Visual noise consisting of X-junctions has only a minimal adverse effect on object recognition Abstract In 1968, Guzman showed that the myriad of surfaces composing a highly complex and novel assemblage of volumes can readily be assigned to their appropriate volumes in terms of the constraints offered by the vertices of coterminating edges. Of particular importance was the L-vertex, produced by the cotermination of two contours, which provides strong evidence for the termination of a 2-D surface. An X-junction, formed by the crossing of two contours without a change of direction at the crossing, played no role in the segmentation of a scene. If the potency of noise elements to affect recognition performance reflects their relevancy to the segmentation of scenes, as was suggested by Guzman, gaps in an object’s contours bounded by irrelevant X-junctions would be expected to have little or no adverse effect on shape-based object recognition, whereas gaps bounded by L-junctions would be expected to have a strong deleterious effect when they disrupt the smooth continuation of contours. Guzman’s roles for the various vertices and junctions have never been put to systematic test with respect to human object recognition. By adding identical noise contours to line drawings of objects that produced either L-vertices or X-junctions, these shape features could be compared with respect to their disruption of object recognition. Guzman’s insights that irrelevant L-vertices should be highly disruptive and irrelevant X-vertices would have only a minimal deleterious effect were confirmed.

Interacting hands draw attention during scene observation Abstract In this study I examined the role of the hands in scene perception. In Experiment 1, eye movements during free observation of natural scenes were analyzed. Fixations to faces and hands were compared under several conditions, including scenes with and without faces, with and without hands, and without a person. The hands were either resting (e.g., lying on the knees) or interacting with objects (e.g., holding a bottle). Faces held an absolute attentional advantage, regardless of hand presence. Importantly, fixations to interacting hands were faster and more frequent than those to resting hands, suggesting attentional priority to interacting hands. The interacting-hand advantage could not be attributed to perceptual saliency or to the hand-owner (i.e., the depicted person) gaze being directed at the interacting hand. Experiment 2 confirmed the interacting-hand advantage in a visual search paradigm with more controlled stimuli. The present results indicate that the key to understanding the role of attention in person perception is the competitive interaction among objects such as faces, hands, and objects interacting with the person.

The space contraction asymmetry in Michotte’s launching effect Abstract Previous studies have found that, compared with noncausal events, spatial contraction exists between the causal object and the effect object due to the perceived causality. The present research aims to examine whether the causal object and the effect object have the same effect on spatial contraction. A modified launching effect, in which a bar bridges the spatial gap between the final position of the launcher and the initial position of the target, was adopted. Experiment 1 validates the absolute underestimation of the bar’s length between the launcher and the target. Experiment 2a finds that in the direct launching effect, the perceived position of the bar’s trailing edge that was contacted by the final launcher was displaced along the objects’ direction of movement. Meanwhile, the perceived position of the bar’s leading edge that was contacted by the initial target was displaced in opposite direction to the moving direction. The magnitude of the former’s displacement was significantly larger than that of the latter, displaying a significant contraction asymmetry. Experiment 2b demonstrates that the contraction asymmetry did not result from the launcher remaining in contact with the edge of the bar. Experiment 3 indicates that contraction asymmetry showed a type of postdictive effect; that is, to some extent, this asymmetry depends on what happens after contact. In conclusion, the space between the causal object and effect object contracts asymmetrically in the launching effect, which implies that the causal object and effect object are perceived as shifting toward each other nonequidistantly in visual space.

Dwelling on simple stimuli in visual search Abstract Research and theories on visual search often focus on visual guidance to explain differences in search. Guidance is the tuning of attention to target features and facilitates search because distractors that do not show target features can be more effectively ignored (skipping). As a general rule, the better the guidance is, the more efficient search is. Correspondingly, behavioral experiments often interpreted differences in efficiency as reflecting varying degrees of attentional guidance. But other factors such as the time spent on processing a distractor (dwelling) or multiple visits to the same stimulus in a search display (revisiting) are also involved in determining search efficiency. While there is some research showing that dwelling and revisiting modulate search times in addition to skipping, the corresponding studies used complex naturalistic and category-defined stimuli. The present study tests whether results from prior research can be generalized to more simple stimuli, where target-distractor similarity, a strong factor influencing search performance, can be manipulated in a detailed fashion. Thus, in the present study, simple stimuli with varying degrees of target-distractor similarity were used to deliver conclusive evidence for the contribution of dwelling and revisiting to search performance. The results have theoretical and methodological implications: They imply that visual search models should not treat dwelling and revisiting as constants across varying levels of search efficiency and that behavioral search experiments are equivocal with respect to the responsible processing mechanisms underlying more versus less efficient search. We also suggest that eye-tracking methods may be used to disentangle different search components such as skipping, dwelling, and revisiting.

