Professor Ami Eidels

Numerals are part of our everyday lives and are regularly viewed in less-than ideal conditions. Mistaking one numeral for another is almost an inevitability, and the cost of these confusions could be insignificant or hugely expensive! Numeral confusions can be explained by distances between our mental representations ¿ how we internally represent the external world ¿ resulting from their perceived similarities; yet, how expertise interacts with the mental space of numerals is largely unexplored. We used an identification paradigm to investigate the mental representations of familiar and unfamiliar numerals (4 sets: Arabic, Chinese, Thai, and non-symbolic dots) in a first-language English and a first-language Chinese speaking cohort. Using Luce¿s choice model, we removed the undesired effect of response bias and conducted multidimensional scaling analyses. Results showed that expertise with numerals alters distances in the mental space, that unfamiliar numerals are represented identically across cultures, that non-symbolic numerals (dots) may be represented both perceptually and numerically in the mental space, and that Arabic, Thai and Chinese numerals are represented by their perceptual similarities. The findings and methods of this study provide a principled foundation for future investigations into how expertise shapes people¿s mental representations.

User interfaces often utilise imagery of pristine natural environments, even if the system¿s purpose and context are unrelated to nature. In this paper, we build on evolutionary psychology to develop a theoretical model for the influence of nature imagery on user perceptions of trust, visual aesthetics, and purchase intentions in a corporate sales setting. We evaluate our model by means of an online experiment (n = 408) using a website with different configurations of nature imagery. The results provide support for our theoretical model and hence confirm a positive influence of nature presence, that is, the extent to which the website allows a user to experience the natural environment as being present, on trust, visual aesthetics, and purchase intentions. Thereby, user perceptions of nature presence are specifically linked to nature imagery depicting water as well as vegetation. This study furthers our understanding of how the environmental context of on-site imagery can have subtle information processing benefits for users. For practitioners this study offers insight to the types of imagery that could be utilised more effectively in corporate interface designs.

Assessing the cognitive impact of user interfaces is a shared focus of human-computer interaction researchers and cognitive scientists. Methods of cognitive assessment based on data derived from the system itself, rather than external apparatus, have the potential to be applied in a range of scenarios. The current study applied methods of analyzing kinematics to mouse movements in a computer-based task, alongside the detection response task, a standard workload measure. Sixty-five participants completed a task in which stationary stimuli were tar;geted using a mouse, with a within-subjects factor of task workload based on the number of targets to be hovered over with the mouse (one/two), and a between-subjects factor based on whether both targets (exhaustive) or just one target (minimum-time) needed to be hovered over to complete a trial when two targets were presented. Mouse movement onset times were slower and mouse movement trajectories exhibited more submovements when two targets were presented, than when one target was presented. Responses to the detection response task were also slower in this condition, indicating higher cognitive workload. However, these differences were only found for participants in the exhaustive condition, suggesting those in the minimum-time condition were not affected by the presence of the second target. Mouse movement trajectory results agreed with other measures of workload and task performance. Our findings suggest this analysis can be applied to workload assessments in real-world scenarios.

This study builds on previous research, which established that in flight simulator experiments the communication performance of pilots was impaired under certain applied conditions. The flight simulator data recording relating to the actions of the pilots were examined to determine the impact of the factors affecting pilots¿ communication (increased workload, increased demand on memory and, for some groups, increased ATC speech rate) on their flying performance. Using heading error as the dependent variable, no significant effects were found even for flights where pilots committed the most communication errors. Pilots are taught to prioritise tasks in order of operational safety importance, as per the adage ¿aviate, navigate, communicate¿. Thus, these results are encouraging as they show that the order of operational importance is adhered to, and that flying performance is maintained even when communication is affected.

