November 16, 2024	How do people search for information before making choices? Theoretical approaches suggest that decision makers’ primary aim is reducing the uncertainty surrounding aspects such as an option’s average value; however, this view has rarely been tested using empirical data. This article reports a data-driven analysis of a large-scale, publicly available dataset aiming to identify the drivers of information search. It reveals that people use their prior expectations and environmental knowledge to adaptively reduce at least three types of uncertainty: structural uncertainty concerning features of the decision environment, estimation uncertainty surrounding options’ average rewards, and computational uncertainty arising from the difficulty of information processing. The findings highlight how information search is more complex and adaptive than portrayed by current theoretical accounts. Out now in PNAS. A summary (https://x.com/Mikhail_Spektor/status/1857676982974062671) and a link to the paper (open access; https://doi.org/10.1073/pnas.2311714121)
September 04, 2024	Very happy to announce that I joined the College of Arts and Sciences at VinUniversity as an Assistant Professor and Acting Program Director (Psychology)!
July 19, 2024	Almost all e-commerce platforms offer the possibility for consumers to express their satisfaction with their purchases by writing product reviews. How do people decide what to write about? We find that people are influenced by other reviews that are visible at the time of review writing, but only if they were rated as helpful by other community members. We show that this process is a product of directed imitation rather than a bottom-up influence, and that reviews that imitate helpful reviews tend to receive more helpfulness ratings themselves. Out now in Decision. A summary (https://x.com/Mikhail_Spektor/status/1814058161684496402)
March 15, 2024	What is people's attitude towards the (a)symmetry of outcomes? Depending on which literature you consult, you will get different answers. Research in finance and using risky choices suggests that people like options "lottery-like" options that provide small wins most of the time but sometimes very large wins. On the other hand, experimental research into experience-based choices suggests the exact opposite pattern. We reconcile these seemingly contradictory findings by showing how the comparison of outcomes can mask the intrinsic preferences towards skewness. Very proud of this publication! Out now in PNAS. A summary (https://x.com/Seb_Olschewski/status/1768703691219947709) and press release (https://www.unibas.ch/en/News-Events/News/Uni-Research/How-comparison-options-affect-stock-buys.html)
December 07, 2023	"Losses loom larger than gains", or do they? Our investigation into the absolute and relative stability of loss aversion across contexts is out now in Journal of Experimental Psychology: General. A summary: https://twitter.com/Mikhail_Spektor/status/1732810708272779387
June 12, 2023	I haven't updated the website in a long while... It should be up-to-date now.
Jun 11, 2023	New preprint: How do people explore options before making a choice? In an analysis of over 1M sampling decisions, Dirk Wulff and I show that people rely on a toolbox of search strategies in an adaptive and dynamic way: https://doi.org/10.31234/osf.io/7ru58
Feb 16, 2023	New preprint: How stable is loss aversion, really? When it changes across different contexts, is the rank order maintained? We investigate this question in our newest preprint: https://doi.org/10.31234/osf.io/cwm2s
May 18, 2022	How are context effects in perceptual decision making (such as judging the length of a line) and preferential decision making (such as choosing what to buy for lunch) related to each other? We investigated this question with a focus on information-processing strategies using eye-tracking methodology and computational modeling. Out now in Cognition. A summary: https://twitter.com/Mikhail_Spektor/status/1526970175744008199
April 01, 2022	Today, I joined the Department of Psychology at the University of Warwick as an Assistant Professor. Looking forward to working with many great colleagues!
March 30, 2022	In many situations, people have to filter out relevant and ignore irrelevant information. Past research (e.g., the anchoring effect) has shown that even entirely irrelevant information can have an impact on choices. In a new paper, we looked at whether people are able to successfully filter out relevant information in an experience-based learning task, and we found that sometimes they cannot do that effectively. Out now in Judgment and Decision Making: http://journal.sjdm.org/21/210616/jdm210616.pdf (open access).
August 20, 2021	How exactly do contextual features affect human decisions? Things are complicated and many findings contradict each other. Our proposal for a solution out now in Trends in Cognitive Sciences. A summary: https://twitter.com/Mikhail_Spektor/status/1429813685342642181
January 30, 2021	How do individuals make decisions from experience when reckless behaviors are taxed? Reckless behaviors, such as texting while driving, are in most cases harmless but sometimes lead to catastrophic outcomes. We show that myopic individuals who disregard catastrophic outcomes soon after they have been experienced are particularly affected by over-taxation. A policy targeted at these individuals — for example, by using boosts — could be effective over and beyond omnibus taxation interventions. Out now in Judgment and Decision Making: https://sjdm.org/journal/20/200526a/jdm200526a.pdf (open access).
September 28, 2020	Our paper that compares single- and dual-process evidence accumulation models of memory-based decisions out now in Psychonomic Bulletin & Review: https://doi.org/10.3758/s13423-020-01794-9 (open access). Also, check out the summary of the paper as a Twitter thread and conference talk.
September 23, 2020	New preprint (together with David Kellen and Karl Christoph Klauer) about the project I'll present at the ViProc available on PsyArXiv: https://doi.org/10.31234/osf.io/hmzsx
September 22, 2020	I will present my recent work about the repulsion effect in preferential and perceptual choice at the Virtual Process Tracing (ViProc) Conference 2020. Also, I will try to update the news section of this website more often.
April 16, 2020	Due to the Covid-19 pandemic, the 5th EADM summer school has been postponed to next year. More information: ldmss.org
January 31, 2020	Save the date for the 5th EADM summer school on the topic of learning and decision making! More information on our website: ldmss.org
July 04, 2019	I will present my recent work with the short title "Violations of economic rationality in reinforcement learning are driven by a saliency-dependent reward-prediction-error signal in the ventral striatum" at the Neuroeconomics in Dublin.
May 13, 2019	New website, still very much under construction.
January 10, 2019	I will be joining the Universitat Pompeu Fabra as an assistant professor in September 2019.

