The future of simulation-based medical education: Adaptive simulation utilizing a deep multitask neural network.

BACKGROUND: In resuscitation medicine, effectively managing cognitive load in high-stakes environments has important implications for education and expertise development. There exists the potential to tailor educational experiences to an individual's cognitive processes via real-time physiologic measurement of cognitive load in simulation environments. OBJECTIVE: The goal of this research was to test a novel simulation platform that utilized artificial intelligence to deliver a medical simulation that was adaptable to a participant's measured cognitive load. METHODS: The research was conducted in 2019. Two board-certified emergency physicians and two medical students participated in a 10-minute pilot trial of a novel simulation platform. The system utilized artificial intelligence algorithms to measure cognitive load in real time via electrocardiography and galvanic skin response. In turn, modulation of simulation difficulty, determined by a participant's cognitive load, was facilitated through symptom severity changes of an augmented reality (AR) patient. A postsimulation survey assessed the participants' experience. RESULTS: Participants completed a simulation that successfully measured cognitive load in real time through physiological signals. The simulation difficulty was adapted to the participant's cognitive load, which was reflected in changes in the AR patient's symptoms. Participants found the novel adaptive simulation platform to be valuable in supporting their learning. CONCLUSION: Our research team created a simulation platform that adapts to a participant's cognitive load in real-time. The ability to customize a medical simulation to a participant's cognitive state has potential implications for the development of expertise in resuscitation medicine.

Remembering more than you can say: Re-examining "amnesia" of attended attributes.

Attribute amnesia (AA) describes a phenomenon whereby observers fail a surprise memory test which asks them to report an attribute they had just attended and used to fulfil a task goal. This finding has cast doubt on the prominent theory that attention results in encoding into working memory (WM), to which two competing explanations have been proposed: (1) task demands dictate whether attended information is encoded into WM, and (2) attended information is encoded in a weak state that does not survive the demands of the surprise memory test. To address this debate our study circumvented the limitations of a surprise memory test by embedding a second search task within a typical color-based AA search task. The search task was modified so that the attended attribute would reappear in the second search as either the target, a distractor, or not at all. Critically, our results support encoding of the attended attribute in WM though to a weaker extent than the attribute that is required for report. A second experiment confirmed that WM encoding only occurs for the attended attribute, though distractor attributes produce a bias consistent with negative priming. Our data provide novel support for a theory of memory consolidation that links the strength of a memory's representation with expectations for how it will be used in a task. Implications for the utility of this procedure in future investigations previously limited by single trial data (i.e., surprise question methodology) are discussed.

In support of selective rehearsal: Double-item presentation in item-method directed forgetting.

Despite the substantial evidence highlighting the role of selective rehearsal in item-method directed forgetting, recent work has suggested that forgetting may occur as a function of an active inhibitory mechanism that is more effortful than elaborative rehearsal processes. In the present work, we test this hypothesis by implementing a double-item presentation within the item-method directed forgetting paradigm. Participants studied two unrelated items at a time. Some words were followed by the same cue, and participants were instructed to remember or forget both items (pure condition). On other trials, participants were to remember one but forget the other word (mixed condition). Selective rehearsal and inhibition accounts make distinct predictions regarding memory performance in the double-item presentation. In Experiment 1, we compared recognition performance in the pure and mixed conditions, while in Experiment 2, we included a neutral baseline condition to further distinguish between the selective rehearsal and inhibition accounts. Contrary to the inhibition account but consistent with selective rehearsal, we found for both remember and forget items that recognition was greater in the mixed than in the pure condition. Recognition for forget items also did not differ from neutral items. We conclude that selective rehearsal, not inhibition, is responsible for item-method directed forgetting.

The price of information: Increased inspection costs reduce the confirmation bias in visual search.

In visual search, there is a confirmation bias such that attention is biased towards stimuli that match a target template, which has been attributed to covert costs of updating the templates that guide search [Rajsic, Wilson, & Pratt, 2015. Confirmation bias in visual search. Journal of Experimental Psychology: Human Perception and Performance. Advance online publication. doi:10.1037/xhp0000090]. In order to provide direct evidence for this speculation, the present study increased the cost of inspections in search by using gaze- and mouse-contingent searches, which restrict the manner in which information in search displays can be accrued, and incur additional motor costs (in the case of mouse-contingent searches). In a fourth experiment, we rhythmically mask elements in the search display to induce temporal inspection costs. Our results indicated that confirmation bias is indeed attenuated when inspection costs are increased. We conclude that confirmation bias results from the low-cost strategy of matching information to a single, concrete visual template, and that more sophisticated guidance strategies will be used when sufficiently beneficial. This demonstrates that search guidance itself comes at a cost, and that the form of guidance adopted in a given search depends on a comparison between guidance costs and the expected benefits of their implementation.