22q11.2 deletion syndrome (22q11DS) is a neurodevelopmental disorder caused by a microdeletion on the long arm of chromosome 22. Sleep problems have been reported in this population, and psychiatric disorders and affect dysregulation are common to the behavioral phenotype of 22q11DS. Sleep and affect have been consistently linked across multiple studies, yet despite this very little research has investigated sleep problems in 22q11DS, or the link between sleep and affect in this population. The Experience Sampling Method was used to track daily reports of sleep quality and affect in a total of 29 individuals with 22q11DS and 21 control subjects. Measurements were recorded during a 6-day period using an electronic device that prompted daily response with audio cues. Participants with 22q11DS were found to experience a longer sleep onset latency and a greater amount, and duration, of night wakings compared with control subjects. Despite this, no significant between-group difference was found for subjective sleep quality. 22q11DS participants reported more experiences of negative affect and less positive affect than control subjects. A bidirectional relationship was found between sleep measures and affect. Sleep problems can cause a wide range of negative health effects, and individuals with 22q11DS are particularly vulnerable to deficits of sleep. To ensure high standards of care, healthcare providers should be aware of the possibility and impact of sleep problems in this population.

The present study used Systems Factorial Technology (Townsend & Nozawa, 1995) to investigate howpeople combine dual cues in semantic memory search. Our aims were (a) to understand how cues interactduring the process of semantic search in convergent thinking and (b) to determine how workloadcapacity (i.e. cue-processing efficiency) is related to search performance. In two experiments, participantscompleted a typical convergent thinking test and a word production task. The results revealedthat: (a) collective evidence supports similar patterns in cue-combination strategy despite individual differencesin workload capacity, and (b) there exists a negative correlation between workload capacityand performance on convergent thinking test. A potential explanation is that, for the creative individual,loading many candidate answers leads to consumption of substantial processing resources that obtainsas low workload capacity but also allows creative individuals to switch more easily from one candidateto another so that there is a higher probability of successfully producing an answer within a limitedtime. Our results further imply that workload capacity is a significant factor for the semantic search processin convergent thinking and provides new insight on the model of semantic search and creativity.

Cognitive workload is assumed to influence performance due to resource competition. However, there is a lack of evidence for a direct relationship between changes in workload within an individual over time and changes in that individual¿s performance. We collected performance data using a multiple object-tracking task in which we measured workload objectively in real-time using a modified detection response task. Using a multi-level Bayesian model controlling for task difficulty and past performance, we found strong evidence that workload both during and preceding a tracking trial was predictive of performance, such that higher workload led to poorer performance. These negative workload-performance relationships were remarkably consistent across individuals. Importantly, we demonstrate that fluctuations in workload independent from the task demands accounted for significant performance variation. The outcomes have implications for designing real-time adaptive systems to proactively mitigate human performance decrements, but also highlight the pervasive influence of cognitive workload more generally.

With the advancement of technologies like in-car navigation and smartphones, concerns around how cognitive functioning is influenced by ¿workload¿ are increasingly prevalent. Research shows that spreading effort across multiple tasks can impair cognitive abilities through an overuse of resources, and that similar overload effects arise in difficult single-task paradigms. We developed a novel lab-based extension of the Detection Response Task, which measures workload, and paired it with a Multiple Object Tracking Task to manipulate cognitive load. Load was manipulated either by changing within-task difficulty or by the addition of an extra task. Using quantitative cognitive modelling we showed that these manipulations cause similar cognitive impairments through diminished processing rates, but that the introduction of a second task tends to invoke more cautious response strategies that do not occur when only difficulty changes. We conclude that more prudence should be exercised when directly comparing multi-tasking and difficulty-based workload impairments, particularly when relying on measures of central tendency.

The usability of the human-machine interface is dependent on the quality of its design and testing. Defining clear criteria that the interface must meet can assist the implementation and evaluation process. These criteria may be based on performance, the quality of users' experience, error prevention, or the broad utility of the interface. In this article, we motivate the use for workload capacity as an empirical measure of usability. We first describe generic and specific uses for workload measures in terms of adaptive interfaces. We then carry out a systematic review of how workload capacity has been empirically measured, based on 172 relevant literature sources from psychology, neuroscience, engineering, and computer science. We then analyse and report on how workload capacity and related constructs, such as perceptual load, attention, and working memory have been defined and measured in these sources. We discuss similarities and differences between constructs and identify opportunities for integrating real-time workload capacity measures into dynamic interfaces.

