Many experiments have investigated visual search for simple stimuli like colored bars or alphanumeric characters. When eye movements are not a limiting factor, these tasks tend to produce roughly linear functions relating reaction time (RT) to the number of items in the display (set size). The slopes of the RT × set size functions for different searches fall on a continuum from highly efficient (slopes near zero) to inefficient (slopes > 25-30 msec/item). Many theories of search can produce the correct pattern of mean RTs. Producing the correct RT distributions is more difficult. In order to guide future modeling, we have collected a very large data set (about 112,000 trials) on three tasks: an efficient color feature search, an inefficient search for a 2 among 5s, and an intermediate color × orientation conjunction search. The RT distributions have interesting properties. For example, target absent distributions overlap target present more than would be expected if the decision to end search were based on a simple elapsed time threshold. Other qualitative properties of the RT distributions falsify some classes of model. For example, normalized RT distributions do not change shape as set size changes as a standard self-terminating model predicts that they should.

Many visual search experiments measure reaction time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of information. For this paper, we collected about 500 trials per cell per observer for both target-present and target-absent displays in each of three classic search tasks: feature search, with the target defined by color; conjunction search, with the target defined by both color and orientation; and spatial configuration search for a 2 among distractor 5s. This large data set allows us to characterize the RT distributions in detail. We present the raw RT distributions and fit several psychologically motivated functions (ex-Gaussian, ex-Wald, Gamma, and Weibull) to the data. We analyze and interpret parameter trends from these four functions within the context of theories of visual search. Keywordsvisual search; response time distributions; Gamma; ex-Gaussian; ex-Wald; WeibullThe visual search paradigm, in which an observer looks for a target among a varying number of distractors, has been an important tool for evaluating theories of visual selective attention for thirty years now (e.g., Duncan & Humphreys, 1989, 1992Treisman & Gelade, 1980;Treisman & Gormican, 1988;Treisman & Sato, 1990;Wolfe, 1994;Wolfe, Cave, & Franzel, 1989). In much of the visual search literature, the principle independent variable is the number of items in the search array (set size), and the principle dependent variable is mean or median response time (RT). The slope of the resulting RT × set size function (search slope) indexes the efficiency of search. This method has proven to be valuable for understanding visual features, attentional capture, neuropsychological disorders, and so forth (for reviews, see

Humans see whole objects from input fragmented in space and time, yet spatiotemporal object perception is poorly understood. The authors propose the theory of spatiotemporal relatability (STR), which describes the visual information and processes that allow visible fragments revealed at different times and places, due to motion and occlusion, to be assembled into unitary perceived objects. They present a formalization of STR that specifies spatial and temporal relations for object formation. Predictions from the theory regarding conditions that lead to unit formation were tested and confirmed in experiments with dynamic and static, occluded and illusory objects. Moreover, the results support the identity hypothesis of a common process for amodal and modal contour interpolation and provide new evidence regarding the relative efficiency of static and dynamic object formation. STR postulates a mental representation, the dynamic visual icon, that briefly maintains shapes and updates positions of occluded fragments to connect them with visible regions. The theory offers a unified account of interpolation processes for static, dynamic, occluded, and illusory objects.

In psychology research studies, the goals of the experimenter and the goals of the participants often do not align. Researchers are interested in having participants who take the experimental task seriously, whereas participants are interested in earning their incentive (e.g., money or course credit) as quickly as possible. Creating experimental methods that are pleasant for participants and that reward them for effortful and accurate data generation, while not compromising the scientific integrity of the experiment, would benefit both experimenters and participants alike. Here, we explored a gamelike system of points and sound effects that rewarded participants for fast and accurate responses. We measured participant engagement at both cognitive and perceptual levels and found that the point system (which invoked subtle, anonymous social competition between participants) led to positive intrinsic motivation, while the sound effects (which were pleasant and arousing) led to attentional capture for rewarded colors. In a visual search task, points were awarded after each trial for fast and accurate responses, accompanied by short, pleasant sound effects. We adapted a paradigm from Anderson, Laurent, and Yantis (Proceedings of the National Academy of Sciences 108(25):10367-10371, 2011b), in which participants completed a training phase during which red and green targets were probabilistically associated with reward (a point bonus multiplier). During a test phase, no points or sounds were delivered, color was irrelevant to the task, and previously rewarded targets were sometimes presented as distractors. Significantly longer response times on trials in which previously rewarded colors were present demonstrated attentional capture, and positive responses to a five-question intrinsic-motivation scale demonstrated participant engagement.

Significant effects were found for protocols across provider types, regardless of expertise or area of clinical focus. It also appears that more thorough protocols lead to more information being passed, especially when those protocols consist of 12 or more items. Given these findings, publication bias is an apparent feature of this literature base. Recommendations to reduce the apparent publication bias in the field include changing the way articles are screened and published.