Previous Research Themes
- Over/Underconfidence in Confidence Judgments
- Calibration and Diagnosticity of Confidence in Witness Identification
- The Cognitive Processes Involved in Multiple-cue Judgment
- The Naïve Intuitive Statistician
- Linear Additive Integration as the Cause of Judgment Biases
- Visual Information Integration
- Capacity Limits of Visual Working Memory
- Perception of Numbers
Over/Underconfidence in Confidence Judgments
The project applied theories that were inspired by the ideas of Egon Brunswik and L. L. Thurstone to explain the overconfidence bias observed for general knowledge items and the underconfidence bias observed in sensory discrimination, as well as to the hindsight bias. One theme of this research was that the biases diminish or disappear when you sample the tasks to be representative of a natural environment (c.f. Brunswik’s notion of representative design).
(Supported by The Swedish Research Council.)
Publications
- Juslin, P., & Olsson, H. (1997). Thurstonian and Brunswikian origins of uncertainty in judgment: A sampling model of confidence in sensory discrimination. Psychological Review, 104, 344-366.
- Juslin, P., Winman, A., & Olsson, H. (2000). Naive empiricism and dogmatism in confidence research: A critical examination of the hard-easy effect. Psychological Review, 107, 384-396.
- Winman, A., Juslin, P., & Björkman, M. (1998). The confidence-hindsight mirror effect in judgment: An accuracy-assessment model for the Knew-It-All-Along effect. Journal of Experimental Psychology: Learning, Memory, and Cognition, 24, 415-431.
Calibration and Diagnosticity of Confidence in Witness Identification
The project challenged (and refuted) the then prevalent view that there is no relationship between confidence and accuracy in eyewitness identification, both with empirical studies and new methods of analysis. We compared the calibration and diagnosticity of confidence in eyewitness and earwitness identification, while also addressing a number of other related issues.
(Supported by The Swedish Research Council.)
Publications
- Juslin, P., Olsson, N., & Winman, A. (1996). Calibration and diagnosticity of confidence in eyewitness identification: Comments on what can be inferred from the low confidence-accuracy correlation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 22, 1304–1316.
- Olsson, N., & Juslin, P. (1999). Can encoding strategy and self-reported recognition skill be diagnostic of performance in eyewitness identifications? Journal of Applied Psychology, 84, 42-49.
- Olsson, N., Juslin, P., & Winman, A. (1998). Realism of confidence in eyewitness vs. earwitness identification. Journal of Experimental Psychology: Applied, 4, 101-118.
The Cognitive Processes involved in Multiple-cue Judgments
The project applied theories and cognitive modeling techniques inspired by research on categorization learning to better understand the cognitive processes that underlie multiple-cue judgment. The results suggest that there is a flexible division of labor between explicit rule-based cognitive processes and exemplar-based processes, where people change process depending on the properties of the task environment (e.g., whether it is linear, additive or nonlinear).
(Supported by the Swedish Research Council and the Swedish Tercentary Bank Foundation)
Publications
- Juslin, P., Olsson, H., & Olsson, A-C. (2003). Exemplar effects in multiple-cue judgment. Journal of Experimental Psychology: General, 132-133-156.
- Juslin, P., Karlsson, L., & Olsson, H. (2008). Information integration in multiple-cue judgment: A division-of-labor hypothesis. Cognition, 106, 259-298.
- Olsson. A-C., Enkvist, T., & Juslin, P. (2006). Go with the flow! How to master a nonlinear judgment task. Journal of Experimental Psychology: Learning Memory and Cognition, 32, 1371-1384.
The Naïve Intuitive Statistican
The traditional way to explain judgment biases is by postulating mental mechanisms that can account for the observed deviations from the “rational” response (e.g., intensional heuristics or motivational biases). This project explored an alternative approach to judgment biases, inspired by the work of Klaus Fiedler, according to which people typically describe the samples they encounter in an unbiased and correct manner, but the biases arise (for a variety of reasons) in the relationship between the proximal samples people obtain and their natural environments.
(Supported by The Swedish Research Council.)
Publications
- Juslin, P., Winman, A., & Hansson, P. (2007). The naïve intuitive statistician: A naïve sampling model of intuitive confidence intervals. Psychological Review, 114, 678-703.
- Fiedler, K., & Juslin, P. (Eds.) (2006). Information sampling and adaptive cognition. New York: Cambridge University Press. [url]
- Lindskog, M., Winman, A., & Juslin, P. (2013). Naïve point estimation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 39, 782-800.
Linear Additive Integration as the Cause of Judgment Biases
A standard explanation of judgment biases, such as the conjunction fallacy and base-rate neglect, is that people rely on intentional (subjective) heuristics rather than probability theory. The current project argued (and demonstrated) that in many circumstances the real cause lies not primarily in the use of the one or the other intensional heuristic, but in the more general inability to perform the multiplicative information integration required by probability theory in many of these tasks.