Objectives: The aim of this study was to investigate the impact of robot-mediated interventions on improvement of social communications and interactions for individuals with autism spectrum disorder. It identified the variables related to social skills that were measured in the reviewed studies. Methods: A systematic review of contemporary peer-reviewed studies published from 2010 to 2019 inclusive was conducted. PsychInfo and Scopus were the databases used to identify the studies. Results: The majority of the reviewed papers demonstrated that the robot-mediated intervention was effective in enhancing social skills in individuals with ASD. Eye contact was the variable most examined to determine the effectiveness of the interventions. Most of the robots were humanoid and operated under a Wizard of Oz autonomous mode and acted predominantly as behavior-eliciting agents. Conclusions: In line with previous studies, robot-mediated interventions were generally effective in improving social skill; however, there was some variability within the individuals with eye contact, joint attention, and imitation being the variables most measured. Areas considered for future research include maintenance and generalization phases with the intervention as well as matching the individuals¿ needs to the features of the robots used.

Objective: Adaptive human behaviour requires cognitive control - the monitoring of actions and performance, to regulate and coordinate ongoing behaviour. Major depression is associated with neuropsychological differences in cognitive control, however behavioural experiments have failed to consistently reflect this. We explore this discrepancy. Method: Two experiments were conducted, in which participants completed an Emotional Stroop task, and the Beck Depression Inventory-II. In Experiment 1, participants were instructed to judge the font colour of a printed word. The word could have emotional or non-emotional meaning. In Experiment 2, participants judged the font colour of the word, and also identified whether any letter was italicised. This manipulation was designed to induce errors to facilitate analysis. Results: Depression symptoms are linked to severe deficits in cognitive control following errors. In Experiment 1, for emotional words, major depression symptoms were associated with a failure to instigate behavioural adjustments following errors, leading to reduced performance (F(1,25) = 4.61, p =.042). For non-emotional content, we found major depression symptoms were associated with substantial adjustments following errors, mitigating reduced performance. These findings were replicated in Experiment 2 using a more robust analysis (F(1,30) = 6.45, p =.017). Conclusions: These findings suggest that under emotional priming, major depression is marked by a failure to adapt behaviour in response to relevant environmental feedback. This work has implications for interpreting prior and future scientific findings, and may also inform clinical applications for depression treatment.

We develop a broad theoretical framework for modelling difficult perceptual information integration tasks under different decision rules. The framework allows us to compare coactive architectures, which combine information before it enters the decision process, with parallel architectures, where logical rules combine independent decisions made about each perceptual source. For both architectures we test the novel hypothesis that participants break the decision rules on some trials, making a response based on only one stimulus even though task instructions require them to consider both. Our models take account of not only the decisions made but also the distribution of the time that it takes to make them, providing an account of speed-accuracy tradeoffs and response biases occurring when one response is required more often than another. We also test a second novel hypothesis, that the nature of the decision rule changes the evidence on which choices are based. We apply the models to data from a perceptual integration task with near threshold stimuli under two different decision rules. The coactive architecture was clearly rejected in favor of logical-rules. The logical-rule models were shown to provide an accurate account of all aspects of the data, but only when they allow for response bias and the possibility for subjects to break those rules. We discuss how our framework can be applied more broadly, and its relationship to Townsend and Nozawa's (1995) Systems-Factorial Technology.

