ORCID Profile
0000-0003-2695-3013
Current Organisation
University of Tasmania
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Publisher: Springer Science and Business Media LLC
Date: 04-06-2015
DOI: 10.1007/S00426-015-0671-Z
Abstract: Successive lexical decisions have shown sequential effects where faster word responses and slower nonword responses follow the same versus different prior response. To date, explanations of these effects have been based on processes specific to discriminating words from nonwords. However, a more parsimonious explanation is possible, based on generic choice processes that apply even to left/right discriminations. Under conditions that promote automaticity, this explanation distinctly predicts equal facilitation by response repetition for words and nonwords. This hypothesis was here tested in an experiment involving 82 participants completing 850-trial blocks of lexical decision with a 100 ms response-stimulus interval-a much faster rate of choice succession than previously used-and including a factor of word/nonword discriminability so as to further test the applicability of choice-specific processes. Distinct from earlier findings, sequential effects were found to be identical in sign and substance for words and nonwords. This reliably occurred as facilitation by repetition across the decile distribution of response-times, across high and low levels of word/nonword discriminability, within each block of the run, and in interaction with higher-order sequential effects involving up to four prior trials. The main effect of facilitation by repetition at the second-order was particularly strong, being equal in effect-size to the interactive effect of the word/nonword factor and word/nonword discriminability (η (2) = 0.61). Hence, generic choice processes appeared to be sufficient to produce lexical decision sequential effects, independently of choice-specific processes. The findings particularly suggested a primary role for automatic response-facilitation, with accuracy-monitoring and expectancy contributing to higher-order effects. The further role of choice-specific processes in these and other findings, and the utility of lexical decision in studying generic choice processes, are discussed.
Publisher: American Psychological Association (APA)
Date: 09-2019
DOI: 10.1037/PAG0000339
Abstract: Base-rate neglect is a failure to sufficiently bias decisions toward a priori more likely options. Given cognitive and neurocognitive model-based evidence indicating that, in speeded choice tasks, (a) age-related slowing is associated with higher and less flexible overall evidence thresholds (response caution) and (b) gains in speed and accuracy in relation to base-rate bias require flexible control of choice-specific evidence thresholds (response bias), it was hypothesized that base-rate neglect might increase with age due to compromised flexibility, and so optimality, of response bias. We administered a computer-based perceptual discrimination task to 20 healthy older (63-78 years) and 20 younger (18-28 years) adults where base-rate direction was either variable or constant over trials and so required more or less flexible bias control. Using an evidence accumulation model of response times and accuracy (specifically, the Linear Ballistic Accumulator model Brown & Heathcote, 2008), age-related slowing was attributable to higher response caution, and gains in speed and accuracy per base-rate bias were attributable to response bias. Both age groups were less biased than required to achieve optimal accuracy, and more so when base-rate direction changed frequently. However, bias was closer to optimal among older than younger participants, especially when base-rate direction was constant. We conclude that older participants performed better than younger participants because of their greater emphasis on accuracy, and that, by making greater absolute and equivalent relative adjustments of evidence thresholds in relation to base-rate bias, flexibility of bias control is at most only slightly compromised with age. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Publisher: Center for Open Science
Date: 17-01-2022
Abstract: We propose a new cognitive-modelling methodology that disentangles the non-linear interactions among psychological mechanisms underpinning behaviour in a complex task. We apply the approach to the domain of cognitive aging and show that it affords simultaneous measures of the major mechanisms proposed to explain age-related deficits: capacity limits, processing speed, inhibition, and executive function. The measures’ validities derive from the precisely specified roles of the model parameters and the model’s comprehensive, detailed, and accurate account of the behaviour of our healthy older and younger participants. Because it derives constraint from all aspects of participant’s behaviour, the analysis is powerful enough to provide clear results from a relatively small s le of participants who provide high quality data. When controlling for all other factors, we identify processing speed as the primary cause of age-related deficits. Executive control was better for older than younger participants when task demands were lower, but as demands increased this advantage reduced or disappeared, consistent with age-related capacity limitations. We conclude that such detailed cognitive models have the potential to be widely applied to provide an integrated, quantitative, and conceptually rich account of the many interacting psychological mechanisms that support behaviour in complex tasks.
Publisher: American Psychological Association (APA)
Date: 2021
DOI: 10.1037/XGE0000770
Publisher: Center for Open Science
Date: 20-08-2019
Abstract: We propose a dynamic theory of decisions not to choose between two options. Such “don’t-know” judgements are of theoretical and practical importance in domains ranging from comparative psychology, psychophysics, episodic memory and metacognition to applied areas including educational testing and eyewitness testimony. However, no previous theory has provided a general account of both the time it takes to make both definitive and don't-know responses and their relative frequencies. We tested our theory, the “Multiple Threshold Race” (MTR), in one recognition memory experiments where participants had to pick a previously studied target out of two similar faces and another where targets and lures were tested one at a time. High similarity made decisions difficult, encouraging don't-know responses, and we manipulated similarity through face morphing. We also tested the MTR’s ability to account for other manipulations that aimed to affect the speed and probability of don't-know responses, including increasing penalties for making an error (with no penalty for a don't-know response) and emphasising either response speed or accuracy. We found that there were marked in idual differences in don't-know use, and that the MTR was able to provide a detailed account of the intricate pattern of effects associated with our manipulations, both on average and in terms of in idual differences. We discuss how estimates of MTR’s parameters illuminate the psychological mechanisms that govern the interplay between definitive and don't-know responding.
No related grants have been discovered for Roderick Garton.