Inkster, A.B., Mitchell, C.J., Schlegelmilch, R. and Wills, A.J. (2022). Effect of a context shift on the inverse base-rate effect. Open Journal of Experimental Psychology and Neuroscience, 1, 22-29. https://doi.org/10.46221/ojepn.2022.0404. First published: 25 April 2022.
The Inverse Base Rate Effect (IBRE) is a non-rational behavioural phenomenon in predictive learning. In the IBRE,
participants learn that a stimulus compound AB leads to one outcome and that another compound AC leads to a different
outcome. Importantly, AB and its outcome are presented three times as often as AC (and its outcome). On test, when asked which outcome to expect on presentation of the novel compound BC, participants preferentially select the rarer outcome, previously associated with AC. This is irrational because, objectively, the common outcome is more likely. Usually, the IBRE is attributed to greater attention paid to cue C than to cue B, and so is an excellent test for attentional learning models. The current experiment tested a simple account of attentional learning proposed by Le Pelley, Mitchell, Beesley, George, and Wills (2016) where attention paid to a stimulus is determined by its associative strength. This account struggles to capture the IBRE, but a potential solution presented by Le Pelley et al. (2016) appeals to the role of experimental context. In the present paper, we derived four predictions from the context explanation concerning the effect of changing to a novel experimental context at test, and examined these predictions empirically. Only one of the predictions, concerning the effect of a context shift on responding to a novel cue, was supported. These results fail to support both the context explanation suggested by Le Pelley et al. (2016) and the current leading account of the IBRE, EXIT (Kruschke, 2001b), but provide avenues for further research.
Keywords: Inverse base-rate effect, EXIT, predictive learning, categorization
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Edmunds, C.E.R., Inkster, A.B., Jones, P.M., Milton, F. and Wills, A.J. (2020). Absence of cross-modality analogical transfer in perceptual categorization. Open Journal of Experimental Psychology and Neuroscience, 1, 3-13. https://doi.org/10.46221/ojepn.2020.8639. First published: 7 August 2020.
Analogical transfer has been previously reported to occur between rule-based, but not information-integration, perceptual category structures (Casale, Roeder, & Ashby, 2012). The current study investigated whether a similar pattern of results would be observed in cross-modality transfer. Participants were trained on either a rule-based structure, or an information-integration structure, using visual stimuli. They were then tested on auditory stimuli that had the same underlying abstract category structure. Transfer performance was assessed relative to a control group who did not receive training on the visual stimuli. No cross-modality transfer was found, irrespective of the category structure employed.
Keywords: analogical reasoning, generalisation, strategies, learning, multiple systems
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Edmunds, C.E.R., Inkster, A.B., Jones, P.M., Milton, F. and Wills, A.J. (2020). Absence of cross-modality analogical transfer in perceptual categorization. (PDF)
Spicer, S.G., Wills, A.J., Jones, P.M., Mitchell, C.J. and Dome, L. (2021). Representing uncertainty in the Rescorla-Wagner model: Blocking, the redundancy effect, and outcome base rate. (PDF)
Inkster, A.B., Mitchell, C.J., Schlegelmilch, R. and Wills, A.J. (2022). Effect of a context shift on the inverse base-rate effect. (PDF)
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Spicer, S.G., Wills, A.J., Jones, P.M., Mitchell, C.J. and Dome, L. (2021). Representing uncertainty in the Rescorla-Wagner model: Blocking, the redundancy effect, and outcome base rate. Open Journal of Experimental Psychology and Neuroscience, 1, 14-21. https://doi.org/10.46221/ojepn.2021.6623 First published: 17 March 2021.
It is generally assumed that the Rescorla and Wagner (1972) model adequately accommodates the full results of simple cue competition experiments in humans (e.g. Dickinson et al., 1984), while the Bush and Mosteller (1951) model cannot. We present simulations that demonstrate this assumption is wrong in at least some circumstances. The Rescorla-Wagner model, as usually applied, fits the full results of a simple forward cue-competition experiment no better than the Bush-Mosteller model. Additionally, we present a novel finding, where letting the associative strength of all cues start at an intermediate value (rather than zero), allows this modified model to provide a better account of the experimental data than the (equivalently modified) Bush-Mosteller model. This modification also allows the Rescorla-Wagner model to account for a redundancy effect experiment (Uengoer et al., 2013); something that the unmodified model is not able to do. Furthermore, the modified Rescorla-Wagner model can accommodate the effect of varying the proportion of trials on which the outcome occurs (i.e. the base rate) on the redundancy effect (Jones et al., 2019). Interestingly, the initial associative strength of cues varies in line with the outcome base rate. We propose that this modification provides a simple way of mathematically representing uncertainty about the causal status of novel cues within the confines of the Rescorla-Wagner model. The theoretical implications of this modification are discussed. We also briefly introduce free and open resources to support formal modelling in associative learning.
Keywords: associative learning, prediction error, uncertainty, modelling, blocking, redundancy effect, open science.
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Plymouth University bursaries
The Cognition Institute, part of Plymouth University, U.K., has sponsored 10 full bursaries for postgrads and post-docs at the university, to cover the full Article Processing Charge at OJEPN. The bursaries may also extend to staff members of the university if they do not have access to other funds. These bursaries are administered by OJEPN on behalf of the university. They are allocated at point of paper acceptance, on a first-come, first-served basis.
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