(Supported by The Swedish Research Council.)
Publications
- Juslin, P., Nilsson, H. & Winman, A. (2009). Probability theory: Not the very guide of life. Psychological Review, 116, 856-874.
- Nilsson, H., Winman, A., Juslin, P. & Hansson, G. (2009). Linda is not a bearded lady: Configural weighting and adding as the cause of extension errors. Journal of Experimental Psychology: General, 138, 517-534.
- Nilsson, H., Juslin, P., & Winman, A. (2016). Heuristics can produce Surprisingly Rational Probability Estimates: Comments on Costello and Watts (2014). Psychological Review, 123, 103-111.
Visual Information Integration
The aim of one of the previous research projects was to use psychophysical methods to test visual information integration models. Our visual system can distinguish shapes against the background (figure-ground segregation) from contrasts in attributes such as brightness, color, texture, motion and stereoscopic depth. Are these features processed independently (in line with race models) or are they combined to activate a common channel (in line with co-activation models)? These models can be distinguished empirically by comparing results (response times) from conditions where two features are combined with corresponding conditions where the features are used in isolation. In laboratory settings, where images are generated by a computer and displayed on a screen, different attributes can be used in isolation or combined in controlled conditions. In typical experiments the task may be to localize or identify some target embedded in noise elements. The target may be an individual element (used to examine information integration in element detection) or multiple elements forming a specific pattern (used to examine information integration in gestalt formation). These two processes are believed to occur sequentially in the visual system. The variables under investigation are the attributes used either in isolation or combined to display the target and the dependent variables are response times and the percent correct responses.
(Supported by The Swedish Research Council.)
Publications
- Poom, L. (2011). Motion and color generate coactivation at postgrouping identification stages. Attention, Perception, & Psychophysics, 73, 1833-1842.
- Poom, L. (2009). Integration of color, motion, orientation and spatial frequency in visual search. Perception. 38, 708-718.
- Poom, L. (2003). Binding three kinds of vision. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Social Sciences, 121.
Capacity Limits in Visual Working Memory
We (Henrik Olsson & Leo Poom) investigated limitations and precision of the human visual working memory (VWM). In the literature on working memory, a prominent theme is its limited capacity. In regard to visual working memory, earlier methods may have overestimated capacity measures by the possibility of using verbal strategies, categorization, and long term memory. When the influence of other processes and representations besides the visual ones were minimized, our results indicate that the capacity of VWM is only one object. This is in contrast to recent capacity estimates of around four easily categorized objects such as, for example, squares and triangles. Although our VWM capacity is limited to about one item, we have demonstrated long-lasting acuity during the memory phase when holding just one item in VWM. Whether these results are the result of a fixed memory-slot-system or a memory system with dynamically allocated resources was not addressed.
(Supported by the Swedish Tercentary Bank Foundation)
Publications
- Poom, L. (2012). Memory of gender and gait-direction from biological motion patterns: Gender fade away but directions stay. Journal of Experimental Psychology: Human Perception and Performance, 38, 1091-1097.
- Diamantoupoulou, S., Poom, L., Klaver, P., & Talsma, D. (2011). Visual working memory capacity and stimulus categories: A behavioral and electrophysiological investigation. Experimental Brain Research, 209, 501-513.
- Olsson, H., & Poom, L. (2005). Visual memory needs categories. Proceedings of the National Academy of Sciences of the USA, 102, 8776-8780.
Perception of Numbers
It is claimed that the precision of non-symbolic numerosity comparisons lays the foundation for our formal mathematics achievement, and is coded within a modal invariant Approximate Number System (ANS). This project aims to properly understand the nature of non-symbolic number representation and its relation to other cognitive abilities. Psychophysical methods on humans are applied to estimate ANS-acuity. In typical studies ANS acuity is then correlated with other mental abilities. For example we demonstrated that individuals high in math anxiety (MA) have poorer ANS functioning than those low in MA, i.e. a relation between perception and MA. We also reported a new time-order effect in sequential presentation of stimuli in visual numerosity discrimination and judgment tasks, and quite large individual variations in the susceptibility of this effect. While cognitive and developmental scientists have been concerned with the relationship between numerosity accuracy and cognitive abilities, vision scientists have aimed their effort on the visual aspects of numerosity stimuli. This project bridges these fields and contributes to a deeper understanding of how we represent and process numbers and magnitudes and study how core knowledge systems may serve as a basis for formal knowledge systems, which in the end may help to improve mathematics education.
(Supported by the Swedish Research Council.)
Publications
- Van den Berg, R., Lindskog, M., Poom, L., & Winman, A. (2017). Recent Is More: A Negative Time-Order Effect in Nonsymbolic Numerical Judgment. Journal of Experimental Psychology: Human Perception and Performance.
- Lindskog, M., Winman, A., & Poom, L. (2017). Individual differences in nonverbal number skills predict math anxiety. Cognition, 159, 156–162. [SVT news article]