Comparable search efficiency for human and animal targets in the context of natural scenes Abstract In a previous series of studies, we have shown that search for human targets in the context of natural scenes is more efficient than search for mechanical targets. Here we asked whether this search advantage extends to other categories of biological objects. We used videos of natural scenes to directly contrast search efficiency for animal and human targets among biological or nonbiological distractors. In visual search arrays consisting of two, four, six, or eight videos, observers searched for animal targets among machine distractors, and vice versa (Exp. 1). Another group searched for animal targets among human distractors, and vice versa (Exp. 2). We measured search slope as a proxy for search efficiency, and complemented the slope with eye movement measurements (fixation duration on the target, as well as the proportion of first fixations landing on the target). In both experiments, we observed no differences in search slopes or proportions of first fixations between any of the target–distractor category pairs. With respect to fixation durations, we found shorter on-target fixations only for animal targets as compared to machine targets (Exp. 1). In summary, we did not find that the search advantage for human targets over mechanical targets extends to other biological objects. We also found no search advantage for detecting humans as compared to other biological objects. Overall, our pattern of findings suggests that search efficiency in natural scenes, as elsewhere, depends crucially on the specific target–distractor categories.

Is it impossible to acquire absolute pitch in adulthood? Abstract Absolute pitch (AP) refers to the rare ability to name the pitch of a tone without external reference. It is widely believed to be only for the selected few with rare genetic makeup and early musical training during the critical period, and therefore acquiring AP in adulthood is impossible. Previous studies have not offered a strong test of the effect of training because of issues like small sample size and insufficient training. In three experiments, adults learned to name pitches in a computerized, gamified and personalized training protocol for 12 to 40 hours, with the number of pitches gradually increased from three to twelve. Across the three experiments, the training covered different octaves, timbre, and training environment (inside or outside laboratory). AP learning showed classic characteristics of perceptual learning, including generalization of learning dependent on the training stimuli, and sustained improvement for at least one to three months. 14% of the participants (6 out of 43) were able to name twelve pitches at 90% or above accuracy, comparable to that of ‘AP possessors’ as defined in the literature. Overall, AP continues to be learnable in adulthood, which challenges the view that AP development requires both rare genetic predisposition and learning within the critical period. The finding calls for reconsideration of the role of learning in the occurrence of AP, and pushes the field to pinpoint and explain the differences, if any, between the aspects of AP more trainable in adulthood and the aspects of AP that are potentially exclusive for the few exceptional AP possessors observed in the real world.

Correction to: How to correctly put the “subsequent” in subsequent search miss errors The following formatting changes to the figures and table need to be made in order to enhance readability.

Correction to: Visual search asymmetry depends on target-distractor feature similarity: Is the asymmetry simply a result of distractor rejection speed? In the original version of the published article the stimuli in Table 2 and Figure 2 were displayed incorrectly.

Correction to: Detecting distortions of peripherally presented letter stimuli under crowded conditions We discovered an error in the implementation of the function used to generate radial frequency (RF) distortions1 in our article (Wallis, Tobias, Bethge, & Wichmann, 2017).

How to correctly put the “subsequent” in subsequent search miss errors Abstract Visual search, finding targets among distractors, is theoretically interesting and practically important as it involves many cognitive abilities and is vital for several critical industries (e.g., radiology, baggage screening). Unfortunately, search is especially error prone when more than one target is present in a display (a phenomenon termed the satisfaction of search effect or the subsequent search miss effect). The general effect is that observers are more likely to miss a second target if a first was already detected. Unpacking the underlying mechanisms requires two key aspects in analysis and design. First, to speak to the “subsequent” nature of the effect, the analyses must compare performance on single-target trials to performance for a second target in dual-target displays after a first has been found. Second, the design must include single-target displays that are matched in difficulty to each dual-target display to enable fair comparisons. However, it is not clear that prior research has met these two standards simultaneously. Work from academic radiology has primarily used designs with well-matched single- and dual-target trials, but most employed analyses that do not focus solely on performance after a first target has been detected. Work from cognitive psychology has generally performed the correct analyses, but relied on unmatched single- and dual-target trials, introducing a confound that could distort the results. In the current paper, we demonstrate the impact of this confound in empirical data and provide a roadmap for proper study design and analyses.