Martijn Willemsen Martijn Willemsen researches the cognitive aspects of Human-Technology Interaction, with a strong focus on judgment and decision making in online environments. His applied research focuses on how online decisions can be supported by recommender systems, and includes domains such as movies, health related decisions and energy-saving measures. From a more theoretical perspective, he has a special interest in process tracing technologies to capture and analyze in detail information processing of decision makers.

Invited presentations

  • What recommender systems can learn from decision psychology about preference elicitation and behavioral change
    Talk presented at Boise State University (Idaho) September 9, 2016 and University of Minnesota (grouplens) on September 13, 2016
    slides on slideshare
  • Combining process data and subjective data to better understand online behavior.
    Keynote at the Social Sciences and the Internet conference, July 1, 2016
    slides on slideshare
  • What recommender systems can learn from decision psychology about preference elicitation and diversification Invited talk at Social Psychology Synposium, Tilburg, March 12, 2016
  • Improving user experience in recommender systems: How latent feature diversification can decrease choice difficulty and improve choice satisfaction
    Invited talk at the Applied Software Engineering group, Computer Science Department of Graz University of Technology, Austria, Nov 3, 2015
    slides on slideshare
  • The Why behind Effective Recommenders: User Perception and Experience
    Inivited talk at the 2nd International Workshop on Decision Making and Recommender Systems, 22-23 October 2015
  • Processes of Loss aversion
    Invited talk on in Workshop on ownership and Decision Making in Vienna, September 2013
  • A latent feature diversification algorithm to reduce choice overload in recommender systems
    Invited talk at the Computer Science and Engineering Colloqium Series at University of Minnesota, Minneapolis, MN (USA), November 12, 2012
  • Supporting sustainable decisions by means of a recommendation system for energy-saving measures
    Invited lecture in the 3TU Springschool on Human-Technology Interaction,  Hotel New York, Rotterdam, April 15, 2011
  • Decision Processes
    invited lecture in the 3TU Winterschool on Human-Technology Interaction, Best Western Hotel Ehzerwold in Almen, Jan 28, 2009
  • The who and why of context dependent choice.
    ERIM research seminar, Rotterdam School of Management, Erasmus University, January 19, 2009
  • Testing Cognitive models of context effects using process data
    Research group Marketing, Faculty of Business and Economics - KULeuven, March 2008
  • Process Tracing for Dummies, Solutions for design, analysis and presentation using Reference Dependence as a case study
    INSEAD Business School , Fontainebleau , France , January 2006
  • Process Tracing for Dummies: Solutions for design, analysis and presentation
    University of Amsterdam , Social Decision Making group, January 2006
  • Process Tracing for Dummies: Solutions for design, analysis and presentation
    Tilburg University , Economic and Social Psychology, December 2005
  • Negative-based prominence: The role of negative features in matching and choice
    SPUDM conference (organized by European Association of Decision Making), August 2001, Amsterdam

Conference presentations

  • The role of domain knowledge, interfaces and mindsets on energy-saving decisions made with a recommender system
    Paper presented at 25th Biennial Conference on Subjective Probability, Utility and Decision Making (SPUDM), August 16-20, 2015, Budapest, Hungary
  • Trumping discounting of future energy savings using "life time costs" choice architectures
    Paper presented at 13th TIBER Symposium on Psychology and Economics, August 22, 2014, Tilburg University
  • Using personalized recommendations to understand the role of diversity on choice overload.
    Paper presented at 24th Biennial Conference on Subjective Probability, Utility and Decision Making (SPUDM), 18-22 August, 2013, Barcelona, Spain
  • Recommending less is more: Understanding choice overload using a movie recommender System
    Poster presented at the 31st annual meeting of the Society for Judgment and Decision Making (JDM), Nov 19-22, 2010, St. Louis, MO
  • Information processes underlying the MPG-illusion
    Paper presented at 22th Biennial Conference on Subjective Probability, Utility and Decision Making (SPUDM), 23-27 August, 2009, Rovereto, Italy
  • The Why and When of Context Effects
    Paper presented within the ACR symposium: "Beyond 2x2x2: Methodological Advances in Uncovering Consumer Decision Processes"
    Association for Consumer Research conference, October 23-26, 2008, San Francisco, CA
  • Testing Cognitive models of context effects using process data
    Paper presented within the special session "Methodological Advances in Uncovering Consumer Decision Processes"
    37th European Marketing Academy (EMAC) conference, 27-30 May 2008, Brighton, UK
  • Comprehension checks as a necessary condition for validating experimental demonstrations of normative violations.
    Paper presented at the 28th annual meeting of the Society for Judgment and Decision Making (JDM), Nov 16-19, 2007 , Long Beach, CA
  • Consumer usage of positive and negative customer reviews in online decision making tasks
    Poster presented at the 28th annual meeting of the Society for Judgment and Decision Making (JDM), Nov 16-19, 2007 , Long Beach, CA
  • Testing cognitive models of context effects using process data
    Paper presented at the 27th annual meeting of the Society for Judgment and Decision Making (JDM), Nov 17-20, 2006 , Houston, TX
  • Process Tracing for Dummies: Solutions for design, analysis and presentation
    Paper presented at the 26th annual meeting of the Society for Judgment and Decision Making (JDM), Nov 11-14, 2005 , Toronto , Canada
  • Choice and Reject Strategies in Binary Decision Problems
    Paper presented at 20th Biennial Conference on Subjective Probability, Utility and Decision Making (SPUDM), 22-24 August, 2005, Stockholm , Sweden .
  • Do losses really loom larger than gains? A process perspective on loss aversion
    Paper presented at the 25th annual meeting of the Society for Judgment and Decision Making (JDM), Nov 19-22, 2004 , Minneapolis MN
  • MouselabWEB: Process tracing anywhere, anytime!
    Paper presented at the annual meeting of the Society for Computers in Psychology (SCIP), Nov 18, 2004 , Minneapolis MN
  • Do losses really loom larger than gains? A process perspective on loss aversion
    Paper presented at the 3rd Tilburg Symposium on Psychology and Economics: Games and Decisions, Tilburg (NL), Sept 1, 2004
  • Loss Aversion Has Two Faces
    Paper presentation at the 9th Behavioral Decision Research in Management Conference (BDRM), April 15-18, 2004 , Duke University 's Fuqua School of Business, Durham , NC
  • Asymmetric compatibility effects in choice and reject
    Poster presentation at the 24th annual meeting of the Society for Judgment and Decision Making (JDM), November 9-10, 2003 , Vancouver , BC Canada
  • Positive/Negative asymmetries underlying matching and choice
    Paper presentation with Gideon Keren at the 23rd annual meeting of the Society for Judgment and Decision Making (JDM), November 24-25, 2002 , Kansas City , MO
  • Advantage of A or disadvantage of B? Positive and negative facets in the description of choice options.
    Poster presentation at the 23rd annual meeting of the Society for Judgment and Decision Making (JDM), November 24-25, 2002, Kansas City, MO
  • Differential weighing of attributes in joint and separate evaluation: the role of negative features.
    Paper presentation at the 8th Behavioral Decision Research in Management Conference (BDRM), May 31 - June 1, 2002 , Chicago
  • The Good, the Bad, and the Ugly: Determinants of positive and negative features in choice
    Poster presentation at the 21st annual meeting of the Society for Judgment and Decision Making (JDM), November 18-20, 2000, New Orleans
  • Predicting the prominent attribute: The role of negative features in matching and choice
    Poster presentation at the 20th annual meeting of the Society for Judgment and Decision Making (JDM), November 21-23, 1999 , Los Angeles