The question of cognitive architecture-how cognitive processes are temporally organized-has arisen in many areas of psychology. This question has proved difficult to answer, with many proposed solutions turning out to be spurious. Systems factorial technology (Townsend & Nozawa, 1995) provided the first rigorous empirical and analytical method of identifying cognitive architecture, using the survivor interaction contrast (SIC) to determine when people are using multiple sources of information in parallel or in series. Although the SIC is based on rigorous nonparametric mathematical modeling of response time distributions, for many years inference about cognitive architecture has relied solely on visual assessment. Houpt and Townsend (2012) recently introduced null hypothesis significance tests, and here we develop both parametric and nonparametric (encompassing prior) Bayesian inference. We show that the Bayesian approaches can have considerable advantages.

Cognitive load from secondary tasks is a source of distraction causing injuries and fatalities on the roadway. The Detection Response Task (DRT) is an international standard for assessing cognitive load on drivers¿ attention that can be performed as a secondary task with little to no measurable effect on the primary driving task. We investigated whether decrements in DRT performance were related to the rate of information processing, levels of response caution, or the non-decision processing of drivers. We had pairs of participants take part in the DRT while performing a simulated driving task, manipulated cognitive load via the conversation between driver and passenger, and observed associated slowing in DRT response time. Fits of the single-bound diffusion model indicated that slowing was mediated by an increase in response caution. We propose the novel hypothesis that, rather than the DRT¿s sensitivity to cognitive load being a direct result of a loss of information processing capacity to other tasks, it is an indirect result of a general tendency to be more cautious when making responses in more demanding situations.

Although post-error slowing and the ¿hot hand¿ (streaks of good performance) are both types of sequential dependencies arising from the differential influence of success and failure, they have not previously been studied together. We bring together these two streams of research in a task where difficulty can be controlled by participants delaying their decisions, and where responses required a degree deliberation, and so are relatively slow. We compared performance of unpaid participants against paid participants who were rewarded differentially, with higher reward for better performance. In contrast to most previous results, we found no post-error slowing for paid or unpaid participants. For the unpaid group, we found post-error speeding and a hot hand, even though the hot hand is typically considered a fallacy. Our results suggest that the effect of success and failure on subsequent performance may differ substantially with task characteristics and demands. We also found payment affected post-error performance; financially rewarding successful performance led to a more cautious approach following errors, whereas unrewarded performance led to recklessness following errors.

While there is widespread agreement among vision researchers on the importance of some local aspects of visual stimuli, such as hue and intensity, there is no general consensus on a full set of basic sources of information used in perceptual tasks or how they are processed. Gestalt theories place particular value on emergent features, which are based on the higher-order relationships among elements of a stimulus rather than local properties. Thus, arbitrating between different accounts of features is an important step in arbitrating between local and Gestalt theories of perception in general. In this paper, we present the capacity coefficient from Systems Factorial Technology (SFT) as a quantitative approach for formalizing and rigorously testing predictions made by local and Gestalt theories of features. As a simple, easily controlled domain for testing this approach, we focus on the local feature of location and the emergent features of Orientation and Proximity in a pair of dots. We introduce a redundant-target change detection task to compare our capacity measure on (1) trials where the configuration of the dots changed along with their location against (2) trials where the amount of local location change was exactly the same, but there was no change in the configuration. Our results, in conjunction with our modeling tools, favor the Gestalt account of emergent features. We conclude by suggesting several candidate information-processing models that incorporate emergent features, which follow from our approach.

In a Stroop task, participants can be presented with a color name printed in color and need to classify the print color while ignoring the word. The Stroop effect is typically calculated as the difference in mean response time (RT) between congruent (e.g., the word RED printed in red) and incongruent (GREEN in red) trials. Delta plots compare not just mean performance, but the entire RT distributions of congruent and incongruent conditions. However, both mean RT and delta plots have some limitations. Arm-reaching trajectories allow a more continuous measure for assessing the time course of the Stroop effect. We compared arm movements to congruent and incongruent stimuli in a standard Stroop task and a control task that encourages processing of each and every word. The Stroop effect emerged over time in the control task, but not in the standard Stroop, suggesting words may be processed differently in the two tasks.

