Shane T. Mueller

The Psychology Experiment Building Language (PEBL) and PEBL Test Battery

BACKGROUND We briefly describe the Psychology Experiment Building Language (PEBL), an open source software system for designing and running psychological experiments. NEW METHOD We describe the PEBL Test Battery, a set of approximately 70 behavioral tests which can be freely used, shared, and modified. Included is a comprehensive set of past research upon which tests in the battery are based. RESULTS We report the results of benchmark tests that establish the timing precision of PEBL. COMPARISON WITH EXISTING METHOD We consider alternatives to the PEBL system and battery tests. CONCLUSIONS We conclude with a discussion of the ethical factors involved in the open source testing movement.

Theoretical implications of articulatory duration, phonological similarity, and phonological complexity in verbal working memory.

The phonological-loop model provides a prominent theoretical description of verbal working memory. According to it, serial recall accuracy should be inversely related to the articulatory duration and phonological similarity of verbal items in memorized sequences. Initial tests of these predictions by A. D. Baddeley and colleagues (e.g., A. D. Baddeley, N. Thomson, & M. Buchanan, 1975) appeared to support the phonological-loop model, but subsequent researchers have obtained conflicting data that putatively disconfirm its assumptions. Such conflicts may have stemmed from less than ideal measurements of articulatory duration and phonological similarity. This article discusses these concerns and proposes new theoretically principled methods for measuring articulatory duration and phonological similarity. Two experiments that used these methods in the context of a verbal serial recall task are reported. The results of these experiments confirm and extend the predictions of the phonological-loop model while disarming previous criticisms of it.

Decision noise: An explanation for observed violations of signal detection theory

In signal detection theory (SDT), responses are governed by perceptual noise and a flexible decision criterion. Recent criticisms of SDT (see, e.g., Balakrishnan, 1999) have identified violations of its assumptions, and researchers have suggested that SDT fundamentally misrepresents perceptual and decision processes. We hypothesize that, instead, these violations of SDT stem from decision noise: the inability to use deterministic response criteria. In order to investigate this hypothesis, we present a simple extension of SDT—the decision noise model—with which we demonstrate that shifts in a decision criterion can be masked by decision noise. In addition, we propose a new statistic that can help identify whether the violations of SDT stem from perceptual or from decision processes. The results of a stimulus classification experiment—together with model fits to past experiments—show that decision noise substantially affects performance. These findings suggest that decision noise is important across a wide range of tasks and needs to be better understood in order to accurately measure perceptual processes.

Models of Working Memory: Insights into Working Memory from the Perspective of the EPIC Architecture for Modeling Skilled Perceptual-Motor and Cognitive Human Performance

Abstract : Computational modeling of human perceptual-motor and cognitive performance based on a comprehensive detailed information- processing architecture leads to new insights about the components of working memory. To illustrate how such insights can be achieved a precise production system model that uses verbal working memory for performing a serial memory-span task through a strategic phonological loop has been constructed with the Executive-Process/ Interactive-Control (EPIC) architecture of Kieras and Meyer. The model accounts well for empirical results from representative memory-span studies The success of this account stems from five central features of EPIC that may be compared and contrasted with those of other currently popular alternative theoretical frameworks.

Executive-process interactive control: A unified computational theory for answering 20 questions (and more) about cognitive ageing

Although the effects of ageing on human information processing and performance have been studied extensively, many fundamental questions about cognitive ageing remain to be answered definitively. For example, what are the sources of age-related slowing? How much is working-memory capacity reduced in older adults? Is time-sharing ability lost with age? Answering such questions requires a unified computational theory that characterises the interactive operations of many component mental processes and integrates diverse data on cognitive ageing. Toward fulfilling this requirement, an executive-process interactive control (EPIC) architecture has been extended to model performance of both young and older adults. EPIC models yield accurate accounts of ageing effects on reaction times and accuracy in basic dual-task and working-memory paradigms. From these accounts, it appears that time-sharing ability and working-memory capacity decrease relatively little until after 70 years of age. Before age 70, at least som...