Temporal trimming: Evidence that common-onset masking shortens perceptual sampling of conscious object representations.

Common-onset masking (COM) refers to a methodology where a mask can impair awareness of an object if the mask's offset is delayed relative to the offset of the object. This method has classically been used to understand how discontinuities in visual input lead to the discrete removal of object representations before they reach conscious awareness. However, COM has recently been shown to reduce the precision of conscious object representations (Harrison, Rajsic, & Wilson, Psychonomic Bulletin & Review, 23(1), 180-186, 2016). As a result, Harrison et al. proposed that COM shortens the temporal window for perceptual sampling of an object's representation, an account consistent with interruption-based theories of masking. In the present study we modified the standard COM methodology to assess the impact of a delayed mask offset on the temporal perception of an object's representation. Across two experiments we provide novel evidence that a delayed mask offset can impair temporal perception of a conscious percept, such that it reduces the percept's perceived duration (Experiment 1), and prematurely terminates updating of the percept's dynamic orientation (Experiment 2). We refer to these results as temporal trimming, and suggest that the mechanism responsible for COM operates during the sustained perception of an object.

Looking sharp: Becoming a search template boosts precision and stability in visual working memory.

Visual working memory (VWM) plays a central role in visual cognition, and current work suggests that there is a special state in VWM for items that are the goal of visual searches. However, whether the quality of memory for target templates differs from memory for other items in VWM is currently unknown. In this study, we measured the precision and stability of memory for search templates and accessory items to determine whether search templates receive representational priority in VWM. Memory for search templates exhibited increased precision and probability of recall, whereas accessory items were remembered less often. Additionally, while memory for Templates showed benefits when instances of the Template appeared in search, this benefit was not consistently observed for Accessory items when they appeared in search. Our results show that becoming a search template can substantially affect the quality of a representation in VWM.

Accessibility limits recall from visual working memory.

In this article, we demonstrate limitations of accessibility of information in visual working memory (VWM). Recently, cued-recall has been used to estimate the fidelity of information in VWM, where the feature of a cued object is reproduced from memory (Bays, Catalao, & Husain, 2009; Wilken & Ma, 2004; Zhang & Luck, 2008). Response error in these tasks has been largely studied with respect to failures of encoding and maintenance; however, the retrieval operations used in these tasks remain poorly understood. By varying the number and type of object features provided as a cue in a visual delayed-estimation paradigm, we directly assess the nature of retrieval errors in delayed estimation from VWM. Our results demonstrate that providing additional object features in a single cue reliably improves recall, largely by reducing swap, or misbinding, responses. In addition, performance simulations using the binding pool model (Swan & Wyble, 2014) were able to mimic this pattern of performance across a large span of parameter combinations, demonstrating that the binding pool provides a possible mechanism underlying this pattern of results that is not merely a symptom of one particular parametrization. We conclude that accessing visual working memory is a noisy process, and can lead to errors over and above those of encoding and maintenance limitations. (PsycINFO Database Record

Object-substitution masking degrades the quality of conscious object representations.

Object-substitution masking (OSM) is a unique paradigm for the examination of object updating processes. However, existing models of OSM are underspecified with respect to the impact of object updating on the quality of target representations. Using two paradigms of OSM combined with a mixture model analysis we examine the impact of post-perceptual processes on a target's representational quality within conscious awareness. We conclude that object updating processes responsible for OSM cause degradation in the precision of object representations. These findings contribute to a growing body of research advocating for the application of mixture model analysis to the study of how cognitive processes impact the quality (i.e., precision) of object representations.

Confirmation bias in visual search.

In a series of experiments, we investigated the ubiquity of confirmation bias in cognition by measuring whether visual selection is prioritized for information that would confirm a proposition about a visual display. We show that attention is preferentially deployed to stimuli matching a target template, even when alternate strategies would reduce the number of searches necessary. We argue that this effect is an involuntary consequence of goal-directed processing, and show that it can be reduced when ample time is provided to prepare for search. These results support the notion that capacity-limited cognitive processes contribute to the biased selection of information that characterizes confirmation bias. (PsycINFO Database Record

Self-perception of competencies in adolescents with autism spectrum disorders.

Research has demonstrated that, despite difficulties in multiple domains, children with autism spectrum disorders (ASD) show a lack of awareness of these difficulties. A misunderstanding of poor competencies may make it difficult for individuals to adjust their behaviour in accordance with feedback and may lead to greater impairments over time. This study examined self-perceptions of adolescents with ASD (n = 19) and typically developing (TD) mental-age-matched controls (n = 22) using actual performance on objective academic tasks as the basis for ratings. Before completing the tasks, participants were asked how well they thought they would do (pre-task prediction). After completing each task, they were asked how well they thought they did (immediate post-performance) and how well they would do in the future (hypothetical future post-performance). Adolescents with ASD had more positively biased self-perceptions of competence than TD controls. The ASD group tended to overestimate their performance on all ratings of self-perceptions (pre-task prediction, immediate, and hypothetical future post-performance). In contrast, while the TD group was quite accurate at estimating their performance immediately before and after performing the task, they showed some tendency to overestimate their future performance. Future investigation is needed to systematically examine possible mechanisms that may be contributing to these biased self-perceptions.

