Elise F. Darling

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.

Links between multisensory processing and autism

Autism spectrum disorder is typically associated with social deficits and is often specifically linked to difficulty with processing faces and other socially relevant stimuli. Emerging research has suggested that children with autism might also have deficits in basic perceptual abilities including multisensory processing (e.g., simultaneously processing visual and auditory inputs). The current study examined the relationship between multisensory temporal processing (assessed via a simultaneity judgment task wherein participants were to report whether a visual stimulus and an auditory stimulus occurred at the same time or at different times) and self-reported symptoms of autism (assessed via the Autism Spectrum Quotient questionnaire). Data from over 100 healthy adults revealed a relationship between these two factors as multisensory timing perception correlated with symptoms of autism. Specifically, a stronger bias to perceive auditory stimuli occurring before visual stimuli as simultaneous was associated with greater levels of autistic symptoms. Additional data and analyses confirm that this relationship is specific to multisensory processing and symptoms of autism. These results provide insight into the nature of multisensory processing while also revealing a continuum over which perceptual abilities correlate with symptoms of autism and that this continuum is not just specific to clinical populations but is present within the general population.

Visual search at the airport: Testing TSA officers

A significant challenge for laboratory-based research is to adequately replicate conditions found in the real world. Likewise, a challenge for field-based research is to appropriately maintain the precision and control found within the laboratory. These hurdles are easily noticed when studying visual search, the act of finding a target amongst distractors. Decades of laboratory-based research have revealed many factors affecting visual search (see Nakayama & Martini, 2011 for a recent review); yet, these ‘sterile’ tasks conducted with novice participants can at times bear little resemblance to the tasks of professional searchers such as baggage screeners, radiologists, lifeguards, and military personnel. Conversely, conducting research with expert searchers in their natural environment can be logistically complex, which limits the scope of questions that can be asked. We are bridging this gap by conducting laboratory-based research with professional, expert searchers: employed Transportation Security Administration (TSA) officers at Raleigh-Durham International Airport. We have established a cognitive psychology laboratory within the airport, and the TSA officers participate in our research studies during their normal work hours. We are assessing a variety of visual and attentional abilities, including several measures of visual search. For example, in one task we employed a simplified visual search experiment to directly compare novice searchers (Duke University undergraduates) to expert searchers (TSA officers). Participants looked for ‘T’s amongst ‘L’s with set sizes of 8, 16, 24, and 32. Compared to undergraduates, TSA officers were slower to respond, with search slopes approximately 1.5 times larger. Importantly, the TSA agents were also more accurate at each set size, suggesting a greater search diligence. Through tasks such as these, combined with measures of individual differences (e.g., personality and clinical assessments), the goal of this project is to inform both cognitive theories of visual search and the TSA’s standard operating procedures.

Visual Expertise: Insights Gained by Comparing Professional Populations

Professionals whose careers depend on visual skills typically demonstrate superior performance on career-related tasks; farmers better determine the sex of day-old chicks (Biederman & Shiffrar, 1987), and bank tellers better detect counterfeit currency (Klein, Gadbois, & Christie, 2004). Perceptual expertise has implications for learning and malleability, but the interpretation of expertise benefits is not straightforward. Complications arise, in part, because standard methodologies typically compare professionals to laypersons, raising concerns about confounding differences (e.g., motivation, speed/accuracy tradeoff, self-selection). Additionally, the mechanisms responsible for improvement may be ambiguous (e.g., enhanced sensory discrimination vs. improved strategies). To account for these issues, we analyzed performance across different professional groups on tasks related and unrelated to their careers. We assessed two groups of visual search experts (radiologists, airport security screeners), one group of facial symmetry experts (orthodontists), and one non-professional group (university participants). As expected, the professional groups demonstrated superior accuracy for career-related tasks (radiologists and airport security screeners for search, orthodontists for facial symmetry), and additional comparisons provided further insight. To evaluate potential differences in motivation, we compared performance on a task unrelated to the professionals’ expertise—temporal order judgment—and found no accuracy differences between professionals and non-professionals. Relatedly, comparisons between professional groups minimized speed/accuracy tradeoff concerns; professionals were slower on all tasks but only showed enhanced accuracy for career-relevant tasks. To elucidate whether benefits arose from self-selection or experience, we compared early- versus late-career individuals within the same profession and found differences related to amount of experience. Finally, we explored the nature of experts’ improvements and found evidence supporting superior top-down strategy selection (search professionals choose more effective strategies) as well as bottom-up stimulus-specific processing (orthodontists revealed enhanced symmetry discrimination for faces only). By comparing different types of experts on multiple tasks, we can better inform the nature of visual expertise.