Matthew S. Cain

Rostral and dorsal anterior cingulate cortex make dissociable contributions during antisaccade error commission

The anterior cingulate cortex (ACC) participates in both performance optimization and evaluation, with dissociable contributions from dorsal (dACC) and rostral (rACC) regions. Deactivation in rACC and other default-mode regions is important for performance optimization, whereas increased rACC and dACC activation contributes to performance evaluation. Errors activate both rACC and dACC. We propose that this activation reflects differential error-related involvement of rACC and dACC during both performance optimization and evaluation, and that these two processes can be distinguished by the timing of their occurrence within a trial. We compared correct and error antisaccade trials. We expected errors to correlate with an early failure of rACC deactivation and increased activation of both rACC and dACC later in the trial. Eighteen healthy subjects performed a series of prosaccade and antisaccade trials during event-related functional MRI. We estimated the hemodynamic responses for error and correct antisaccades using a finite impulse-response model. We examined ACC activity by comparing error and correct antisaccades with a fixation baseline and error to correct antisaccades directly. Compared with correct antisaccades, errors were characterized by an early bilateral failure of deactivation of rACC and other default-mode regions. This difference was significant in rACC. Errors also were associated with increased activity in both rACC and dACC later in the trial. These results show that accurate performance involves deactivation of the rACC and other default mode regions and suggest that both rACC and dACC contribute to the evaluation of error responses.

A Failure of Sleep-Dependent Procedural Learning in Chronic, Medicated Schizophrenia

BACKGROUND Schizophrenia patients have difficulty mastering even rote procedural tasks in rehabilitation settings. Although most studies demonstrate intact procedural learning in schizophrenia, recent findings demonstrate that a critical component of procedural learning is dependent on sleep. This study tested the hypothesis that patients with schizophrenia have a deficit in sleep-dependent procedural learning. METHODS Using a simple, well-characterized test of motor skill learning, the finger tapping motor sequence task (MST), 26 patients with chronic, medicated schizophrenia and 14 demographically matched healthy control subjects were tested on two occasions, 24 hours apart. The main outcome measures were learning of the MST on day 1 (practice-dependent learning) and overnight, sleep-dependent improvement in performance. RESULTS Although schizophrenia patients and control subjects did not differ in practice-dependent learning, patients failed to show overnight improvement (4% deterioration) and differed significantly from control subjects who showed a significant 11% improvement. CONCLUSIONS We present here the first demonstration of a failure of sleep-dependent consolidation of procedural learning in chronic, medicated schizophrenia. This deficit occurred in the context of normal practice-dependent learning within a training session. This behavioral dissociation is consistent with evidence that practice- and sleep-dependent motor learning reflect independent processes and suggests that they are differentially affected in schizophrenia.

Action video game experience reduces the cost of switching tasks

Video game expertise has been shown to have beneficial effects for visual attention processes, but the effects of action video game playing on executive functions, such as task switching and filtering out distracting information, are less well understood. In the main experiment presented here, video game players (VGPs) and nonplayers (nVGPs) switched between two tasks of unequal familiarity: a familiar task of responding in the direction indicated by an arrow, and a novel task of responding in the opposite direction. nVGPs had large response time costs for switching from the novel task to the familiar task, and small costs for switching from the familiar task to the novel task, replicating prior findings. However, as compared to the nVGPs, VGPs were more facile in switching between tasks, producing overall smaller and more symmetric switching costs, suggesting that experience with action video games produces improvements in executive functioning. In contrast, VGPs and nVGPs did not differ in filtering out the irrelevant flanking stimuli or in remembering details of aurally presented stories. The lack of global differences between the groups suggests that the improved task-switching performance seen in VGPs was not due to differences in global factors, such as VGPs being more motivated than nVGPs.

A Bayesian Optimal Foraging Model of Human Visual Search

Real-world visual searches often contain a variable and unknown number of targets. Such searches present difficult metacognitive challenges, as searchers must decide when to stop looking for additional targets, which results in high miss rates in multiple-target searches. In the study reported here, we quantified human strategies in multiple-target search via an ecological optimal foraging model and investigated whether searchers adapt their strategies to complex target-distribution statistics. Separate groups of individuals searched displays with the number of targets per trial sampled from different geometric distributions but with the same overall target prevalence. As predicted by optimal foraging theory, results showed that individuals searched longer when they expected more targets to be present and adjusted their expectations on-line during each search by taking into account the higher-order, across-trial target distributions. However, compared with modeled ideal observers, participants systematically responded as if the target distribution were more uniform than it was, which suggests that training could improve multiple-target search performance.

Distractor Filtering in Media Multitaskers

A growing amount of modern media is consumed simultaneously, a phenomenon known as ‘media multitasking’. Individuals who regularly engage in this activity, heavy media multitaskers (HMMs), are more affected by irrelevant information that can intrude into a primary task than are light media multitaskers (LMMs—Ophir et al, 2009 Proceedings of the National Academy of Sciences of the USA 106 15583). However, the locus of this deficit is unknown, as previous research is consistent with both memory and attentional explanations. Here, we isolated attentional processes by employing a singleton distractor task with low working-memory demands. In this task, LMMs used top – down information to improve their performance, yet HMMs did not. This difference in performance in an established attentional capture task argues for the presence of attentional differences in HMMs and is consistent with the idea that HMMs maintain a wider attentional scope than LMMs, even when instructed otherwise.

