Online psychophysics: reaction time effects in cognitive experiments

Using the Internet to acquire behavioral data is currently on the rise. However, very basic questions regarding the feasibility of online psychophysics are still open. Here, we aimed to replicate five well-known paradigms in experimental psychology (Stroop, Flanker, visual search, masked priming, attentional blink) in three settings (classical “lab”, “web-in-lab”, “web”) to account for possible changes in technology and environment. Lab and web-in-lab data were both acquired in an in-lab setting with lab using “Gold Standard” methods, while web-in-lab used web technology. This allowed for a direct comparison of potential differences in acquisition software. To account for additional environmental differences, the web technology experiments were published online to participate from home (setting web), thereby keeping the software and experimental design identical and only changing the environmental setting. Our main results are: First, we found an expected fixed additive timing offset when using web technology (M = 37 ms, SD = 8.14) and recording online (M = 87 ms, SD = 16.04) in comparison to lab data. Second, all task-specific effects were reproduced except for the priming paradigm, which couldn’t be replicated in any setting. Third, there were no differences in error rates, which are independent of the timing offset. This finding further supports the assumption of data equality over all settings. Fourth, we found that browser type might be influencing absolute reaction times. Together, these results contribute to the slowly but steadily growing literature that online psychophysics is a suitable complement – or even substitute – to lab data acquisition.     

调节定向视角下在线评论感知有用性的眼动研究

本研究采用2评论类型(属性型VS体验型)×2调节定向(促进VS预防)的眼动实验,深入探讨消费者对在线评论的加工过程和感知有用性的认知机理。研究发现：(1)与属性型评论相比,个体对体验型评论的认知过程更短,感知有用性却更高。(2)相对于预防定向个体而言,促进定向个体对在线评论的认知加工过程更短,感知有用性更高。(3)评论类型和调节定向的交互效用,在属性型评论情境中显著,但在体验型评论情境中不显著。研究结果揭示了评论类型和调节定向影响消费者对在线评论认知评估的作用机理。     

Oculomotor atypicalities in Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) fail to acquire adequate motor skill, yet surprisingly little is known about the oculomotor system in DCD. Successful completion of motor tasks is supported by accurate visual feedback. The purpose of this study was to determine whether any oculomotor differences can distinguish between children with and without a motor impairment. Using eye tracking technology, visual fixation, smooth pursuit, and pro‐ and anti‐saccade performance were assessed in 77 children that formed three groups: children with DCD (aged 7–10), chronologically age (CA) matched peers, and a motor‐match (MM) group (aged 4–7). Pursuit gain and response preparation in the pro‐ and anti‐saccade tasks were comparable across groups. Compared to age controls, children with DCD had deficits in maintaining engagement in the fixation and pursuit tasks, and made more anti‐saccade errors. The two typically developing groups performed similarly, except on the fast speed smooth pursuit and antisaccade tasks, where the CA group outperformed the younger MM group. The findings suggest that children with DCD have problems with saccadic inhibition and maintaining attention on a visual target. Developmental patterns were evident in the typically developing groups, suggesting that the pursuit system and cognitive control develop with age. This study adds to the literature by being the first to systematically identify specific oculomotor differences between children with and without a motor impairment. Further examination of oculomotor control may help to identify underlying processes contributing to DCD. A video abstract of this article can be viewed at: https://youtu.be/NinXa2KlB4M . [Correction added on 27 January 2017, after first online publication: The video abstract link was added.]     

Using support vector machines to identify literacy skills: Evidence from eye movements

Is inferring readers’ literacy skills possible by analyzing their eye movements during text reading? This study used Support Vector Machines (SVM) to analyze eye movement data from 61 undergraduate students who read a multiple-paragraph, multiple-topic expository text. Forward fixation time, first-pass rereading time, second-pass fixation time, and regression path reading time on different regions of the text were provided as features. The SVM classification algorithm assisted in distinguishing high-literacy-skilled readers from low-literacy-skilled readers with 80.3 % accuracy. Results demonstrate the effectiveness of combining eye tracking and machine learning techniques to detect readers with low literacy skills, and suggest that such approaches can be potentially used in predicting other cognitive abilities.     