Humans face many different kinds of decisions in their everyday lives, such as what to eat for lunch or where to go on vacation. Attempts to understand the principles underlying such decisions traditionally involve an axiomatic system of preferences and are often used as the benchmark for economically "rational" human behavior. I am particularly interested in behavior that deviates from such notions of rationality as I believe that those situations provide an important window to human cognition.

In my main line of research, I investigate the cognitive processes underlying such "irrational behavior" with a particular focus on the role of attention in the formation of context-dependent preferences, so-called context effects. I rely on formal modeling of cognition and combine it with evidence from behavioral experiments and psychophysiological data to obtain a more comprehensive understanding of the cognitive processes underlying human decision making.

Decisions under risk and uncertainty

Learning and decision making

Context-dependent preferences

Cognitive modeling

Spektor, M. S.*, & Wulff, D. U.* (2024). Predecisional information search adaptively reduces three types of uncertainty. Proceedings of the National Academy of Sciences, 121(47), e2311714121, https://doi.org/10.1073/pnas.2311714121

Alba, C., Walasek, L., & Spektor, M. S. (2024). Attention-driven imitation in consumer reviews. Decision, 1–11. https://doi.org/10.1037/dec0000238

Olschewski, S.*, Spektor, M. S.*, & Le Mens, G. (2024). Frequent winners explain apparent skewness preferences in experience-based decisions. Proceedings of the National Academy of Sciences, 121(12), e2317751121, https://doi.org/10.1073/pnas.2317751121

Spektor, M. S.*, Kellen, D.*, Rieskamp, J., & Klauer, K. C. (2024). Absolute and relative stability of loss aversion across contexts. Journal of Experimental Psychology: General, 153(2), 454-472, https://doi.org/10.1037/xge0001513

Spektor, M. S., Kellen, D., & Klauer, K. C. (2022). The repulsion effect in preferential choice and its relation to perceptual choice. Cognition, 225, 105164, https://doi.org/10.1016/j.cognition.2022.105164

Spektor, M. S., & Seidler, H. (2022). Violations of economic rationality due to irrelevant information during learning in decision from experience. Judgment and Decision Making, 17(2), 425–448. http://journal.sjdm.org/21/210616/jdm210616.pdf

Spektor, M. S., Bhatia, S., & Gluth, S. (2021). The elusiveness of context effects in decision making. Trends in Cognitive Sciences, 25(10), 844–857. https://doi.org/10.1016/j.tics.2021.07.011.

Voormann, A., Spektor, M. S., & Klauer, K. C. (2021). The simultaneous recognition of multiple words: A process analysis. Memory & Cognition, 49(4), 787–802. https://doi.org/10.3758/s13421-020-01082-w.

Spektor, M. S., & Wulff, D. U. (2021). Myopia drives reckless behavior in response to over-taxation. Judgment and Decision Making, 16(1), 114–130. https://sjdm.org/journal/20/200526a/jdm200526a.pdf

Kraemer, P., Fontanesi, L., Spektor, M. S., & Gluth, S. (2020). Response time models separate single- and dual-process accounts of memory-based decisions. Psychonomic Bulletin & Review, 28(1), 304–323. https://doi.org/10.3758/s13423-020-01794-9

Fontanesi, L., Gluth, S., Spektor, M. S., & Rieskamp, J. (2019). A reinforcement learning diffusion decision model for value-based decisions. Psychonomic Bulletin & Review, 26(4), 1099–1121. https://doi.org/10.3758/s13423-018-1554-2

Spektor, M. S., Gluth, S., Fontanesi, L., & Rieskamp, J. (2019). How similarity between choice options affects decisions from experience: The accentuation of differences model. Psychological Review, 126(1), 52–88. https://doi.org/10.1037/rev0000122

Gluth, S.*, Spektor, M. S.*, & Rieskamp, J. (2018). Value-based attentional capture affects multi-alternative decision making. eLife, 7, 1–36. https://doi.org/10.7554/eLife.39659

Spektor, M. S., Kellen, D., & Hotaling, J. M. (2018). When the good looks bad: An experimental exploration of the repulsion effect. Psychological Science, 29(8), 1309–1320. https://doi.org/10.1177/0956797618779041

Spektor, M. S., & Kellen, D. (2018). The relative merit of empirical priors in non-identifiable and sloppy models: Applications to models of learning and decision-making. Psychonomic Bulletin & Review, 25(6), 2047–2068. https://doi.org/10.3758/s13423-018-1446-5.

Spektor, M. S., & Yuan, T. (2020). Digitalisierung in der Juristenausbildung. Neue Juristische Wochenschrift, 15, 52–88.

As a behavioral scientist, I am fascinated by all the different facets and the complexity of human cognition. Every new discovery not only uncovers part of that complex puzzle but also reveals more uncharted waters ahead of us. I believe that this curiosity of wanting to obtain a deeper understanding of the human nature is the main driving force behind both good research and learning success.

I offer supervision of theses. If you are interested in working on any of my research topics, feel free to contact me.

I am currently teaching three undergraduate courses (Social Psychology, Cognitive Psychology, Research Methods in Psychology).