Effect of a context shift on the inverse base-rate effect

Abstract

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

Errorless irrationality: removing error-driven components from the inverse base-rate effect paradigm

“…According to Classical Probability Theory, the rational response is to categorize this ambiguous combination under the common label, because it is the most frequently occurring label. This rare bias on ambiguous combinations of BC has been observed across a variety of experimental manipulations (Kalish, 2001;Don & Livesey, 2017Inkster, Mitchell, Schlegelmilch, & Wills, 2022;Wills, Lavric, Hemmings, & Surrey, 2014).…”

g-distance: On the comparison of model and human heterogeneity

“…However, when participants are sequentially trained and tested on a combination of conflicting cues, the group-level result is that participants prefer the rare category (Kruschke, 1996). The IBRE has been observed in many experiments across a range of G-DISTANCE 20 scenarios (e.g., Shanks, 1992;Don & Livesey, 2017;Inkster, Milton, Edmunds, Benattayallah, & Wills, 2021;Inkster, Mitchell, Schlegelmilch, & Wills, 2022;Johansen, Fouquet, & Shanks, 2007, 2010Kalish, 2001;Sherman et al, 2009;Wills, Lavric, Croft, & Hodgson, 2007); for an excellent recent review, see Don, Worthy, and Livesey (2021).…”

“…In the context of IBRE research, the paradigm example of an attentional-associative model is the EXemplar-based attention to distinctive InpuT (EXIT) model (Kruschke, 2001b). EXIT has been extensively examined through behavioral, eye-tracking, EEG, and fMRI methodologies, and is sometimes considered to be the most adequate of the available formal accounts of the IBRE (Don, Beesley, & Livesey, 2019;Don & Livesey, 2017;Inkster et al, 2021Inkster et al, , 2022Kruschke, 2001a;Wills et al, 2017). It is thus hard to imagine any assessment of the relative adequacy of models of the IBRE without including EXIT.…”

Zebra Reduction: Better Generalization Through Distraction

“…The attentional reallocation account has been formalized in the mathematical model EXIT (Kruschke, 2001b), which arguably provides the most complete account of the IBRE and associated phenomena (Don et al, 2019;Inkster, Mitchell, Schlegelmilch, & Wills, 2022;e.g. Kruschke, 2001ae.g.…”