Alphabetic letter identification: Effects of perceivability, similarity, and bias

The legibility of the letters in the Latin alphabet has been measured numerous times since the beginning of experimental psychology. To identify the theoretical mechanisms attributed to letter identification, we report a comprehensive review of literature, spanning more than a century. This review revealed that identification accuracy has frequently been attributed to a subset of three common sources: perceivability, bias, and similarity. However, simultaneous estimates of these values have rarely (if ever) been performed. We present the results of two new experiments which allow for the simultaneous estimation of these factors, and examine how the shape of a visual mask impacts each of them, as inferred through a new statistical model. Results showed that the shape and identity of the mask impacted the inferred perceivability, bias, and similarity space of a letter set, but that there were aspects of similarity that were robust to the choice of mask. The results illustrate how the psychological concepts of perceivability, bias, and similarity can be estimated simultaneously, and how each make powerful contributions to visual letter identification.

A PARTIAL IMPLEMENTATION OF THE BICA COGNITIVE DECATHLON USING THE PSYCHOLOGY EXPERIMENT BUILDING LANGUAGE (PEBL)

The Cognitive Decathlon is a proposed set of tasks that can be tested on both human and artificially intelligent agents, and which constitutes a modern specification for the Turing Test. In this paper, a partial implementation of the Cognitive Decathlon is described using the Psychology Experiment Building Language (PEBL). The tasks focus not simply on generic human abilities, but on critical skills that highlight aspects of human performance that are at odds with common artificial intelligence approaches. The differences between human and algorithmic behavior in such tasks can reveal properties of the human cognitive architecture, and production of similar behavior by artificial systems can help constrain and validate biologically-inspired systems.

A Bayesian Recognitional Decision Model

The recognition-primed decision (RPD) model (Klein, 1993) is an account of expert decision making that focuses on how experts recognize situations as being similar to past experienced events and thus rely on memory and experience to make decisions. A number of computational models exist that attempt to account for similar aspects of expert decision making. In this paper, I briefly review these extant models and propose the Bayesian recognitional decision model (BRDM), a Bayesian implementation of the RPD model based primarily on models of episodic recognition memory (Mueller & Shiffrin, 2006; Shiffrin & Steyvers, 1997). The proposed model accounts for three important factors used by experts to make decisions: evidence about a current situation, the prior base rate of events in the environment, and the reliability of the information reporter. The Bayesian framework integrates these three aspects of information together in an optimal way and provides a principled framework for understanding recognitional decision processes.

Evaluation of a Short-Form of the Berg Card Sorting Test

The Psychology Experimental Building Language http://pebl.sourceforge.net/ Berg Card Sorting Test is an open-source neurobehavioral test. Participants (N = 207, ages 6 to 74) completed the Berg Card Sorting Test. Performance on the first 64 trials were isolated and compared to that on the full-length (128 trials) test. Strong correlations between the short and long forms (total errors: r = .87, perseverative response: r = .83, perseverative errors r = .77, categories completed r = .86) support the Berg Card Sorting Test-64 as an abbreviated alternative for the full-length executive function test.

Functional Polymorphisms in BDNF and COMT Genes Are Associated with Objective Differences in Arithmetical Functioning in a Sample of Young Adults

Background: Understanding the molecular genetics of complex human behaviors and functions remains a substantial challenge for the neurosciences. Previous studies have shown a genetic basis for individual differences in mathematical functioning; however, the specific genes remain to be completely identified. In the present study, we explored the possibility that 2 functional polymorphisms in candidate genes could be associated with differences in arithmetical performance. Methods: A computerized test to analyze performance in basic arithmetical calculations (additions and subtractions) was applied to 168 healthy young Colombian participants using the PEBL (Psychology Experiment Building Language) battery. DNA samples were genotyped for 2 functional SNPs in candidate genes: brain-derived neurotrophic factor (BDNF)-Val66Met and catechol-O-methyltransferase (COMT)-Val158Met. Results: We found significant differences for arithmetical processing scores between genotypes. For BDNF, Val/Val subjects had a worse performance (p value: 0.025) and for COMT, Val/Val carriers had a better performance (p value: 0.006). A multivariate model, including both BDNF and COMT genes, accounted for 7.1% of the variance in math processing scores. Discussion: To our knowledge, this is the first study finding associations of polymorphisms in BDNF and COMT genes with quantitative measures of numerical aptitude in healthy young participants. A future study of other genes involved in neural plasticity could be helpful to identify genetic correlates of arithmetical functioning, which will be important for the understanding of normal human behaviors and related neuropsychiatric disorders.