Asymmetrical access to color and location in visual working memory.

Models of visual working memory (VWM) have benefitted greatly from the use of the delayed-matching paradigm. However, in this task, the ability to recall a probed feature is confounded with the ability to maintain the proper binding between the feature that is to be reported and the feature (typically location) that is used to cue a particular item for report. Given that location is typically used as a cue-feature, we used the delayed-estimation paradigm to compare memory for location to memory for color, rotating which feature was used as a cue and which was reported. Our results revealed several novel findings: 1) the likelihood of reporting a probed object's feature was superior when reporting location with a color cue than when reporting color with a location cue; 2) location report errors were composed entirely of swap errors, with little to no random location reports; and 3) both colour and location reports greatly benefitted from the presence of nonprobed items at test. This last finding suggests that it is uncertainty over the bindings between locations and colors at memory retrieval that drive swap errors, not at encoding. We interpret our findings as consistent with a representational architecture that nests remembered object features within remembered locations.

Long-term facilitation of return: a response-retrieval effect.

The present study used a target-target procedure to examine the extent to which perceptual and response factors contribute to inhibition of return (IOR) in a visual discrimination task. When the target was perceptually identical to the previous target and the required response was the same, facilitation was observed for both standard and long-term target-target stimulus onset asynchronies (SOAs). When the color of the previous target differed from that of the current target but the response remained the same, facilitation was reduced in both the standard SOA and long-term SOA conditions. Finally, IOR was observed for both standard and long-term SOAs only in the condition in which there was a change in response. This pattern of inhibition and facilitation provides new evidence that the responses previously associated with a location play an important role in the ability to respond to a stimulus. We interpret this finding as consistent with a framework in which the involuntary retrieval of bound stimulus-response episodes contributes to response compatibility effects in visual stimulus discrimination.

Effortful listening: the processing of degraded speech depends critically on attention.

The conditions of everyday life are such that people often hear speech that has been degraded (e.g., by background noise or electronic transmission) or when they are distracted by other tasks. However, it remains unclear what role attention plays in processing speech that is difficult to understand. In the current study, we used functional magnetic resonance imaging to assess the degree to which spoken sentences were processed under distraction, and whether this depended on the acoustic quality (intelligibility) of the speech. On every trial, adult human participants attended to one of three simultaneously presented stimuli: a sentence (at one of four acoustic clarity levels), an auditory distracter, or a visual distracter. A postscan recognition test showed that clear speech was processed even when not attended, but that attention greatly enhanced the processing of degraded speech. Furthermore, speech-sensitive cortex could be parcellated according to how speech-evoked responses were modulated by attention. Responses in auditory cortex and areas along the superior temporal sulcus (STS) took the same form regardless of attention, although responses to distorted speech in portions of both posterior and anterior STS were enhanced under directed attention. In contrast, frontal regions, including left inferior frontal gyrus, were only engaged when listeners were attending to speech and these regions exhibited elevated responses to degraded, compared with clear, speech. We suggest this response is a neural marker of effortful listening. Together, our results suggest that attention enhances the processing of degraded speech by engaging higher-order mechanisms that modulate perceptual auditory processing.

Dilution, not load, affects distractor processing.

Lavie and Tsal (1994) proposed that spare attentional capacity is allocated involuntarily to the processing of irrelevant stimuli, thereby enabling interference. Under this view, when task demands increase, spare capacity should decrease and distractor interference should decrease. In support, Lavie and Cox (1997) found that increasing perceptual load by increasing search set size decreased interference from an irrelevant distractor. In three experiments, we manipulated the cue set size (number of cued locations) independently of the display set size (number of letters presented). Increasing the display set size reduced distractor interference regardless of whether the additional letters were relevant to the task. In contrast, increasing the cue set size increased distractor interference. Both findings are inconsistent with the load explanation, but are consistent with a proposed two-stage dilution account.

Control of spatial and feature-based attention in frontoparietal cortex.