The emotional Stroop effect (ESE) is the result of longer naming latencies to ink colors of emotion words than to ink colors of neutral words. The difference shows that people are affected by the emotional content conveyed by the carrier words even though they are irrelevant to the color-naming task at hand. The ESE has been widely deployed with patient populations, as well as with non-selected populations, because the emotion words can be selected to match the tested pathology. The ESE is a powerful tool, yet it is vulnerable to various threats to its validity. This report refers to potential sources of confounding and includes a modal experiment that provides the means to control for them. The most prevalent threat to the validity of existing ESE studies is sustained effects and habituation wrought about by repeated exposure to emotion stimuli. Consequently, the order of exposure to emotion and neutral stimuli is of utmost importance. We show that in the standard design, only one specific order produces the ESE.

Best practice in understanding and caring for people with advanced Alzheimer's disease presents extraordinary challenges. Their severe and deteriorating cognitive impairments are such that carers find progressive difficulty in authentically ascertaining and responding to interests, preferences, and needs. Deep assessment, a novel multifaceted framework drawn from research into the experiences of others with severe cognitive impairments, has potential to empower carers and other support professionals to develop an enhanced understanding of people with advanced Alzheimer's disease and so deliver better calibrated care in attempts to maximize quality of life. Deep assessment uses a combination of techniques, namely, Behaviour State Observation, Triangulated Proxy Reporting, and Startle Reflex Modulation Measurement, to deliver a comprehensive and deep assessment of the inner states (awareness, preferences, likes, and dislikes) of people who cannot reliably self-report. This paper explains deep assessment and its current applications. It then suggests how it can be applied to people with advanced Alzheimer's disease to develop others' understanding of their inner states and to help improve their quality of life. An illustrative hypothetical vignette is used to amplify this framework. We discuss the potential utility and efficacy of this technique for this population and we also propose other human conditions that may benefit from research using a deep assessment approach.

We examined the role of dual-task interference in working memory using a novel dual two-back task that requires a redundant-target response (i.e., a response that neither the auditory nor the visual stimulus occurred two back versus a response that one or both occurred two back) on every trial. Comparisons with performance on single two-back trials (i.e., with only auditory or only visual stimuli) showed that dual-task demands reduced both speed and accuracy. Our task design enabled a novel application of Townsend and Nozawa¿s (Journal of Mathematical Psychology 39: 321¿359, 1995) workload capacity measure, which revealed that the decrement in dual two-back performance was mediated by the sharing of a limited amount of processing capacity. Relative to most other single and dual n-back tasks, performance measures for our task were more reliable, due to the use of a small stimulus set that induced a high and constant level of proactive interference. For a version of our dual two-back task that minimized response bias, accuracy was also more strongly correlated with complex span than has been found for most other single and dual n-back tasks.

In this paper, we analyze the workload capacity of information processing of multidimensional perceptual stimuli. Capacity, which describes how the processing rate of the system changes as the number of stimulus dimensions or attributes is increased, is an important property of information processing systems. Inferences based on one measure of capacity, the capacity coefficient (Townsend and Nozawa, 1995), are typically computed by comparing the processing of single targets, which provide a measure of the baseline processing time of the system, to the processing of a double target. The single targets are typically assumed to be presented alone without any irrelevant distracting information. In this paper, we derive new capacity predictions for situations when distractor information is present. This extension reveals that, with distractors, the value of the capacity coefficient no longer provides unique diagnostic information about the underlying processing system. We further show how to rectify this situation by contrasting distractors of different discriminability.