Deficits in volitional oculomotor control align with language status in autism spectrum disorders

Eye‐tracking paradigms are increasingly used to investigate higher‐level social and cognitive processing in autism spectrum disorder (ASD). However, the integrity of the oculomotor system within ASD is unclear, with contradictory reports of aberrant eye‐movements on basic oculomotor tasks. The purpose of the current study was to determine whether reducing population heterogeneity and distinguishing neurocognitive phenotypes can clarify discrepancies in oculomotor behaviour evident in previous reports. Reflexive and volitional eye‐movement control was assessed in 73 children aged 8–14 years from four distinct groups: Autism Language Normal (ALN), Autism Language Impaired (ALI), non‐autistic Language Impaired (LI) and Typically Developing (TD). Eye‐movement control was measured using pro‐ and antisaccade tasks and a novel ‘search distracter’ task to measure distractibility. Reflexive eye‐movements were equivalent across groups, but deficits in volitional eye‐movement control were found that aligned with language status, and were not specific to ASD. More than 80% of ALI and LI children presented error rates at least 1.5 SDs below the TD mean in an antisaccade task. In the search distracter task, 35.29% of ALI children and 43.75% of LI children had error rates greater than 1.5 SDs compared with 17.64% of ALN children. A significant proportion of children with neurodevelopmental disorders involving language function have pronounced difficulties suppressing reflexive saccades and maintaining fixations in the presence of competing stimuli. We extend the putative link between ALI and LI populations to non‐language tasks, and highlight the need to account for co‐morbidity in understanding the ontogenesis of ASD.     

Dyslexic and normal readers' eye movements

Dyslexic and normal readers' eye movements were compared while tracking a moving fixation point and in reading. Contrary to previous reports, the dyslexic and normal readers did not differ in their number of saccades, percentage of regressions, or stability of fixations in the tracking task. Thus, defective oculomotor control was not associated with or a causal factor in dyslexia, and the dyslexics' abnormal eye movements in reading must be related to differences in higher cognitive processes. However, individual differences in oculmotor efficiency, independent of reading ability, were found within both the dyslexic and normal groups, and these differences were correlated in reading and tracking tasks.     

Visual tracking in young infants: Evidence for object identity or object permanence?

Previous research has shown that 5-month-old infants visually anticipate a moving object's appearance after it disappears behind a screen. This experiment assesses the underlying basis for such anticipatory tracking. Three tracking tasks were presented to 5- and 9-month-old infants. In the Permanence task, the object's continuous existence was apparently violated while it was behind a screen. In the Feature and Trajectory tasks, the object's features or trajectory changed while behind the screen. Disruptions in the infant's smooth visual pursuit of the object were recorded. Five-mont-olds showed disruptions of visual tracking in the Feature and Trajectory tasks, but not in the Permanence task. The tracking of the 9-month-olds was disrupted in all three tasks. We conclude that both 5- and 9-month-olds possess rules specifying the identity of a moving object which is occluded. For 5-month-olds these rules are based upon the object's features and trajectory, but not upon a concept of object permanence. For 9-month-olds all three rules—feature, trajectory, and permanence—are utilized in visual tracking.     

Pupil diameter measurement errors as a function of gaze direction in corneal reflection eyetrackers

Pupil dilation is a useful, noninvasive technique for measuring the change in cognitive load. Since it is implicit and nonverbal, it is particularly useful with preverbal or nonverbal participants. In cognitive psychology, pupil dilation is most often measured by corneal reflection eye-tracking devices. The present study investigates the effect of gaze position on pupil size estimation by three common eye-tracking systems. The task consisted of a simple object pursuit situation, as a sphere rotated around the display screen. Systematic errors of pupil size estimation were found with all three systems. Implications for task-elicited pupillometry, especially for gaze-contingent studies such as object tracking or reading, are discussed.     

Human classifier: Observers can deduce task solely from eye movements

Computer classifiers have been successful at classifying various tasks using eye movement statistics. However, the question of human classification of task from eye movements has rarely been studied. Across two experiments, we examined whether humans could classify task based solely on the eye movements of other individuals. In Experiment 1, human classifiers were shown one of three sets of eye movements: Fixations, which were displayed as blue circles, with larger circles meaning longer fixation durations; Scanpaths, which were displayed as yellow arrows; and Videos, in which a neon green dot moved around the screen. There was an additional Scene manipulation in which eye movement properties were displayed either on the original scene where the task (Search, Memory, or Rating) was performed or on a black background in which no scene information was available. Experiment 2 used similar methods but only displayed Fixations and Videos with the same Scene manipulation. The results of both experiments showed successful classification of Search. Interestingly, Search was best classified in the absence of the original scene, particularly in the Fixation condition. Memory also was classified above chance with the strongest classification occurring with Videos in the presence of the scene. Additional analyses on the pattern of correct responses in these two conditions demonstrated which eye movement properties successful classifiers were using. These findings demonstrate conditions under which humans can extract information from eye movement characteristics in addition to providing insight into the relative success/failure of previous computer classifiers.     

