Visual expertise is more than meets the eye: an examination of holistic visual processing in radiologists and architects.

Purpose: One of the dominant behavioral markers of visual-expert search strategy, holistic visual processing (HVP), suggests that experts process information from a larger region of space in conjunction with a more focused gaze pattern to improve search speed and accuracy. To date, extant literature suggests that visual search expertise is domain specific, including HVP and its associated behaviors. Approach: The current study is the first to use eye tracking to directly measure the HVP strategies of two expert groups, radiologists and architects, in comparison to one another and a novice control. Results: In doing so, we replicated and extended this prior research: visual expertise is domain specific. However, our eye-tracking data indicate that contrary to this prior work, HVP strategies are transferable across domains. Yet, despite the transfer of HVP strategies, there is neither reduced search time nor greater accuracy in visual search outside of an expert's domain. Conclusions: Therefore, our data suggest that HVP behaviors are a particular form of visual search mechanism that, outside of an expert's native search-ecology, are not necessarily conducive to more general visual search success. It is in addition to explicit knowledge of an expert's domain, how to search, and where to search, that HVP strategies are their most effective for visual search success.

Through the eyes of the expert: Evaluating holistic processing in architects through gaze-contingent viewing.

Studies in the psychology of visual expertise have tended to focus on a limited set of expert domains, such as radiology and athletics. Conclusions drawn from these data indicate that experts use parafoveal vision to process images holistically. In this study, we examined a novel, as-of-yet-unstudied class of visual experts-architects-expecting similar results. However, the results indicate that architects, though visual experts, may not employ the holistic processing strategy observed in their previously studied counterparts. Participants (n = 48, 24 architects, 24 naïve) were asked to find targets in chest radiographs and perspective images. All images were presented in both gaze-contingent and normal viewing conditions. Consistent with a holistic processing model, we expected two results: (1) architects would display a greater difference in saccadic amplitude between the gaze-contingent and normal conditions, and (2) architects would spend less time per search than an undergraduate control group. We found that the architects were more accurate in the perspectival task, but they took more time and displayed a lower difference in saccadic amplitude than the controls. Our research indicates a disjunctive conclusion. Either architects are simply different kinds of visual experts than those previously studied, or we have generated a task that employs visual expertise without holistic processing. Our data suggest a healthy skepticism for across-the-board inferences collected from a single domain of expertise to the nature of visual expertise generally. More work is needed to determine whether holism is a feature of all visual expertise.

Noise, uncertainty, and interest: Predictive coding and cognitive penetration.

This paper concerns how extant theorists of predictive coding conceptualize and explain possible instances of cognitive penetration. Section 1 offers brief clarification of the predictive coding framework and of cognitive penetration. Section 2 develops more precise ways that the predictive coding framework can explain genuine top-down causal effects on perceptual experience. Section 3 develops these insights further with an eye towards tracking one extant criterion for cognitive penetration, namely, that the relevant cognitive effects on perception must be sufficiently direct. In Section 4, we analyze and criticize a claim made by some theorists of predictive coding, namely, that (interesting) instances of cognitive penetration tend to occur in perceptual circumstances involving substantial noise or uncertainty. We argue that, when applied, the claim fails to explain (or perhaps even be consistent with) a large range of important and uncontroversially interesting possible cases of cognitive penetration. We conclude with a general speculation about how the recent work on the predictive mind may influence the current dialectic concerning top-down effects on perception.