This study investigated the link between anxiety and aggression in adolescents with autism spectrum disorders (ASDs) using self-report measures of anxiety and anger and teacher ratings of behaviour. Participants were 104 high school students aged 12-18: 52 students with ASDs, without intellectual disability, and their typically developing peers matched for age and gender. Students with ASDs who attend mainstream high schools reported higher levels of anxiety and reactive anger than their peers, were reported by their teachers to engage in more aggressive behaviours, and were at higher risk of being suspended from school. The results further suggested that social anxiety is a significant moderator of the relationship between autism and physical aggression. For ASD students, but not for the control students, there was a strong, positive relationship: higher levels of anxiety were associated with higher levels of physical aggression. However, ASD students with high anger control did not display physical aggression. Our results have implications for screening students for anxiety, the provision of interventions for managing anxiety and the development of anger management skills, and for the appropriateness of suspension as a mandatory response to incidents of physical aggression in schools.

In the redundant target effect, participants respond faster with two (redundant) targets. We compared the magnitude of this effect in younger and older adults, with and without distractors, in a simple visual-detection task. We employed additional measures that allow non-parametric assessment of performance (Townsend's capacity coefficient) and parametric estimates (Linear Ballistic Accumulator model). Older participants' latencies were slower, especially in the presence of distractors, and their calculated capacity indicators increased with distractors. Parametric estimates indicated that these increases were generated by the older adults' increased difficulty in inhibiting the distractors, and not the results of either improved detection of redundant-targets, or of a generalized slowing of processing.

Identification thresholds and the corresponding efficiencies (ideal/human thresholds) are typically computed by collapsing data across an entire stimulus set within a given task in order to obtain a "multiple-item" summary measure of information use. However, some individual stimuli may be processed more efficiently than others, and such differences are not captured by conventional multiple-item threshold measurements. Here, we develop and present a technique for measuring "single-item" identification efficiencies. The resulting measure describes the ability of the human observer to make use of the information provided by a single stimulus item within the context of the larger set of stimuli. We applied this technique to the identification of 3-D rendered objects (Exp. 1) and Roman alphabet letters (Exp. 2). Our results showed that efficiency can vary markedly across stimuli within a given task, demonstrating that single-item efficiency measures can reveal important information that is lost by conventional multiple-item efficiency measures. © 2013 Psychonomic Society, Inc.

The presence of the Stroop effect betrays the fact that the carrier words were read in the face of instructions to ignore them and to respond to the target ink colors. In this study, we probed the nature of this involuntary reading by comparing color performance with that in a new forced-reading Stroop task in which responding is strictly contingent on reading each and every word. We found larger Stroop effects in the forced-reading task than in the classic Stroop task and concluded that words are processed to a shallower level in the Stroop task than they are in routine voluntary reading. The results show that the two modes of word processing differ in systematic ways and are conductive to qualitatively different representations. These results can pose a challenge to the strongly automatic view of word reading in the Stroop task.

This investigation brings together a response-time system identification methodology (e.g., Townsend & Wenger Psychonomic Bulletin & Review 11, 391¿418, 2004a) and an accuracy methodology, intended to assess models of integration across stimulus dimensions (features, modalities, etc.) that were proposed by Shaw and colleagues (e.g., Mulligan & Shaw Perception & Psychophysics 28, 471¿478, 1980). The goal was to theoretically examine these separate strategies and to apply them conjointly to the same set of participants. The empirical phases were carried out within an extension of an established experimental design called the double factorial paradigm (e.g., Townsend & Nozawa Journal of Mathematical Psychology 39, 321¿359, 1995). That paradigm, based on response times, permits assessments of architecture (parallel vs. serial processing), stopping rule (exhaustive vs. minimum time), and workload capacity, all within the same blocks of trials. The paradigm introduced by Shaw and colleagues uses a statistic formally analogous to that of the double factorial paradigm, but based on accuracy rather than response times. We demonstrate that the accuracy measure cannot discriminate between parallel and serial processing. Nonetheless, the class of models supported by the accuracy data possesses a suitable interpretation within the same set of models supported by the response-time data. The supported model, consistent across individuals, is parallel and has limited capacity, with the participants employing the appropriate stopping rule for the experimental setting.