificial Cognitive Systems, Lecture Notes in Artifical Intelligence, 5499, 31-47.
	Haazebroek, P., & Hommel, B. (2009). Towards a Computational Model of Perception and Action in Human Computer Interaction. In V. Duffy, Digital Human Modeling, Lecture Notes in Computer Science (Vol. 5620, pp. 247-256). Springer Berlin / Heidelberg.
	Joost Broekens and Pascal Haazebroek (2007). Emotion and reinforcement: Affective facial expressions facilitate robot learning. In Proceedings of the IJCAI Workshop on AI for Human Computing (AI4HC'07, Hyderabad, India) (pp.47-54).
	Lacroix, J. P. W., Postma, E., Hommel, B. & Haazebroek, P. (2006). NIM as a brain for a humanoid robot. In Proceedings of the Toward Cognitive Humanoid Robots workshop at the IEEE-RAS International Conference on Humanoid Robots 2006. Genoa, Italy.
	Marc de Kamps, Frank van der Velde, Gwendid van der Voort van der Kleij, Pascal Haazebroek (2006). A model of global saliency: Selecting a target object among distractors. CNS 2006. Edinburgh, Scotland

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Presentations

I gave the following science related presentations:

	Cognitive Robotics. Labyrint Alumni lezing Leiden (February, 2010)
	The psychology of an Object Action Complex. Humanoids Conference Paris (December, 2009)
	Towards a Computational Account of Context Mediated Affective Stimulus-Response Translation. Cognitive Science Conference, Amsterdam (August, 2009)
	Towards a Computational Model of Perception and Action in Human Computer Interaction. Human Computer Interaction International Conference, San Diego (July, 2009)
	Kunnen robots denken? Brain Awareness Week, Science Café Leiden (March, 2008)
	AIO Cognitieve Psychologie. Psycholoog en Toekomst Perspectief Congres Leiden (November, 2007)
	Mastercursus Human Computer Interaction for Psychology Students. Education track, CHI Conference Eindhoven (May, 2007)

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Teaching

Master's Course: Human Computer Interaction
New technologies provide the means to build wonderful tools to extend our cognitive system into the world, as well as producing the most annoying systems in terms of performance, ergonomic design, and aesthetics.

This course provides an overview of recent approaches towards a scientific as well as a practical understanding of basic issues of usability, representation and coordination that arise in interface design and related areas. The cognitive issues that are involved in designing interactive systems are discussed and the typical real-world life cycle of the development of a software product is presented.

The course features guest speakers sharing their practical expertise, and field trips to state of the art usability labs. In practical assignments students evaluate the usability of actual software products.
View Blackboard module

Bachelor's Course: Cognitive Ergonomics
This course focuses on applying cognitive psychology to real world situations. Problems in decision making, design, law and automation are discussed. My lectures are on the design and automation of software, machines, cars and airplanes, providing a basic treatment of the issues and research methods involved in this domain.
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Supervised student projects

	Randy Lek: Wiimote as input device in behavioral experiments (Master's Thesis)		Annamarie Piederiet: Usability study on Van Dale dictionary (Internship)
	Paul de Haas: Study of online banner advertisement effectiveness (Internship and Master's Thesis)		Franklin Widjaja: Study of online search behavior (Internship)
	Frank Versteegh: Visual clutter in cockpit displays (Internship)		Pieter van Leeuwen: Usability study on medical administration software (Internship)
	Allard Sierksma: Usability analysis and implementation assessment of patient administration software (Internship)		Bonnie van Huik: Study at Consument en Veiligheid on prevention of injuries at sport (Internship)
	Arjan Bruin: Usability analysis of timeline-based research tool for accident analysis		Kim Walma: Usability analysis of websites and software
	Laurens Kalf: Usability analysis of Simgroep's Gemeente Websites (Citizen Self Service)		Judith Van Dam: Analysis of EXACT's software focusing on real world HRM processes
	Dorien Zevenbergen: User Experience Research Department		Aletha Duijveman : Usability analysis of the new Van Dale dictionary software
	Marleen Spiekman : Virtual assistants and social robots to support senior adults in their homes

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Curriculum Vitae

Working experience

2006 - Present	PHD position Course Instructor	Leiden University Cognitive Psychology
2000 - 2004	Teaching assistant	Leiden University Leiden Institute of Advanced Computer Science (LIACS)
1998 - 2004	ICT specialist	Fortis Bank

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Education

1999 - 2005	Doctoraal (BSc + MSc equivalent) Cognitive Psychology	Leiden University
1998 - 2004	Doctoraal (BSc + MSc equivalent) Computer Science	Leiden University Leiden Institute of Advanced Computer Science (LIACS)

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Committees

2008 - Present	Board member	Cognitive Psychology Unit Leiden University
2001 - 2002	President of the board	Labyrint Student Association Psychology, Leiden University

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Personal Interests

Photography
Every now and then I take my Canon 40D out on a trip. My 'portfolio' is still rather limited, but every photo shoot is another opportunity to learn more. I especially like the way a limited depth of focus can guide the viewer's attention to the interesting parts of a scene, or how a little blur can add to the general feeling of a picture. In addition, I am in constant doubt whether I should buy another camera lens (macro or zoom lenses seem like fun). For now, I just keep on fiddling with what I have.

Video editing
For me, another creative outlet is video recording and editing. People in subtle, yet challenging social situations, their natural habitat or something obviously made up, can be such interesting 'objects of registration'. In the past I did some video work for fun with George van Hal. Now we also work on more serious projects and try to refine our skills both with the camera and in editing.

Volleyball
Weekly training, matches and the occasional tournament are all part of my Volleyball career. I always have a lot of fun with my teammates and joining a sports club really has prove to be a valuable addition to my leisure activities. It's nice to have a 'playful' purpose for maintaining my general fitness and no other activity in my social life includes or allows the amount of shouting and yelling and expressions of passion, anger and praise as an intensive volleyball match.

Running
Every now and then I need to realign my thoughts. I put on my running shoes and hit the road. When I match my pace to the beat of the music, I can surrender to the rhythm and let my mind wander, exploring new trains of thought. Once in a while I decide to challenge myself and sign up for a running contest (e.g., Dam tot Damloop). It is intriguing to learn where your real limits are during such a personal encounter between the 'actual challenge from the outside' and the 'will to achieve on the inside'.

Travel
Science is international. So to collaborate or merely to present my work to colleagues, I often need to travel. My project is European, so I have visited plenty of universities in our continent. But sometimes a conference in the USA or even in India may be of great value. Whenever possible, I try to combine work and leisure and get around the city or country I am visiting.

On Stage
When not teaching a class, I sometimes still like to be on stage trying to move the audience. Nothing quite compares to that very situation where every word, every pause and every subtle movement or gesture is being attended to by a crowd. There is immense pressure originating from the expectations from the audience and the uncertainty of meeting their criteria. At that exact same time there is this sense of power, as if I'm holding a handful of strings and each string manipulates the thoughts and feelings of the spectators. I never feel well prepared, yet that's precisely why being on stage can be fulfilling. I hate it and I love it.

Software development
Apart from working on scientific projects, I like to maintain my coding skills as a trained computer scientist and work on fun projects as well. I really like the Microsoft .NET framework for the extensive code libraries and coding communities that can help realizing a novel idea in fractions of the time it would take using alternative frameworks or platforms. In my web design projects I am currently trying to harness the power of Code Igniter.

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