Visual attention selects task-relevant information from scenes to help achieve behavioral goals. Attention can be deployed within multiple domains to select specific spatial locations, features, or objects. Recent evidence has shown that voluntary shifts of attention in multiple domains are consistently associated with transient increases in cortical activity in medial superior parietal lobule, suggesting that this may be the source of a domain-independent control signal that initiates the reconfiguration of attention. To investigate this hypothesis, we used fMRI to measure changes in cortical activation while human subjects shifted attention between spatial locations or between colors at a location. Univariate multiple regression analysis revealed a common, domain-independent transient signal [in posterior parietal cortex (PPC) and prefrontal cortex] time-locked to shifts of attention in both domains. However, multivariate pattern classification conducted on the cortical surface revealed that the spatiotemporal pattern of activity within PPC differed reliably for spatial and feature-based attention shifts. These results suggest that the posterior parietal cortex is a common hub for the control of attention shifts but contains subpopulations of neurons with domain-specific tuning for cognitive control.

Turning the process-dissociation procedure inside-out: a new technique for understanding the relation between conscious and unconscious influences.

While there is now general agreement that memory gives rise to both conscious and unconscious influences, there remains disagreement concerning the process architecture underlying these distinct influences. Do they arise from independent underlying systems (e.g., Jacoby, 1991) or from systems that are interactive (e.g., Joordens & Merikle, 1993)? In the current paper we present a novel "inside-out" technique that can be used with the process-dissociation paradigm to arrive at more concrete conclusions concerning this central question and demonstrate this technique via a meta-analysis of currently published findings. Our results suggest that the data presented in these studies vary in ways most consistent with the assumption that conscious and unconscious influences behave independently.

Practice in visual search produces decreased capacity demands but increased distraction.

Lavie (1995) proposed a load account of selective attention, which holds that spare capacity is involuntarily allocated to the processing of irrelevant stimuli. In support of this account, Lavie and Cox (1997) combined a letter search task with a flanker task and found that increasing load (search set size) resulted in decreased interference from an irrelevant distractor letter. In three experiments using a very similar procedure, we varied distractor location and distractor distinctiveness and observed that as load increased (from set size 2 to set size 6), there was a consistent reduction in interference. Critically, we addressed a fundamental hypothesis derived from the load account-that practice reduces capacity demands. This hypothesis leads to the rather counterintuitive prediction that as performance improves with practice, distractor processing should actually increase. Indeed, we found that interference in a high-load condition (set size 6), but not in a low-load condition (set size 2), did increase with practice. We describe a two-stage dilution account of attention that accommodates these results.

Synchrony effects in automatic and controlled retrieval.

Using a speeded retrieval procedure, we investigated time-of-day effects in automatic and controlled retrieval. Morning-type adults were tested at either peak (early morning) or off-peak (late afternoon) times on a speeded implicit (Experiment 1) or explicit (Experiment 2) stem completion task. In Experiment 1, retrieval strategies were identified by changes in response speed between a practice phase with rapid retrieval and an implicit memory test phase. Performance based on controlled retrieval (shown by slowdown participants) showed more priming at peak than at off-peak times of day, a finding confirmed in Experiment 2, in which the participants were given intentional retrieval instructions when the materials switched. In contrast, performance based on automatic retrieval (shown by nonslowdown participants) did not differ across peak and off-peak times. The finding suggests a robust synchrony effect in controlled retrieval, but not in automatic retrieval, which does not appear to vary across the day.

Evidence from a response choice task reveals a selection bias in the attentional cueing paradigm.

In a typical attentional cueing paradigm, irrelevant peripheral cues produce early facilitation (fast responses) followed by later inhibition (slow responses) to cued locations. Here we examine whether cues not only influence the speed with which responses are produced, but also impact or bias which location is ultimately selected as requiring a response. Specifically, can cues influence not only the speed with which we respond but also influence the behavior produced? To examine this question, a choice localization task was used in which no targets were presented, and subjects were asked to choose which effector (left hand, right hand) to use in response to a centrally presented tone. Thus, following either a left or right peripheral cue, and then a central tone, subjects were free to respond with either their left or right hand. Early facilitation and later inhibition with this choice procedure were found in both response times and the proportion of responses to the cued and uncued locations. These results suggest that there are processes which initially bias response selection toward cued locations and then subsequently bias response selection away from cued locations.

Long-term inhibition of return for spatial locations: evidence for a memory retrieval account.

It has generally been accepted that attention is inhibited from returning to previously attended locations, and that this inhibition of return (IOR) lasts just two or three seconds. Recently, Tipper, Grison, and Kessler (2003) showed that IOR can occur over much longer periods of time provided the inhibition is encoded with a context-rich event. Here we examine standard (i.e., typical time range) and long-term IOR within the same experimental paradigm as a means to compare their properties. Experiment 1 used the simple displays typical of cueing paradigms and revealed that both standard and long-term IOR can be obtained under such conditions. Experiment 2 showed that both standard and long-term IOR occurred when there was incongruence between the required response on the current trial and that stored in memory. Furthermore, IOR was not produced when there was incongruence between a target feature (colour) of the current trial and that stored in memory. These results are consistent with a memory retrieval account of IOR and suggest that the same inhibitory mechanism may underlie both standard and long-term IOR.