Assessing visual search performance differences between Transportation Security Administration Officers and nonprofessional visual searchers

Some visual searches depend upon accuracy (e.g., radiology, airport security screening), and it is important for both theoretical and applied reasons to understand what factors best predict performance. The current study administered a visual search task to both professional (Transportation Security Administration Officers) and nonprofessional (members of Duke University) searchers to examine group differences in which factors predict accuracy. Search speed—time taken to terminate search—was the primary predictor for nonprofessional searchers (accounting for 59% of their accuracy variability) and for the least experienced professional searchers (37% of variability). In contrast, consistency—how similarly (in terms of search speed) an individual spent searching from trial to trial—was the primary predictor for the most experienced professional visual searchers (39% of variability). These results inform cognitive theory by illuminating factors that differentially affect search performance between participants, and real-world issues by identifying search behaviours (consistency in particular) important to experienced professional searchers.

Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory

Action video game playing has been experimentally linked to a number of perceptual and cognitive improvements. These benefits are captured through a wide range of psychometric tasks and have led to the proposition that action video game experience may promote the ability to extract statistical evidence from sensory stimuli. Such an advantage could arise from a number of possible mechanisms: improvements in visual sensitivity, enhancements in the capacity or duration for which information is retained in visual memory, or higher-level strategic use of information for decision making. The present study measured the capacity and time course of visual sensory memory using a partial report performance task as a means to distinguish between these three possible mechanisms. Sensitivity measures and parameter estimates that describe sensory memory capacity and the rate of memory decay were compared between individuals who reported high evels and low levels of action video game experience. Our results revealed a uniform increase in partial report accuracy at all stimulus-to-cue delays for action video game players but no difference in the rate or time course of the memory decay. The present findings suggest that action video game playing may be related to enhancements in the initial sensitivity to visual stimuli, but not to a greater retention of information in iconic memory buffers.

Memory for found targets interferes with subsequent performance in multiple-target visual search

Multiple-target visual searches--when more than 1 target can appear in a given search display--are commonplace in radiology, airport security screening, and the military. Whereas 1 target is often found accurately, additional targets are more likely to be missed in multiple-target searches. To better understand this decrement in 2nd-target detection, here we examined 2 potential forms of interference that can arise from finding a 1st target: interference from the perceptual salience of the 1st target (a now highly relevant distractor in a known location) and interference from a newly created memory representation for the 1st target. Here, we found that removing found targets from the display or making them salient and easily segregated color singletons improved subsequent search accuracy. However, replacing found targets with random distractor items did not improve subsequent search accuracy. Removing and highlighting found targets likely reduced both a targets visual salience and its memory load, whereas replacing a target removed its visual salience but not its representation in memory. Collectively, the current experiments suggest that the working memory load of a found target has a larger effect on subsequent search accuracy than does its perceptual salience.

Anticipatory Anxiety Hinders Detection of a Second Target in Dual-Target Search

Professional visual searches (e.g., baggage screenings, military searches, radiological examinations) are often conducted in high-pressure environments and require focus on multiple visual targets. Yet laboratory studies of visual search tend to be conducted in emotionally neutral settings with only one possible target per display. In the experiment reported here, we looked to better emulate high-pressure search conditions by presenting searchers with arrays that contained between zero and two targets while inducing anticipatory anxiety via a threat-of-shock paradigm. Under conditions of anticipatory anxiety, dual-target performance was negatively affected, but single-target performance and time on task were unaffected. These results suggest that multiple-target searches may be a more sensitive instrument to measure the effect of environmental factors on visual cognition than single-target searches are. Further, the effect of anticipatory anxiety was modulated by individual differences in state anxiety levels of participants prior to the experiment. These results have implications for both the laboratory study of visual search and the management and assessment of professional searchers.

Self-Induced Attentional Blink A Cause of Errors in Multiple-Target Search

Satisfaction of search (which we refer to as subsequent search misses)—a decrease in accuracy at detecting a second target after a first target has been found in a visual search—underlies real-world search errors (e.g., tumors may be missed in an X-ray if another tumor already has been found), but little is known about this phenomenon’s cognitive underpinnings. In the present study, we examined subsequent search misses in terms of another, more extensively studied phenomenon: the attentional blink, a decrease in accuracy when a second target appears 200 to 500 ms after a first target is detected in a temporal stream. Participants searched for T-shaped targets among L-shaped distractors in a spatial visual search, and despite large methodological differences between self-paced spatial visual searches and attentional blink tasks, an attentional-blink-like effect accounted for subsequent-search-miss errors. This finding provides evidence that accuracy is negatively affected shortly after a first target is fixated in a self-paced, self-guided visual search.