Glance analysis of driver eye movements to evaluate distraction

With the increasing use of in-vehicle devices in cars, an understanding of the safety implications of secondary tasks has become crucial. It is now possible to study the effects of many in-vehicle devices and tasks on driving by using head-mounted eye-tracking devices (HEDs) to collect eye positions and pupil diameters, which have been considered indicators of attentional focus. The collection of eye-position and pupil-diameter data of automobile drivers under on-road conditions and while completing various secondary tasks is described in this paper. Drivers were asked to drive on a preselected two-lane road for a total distance of 22 miles while gaze data were recorded using a HED. Longer off-road fixation durations were observed in radio-tuning and rearview mirror checking tasks, but not in the odometer checking task. In addition, the standard deviations of fixation displacements during a cognitive task involving the computation of a date for a meeting were shorter than those observed during normal driving.     

Novel Measures of Response Performance and Inhibition in Children with ADHD

Fifteen children with ADHD aged 8 to 12 years and age and gender matched controls performed two different stopping tasks to examine response performance and inhibition and their respective moment-to-moment variability. One task was the well-established stop-signal task, while the other was a novel tracking task where the children tracked a spaceship on the screen until an alarm indicated they should stop. Although performance was discrete in the stop signal task and continuous in the tracking task, in both tasks latencies to the stop signal were significantly slowed in children with ADHD. Go performance and variability did not significantly differ between ADHD and control children in either task. Importantly, stopping latency in the novel spaceship tracking task also was more variable in children with ADHD. As stopping variability cannot be measured using the standard stop signal task, the new task offers compelling support for the heretofore untested prediction that stopping is both slowed and more variable in children with ADHD. The results support a response inhibition impairment in ADHD, whilst limiting the extent of an intra-trial variability deficit.

Towards testing auditory–vocal interfaces and detecting distraction while driving: A comparison of eye-movement measures in the assessment of cognitive workload

Recently, there has been a growing need among researchers to understand the problem of cognitive workload induced by auditory–verbal–vocal tasks while driving in realistic conditions. This is due to the fact that we need (a) valid methods to evaluate in-vehicle electronic devices using voice control systems and (b) experimental data to build more reliable driver state monitoring systems. In this study, we examined the effects of cognitive workload induced by the delayed digit recall task (n-back) while driving. We used a high-fidelity driving simulator and a highway scenario with moderate traffic to study eye movements in realistic driving conditions. This study included 46 participants, and the results indicate that a change in pupil size is most sensitive for measuring changes in cognitive demand in auditory–verbal–vocal tasks. Less sensitive measures included changes in fixation location and blink rate. Fixation durations and the driving performance metrics did not provide sensitive measures of graded levels of cognitive demand.     

Eye movements disrupt spatial but not visual mental imagery

It has long been known that eye movements are functionally involved in the generation and maintenance of mental images. Indeed, a number of studies demonstrated that voluntary eye movements interfere with mental imagery tasks (e.g., Laeng and Teodorescu in Cogn Sci 26:207–231, 2002). However, mental imagery is conceived as a multifarious cognitive function with at least two components, a spatial component and a visual component. The present study investigated the question of whether eye movements disrupt mental imagery in general or only its spatial component. We present data on healthy young adults, who performed visual and spatial imagery tasks concurrently with a smooth pursuit. In line with previous literature, results revealed that eye movements had a strong disruptive effect on spatial imagery. Moreover, we crucially demonstrated that eye movements had no disruptive effect when participants visualized the depictive aspects of an object. Therefore, we suggest that eye movements serve to a greater extent the spatial than the visual component of mental imagery.     

Validation of a Behavioral Approach for Measuring Saccades in Parkinson's Disease

Speed and control of saccades are related to disease progression and cognitive functioning in Parkinson's disease (PD). Traditional eye-tracking complexities encumber application for individual evaluations and clinical trials. The authors examined psychometric properties of standalone tasks for reflexive prosaccade latency, volitional saccade initiation, and saccade inhibition (antisaccade) in a heterogeneous sample of 65 PD patients. Demographics had minimal impact on task performance. Thirty-day test–retest reliability estimates for behavioral tasks were acceptable and similar to traditional eye tracking. Behavioral tasks demonstrated concurrent validity with traditional eye-tracking measures; discriminant validity was less clear. Saccade initiation and inhibition discriminated PD patients with cognitive impairment. The present findings support further development and use of the behavioral tasks for assessing latency and control of saccades in PD.     

Catching a glimpse of working memory: top-down capture as a tool for measuring the content of the mind

This article outlines a methodology for probing working memory (WM) content in high-level cognitive tasks (e.g., decision making, problem solving, and memory retrieval) by capitalizing on attentional and oculomotor biases evidenced in top-down capture paradigms. This method would be of great use, as it could measure the information resident in WM at any point in a task and, hence, track information use over time as tasks dynamically evolve. Above and beyond providing a measure of information occupancy in WM, such a method would benefit from sensitivity to the specific activation levels of individual items in WM. This article additionally forwards a novel fusion of standard free recall and visual search paradigms in an effort to assess the sensitivity of eye movements in top-down capture, on which this new measurement technique relies, to item-specific memory activation (ISMA). The results demonstrate eye movement sensitivity to ISMA in some, but not all, cases.     

Attention during visual secondary tasks in driving: Adaptation to the demands of the driving task

Visual attention in driving with visual secondary task is compared for two visual secondary tasks. N = 40 subjects completed a 1 h test drive in a motion-base driving simulator. During the drive, participants either solved an externally paced, highly demanding visual task or a self paced menu system task. The secondary tasks were offered in defined critical and non-critical driving situations. Eye movement behavior was analyzed and compared for both tasks. Before starting the secondary tasks, eye movement behavior shows a smaller standard deviation of gaze as well as longer fixation durations for both tasks. The comparison between the two tasks indicates that drivers use the possibilities the self paced task offers: during the secondary task, they monitor the driving scene with longer fixations and show a greater standard deviation of gaze position. Furthermore, independently of the type of secondary task, drivers adapt their eye movement behavior to the demands of the situation. In critical driving situations they direct a larger proportion of glance time to the driving task. Last, the relation between glance behavior and collisions is analyzed. Results indicate that collisions go together with an inadequate distribution of attention during distraction. The results are interpreted regarding the attentional processes involved in driving with visual secondary tasks. Based on the similarities and differences between the two secondary tasks, a cognitive approach is developed which assumes that the control of attention during distraction is based on a mental situational model of the driving situation.     

执行意向影响事件性前瞻记忆的加工机制

本研究旨在探究不同执行意向编码形式对前瞻记忆加工机制的影响是否存在差异。结果显示在低认知负荷下,混合编码效果最好,仅执行意向编码次之,标准编码效果最差,而在高认知负荷下三种编码效果无差异。眼动指标显示在低认知负荷下混合编码的注视点数量最多,总注视时间最长;在混合编码条件下进行中任务和前瞻记忆任务的总注视时间均长于仅执行意向编码和标准编码。结果说明,执行意向编码容易受认知负荷的影响;在低认知负荷下混合编码的被试对任务刺激进行更多的监控和加工,而仅执行意向编码促进前瞻记忆任务的自动化加工。     

Temporal characteristics of overt attentional behavior during category learning

Many theories of category learning incorporate mechanisms for selective attention, typically implemented as attention weights that change on a trial-by-trial basis. This is because there is relatively little data on within-trial changes in attention. We used eye tracking and mouse tracking as fine-grained measures of attention in three complex visual categorization tasks to investigate temporal patterns in overt attentional behavior within individual categorization decisions. In Experiments 1 and 2, we recorded participants’ eye movements while they performed three different categorization tasks. We extended previous research by demonstrating that not only are participants less likely to fixate irrelevant features, but also, when they do, these fixations are shorter than fixations to relevant features. We also found that participants’ fixation patterns show increasingly consistent temporal patterns. Participants were faster, although no more accurate, when their fixation sequences followed a consistent temporal structure. In Experiment 3, we replicated these findings in a task where participants used mouse movements to uncover features. Overall, we showed that there are important temporal regularities in information sampling during category learning that cannot be accounted for by existing models. These can be used to supplement extant models for richer predictions of how information is attended to during the buildup to a categorization decision.