Perceptual saliency of points along the contour of everyday objects: a large-scale study

The aim of this large-scale study was to find out which points along the contour of a shape are most salient and why. Many subjects (N=161) were asked to mark salient points on contour stimuli, derived from a large set of line drawings of everyday objects (N=260). The database of more than 200,000 marked points was analyzed extensively to test the hypothesis, first formulated by Attneave (1954), that curvature extrema are most salient. This hypothesis was confirmed by the data: Highly salient points are usually very close to strong curvature extrema (positive maxima and negative minima). However, perceptual saliency of points along the contour is determined by more factors than just local absolute curvature. This was confirmed by an extensive correlational analysis of perceptual saliency in relation to ten different stimulus factors. A point is more salient when the two line segments connecting it with its two neighboring salient points make a sharp turning angle and when the 2-D part defined by the triplet of salient points is less compact and sticks out more.     

The effects of symmetry and contour on recognition memory in children

Children in prekindergarten, kindergarten, and second grade were tested on a delayed match-to-sample task using abstract visual patterns. The patterns varied both in type of visual organization (unstructured, diagonally symmetrical, vertically symmetrical, and horizontally symmetrical) and in amount of contour. Following the initial memory task, we attempted to train half of the children at each grade by directing their attention to axes of symmetry; the other half of the children received a control task. Subsequently, the subjects were given a second delayed match-to-sample test. On both pre- and post-training trials, structure influenced performance, especially in the two younger groups. Vertical and horizontal symmetry generally facilitated performance in the prekindergarteners, while all three types of symmetry facilitated performance in the kindergarteners. In addition, children generally responded more accurately to patterns with lower levels of contour. They also made more like-contour than unlike-contour confusions, indicating that quantitative aspects of patterns were encoded. Group differences suggested that both processing capacity and memory increase during the age range studied. Finally, there was no indication that training improved performance at any age.     

The influence of contour fragmentation on recognition memory: an event-related potential study

The present study was carried out to examine how the event-related potentials to fragmentation predict recognition success. Stimuli were abstract meaningless figures that were either complete or fragmented to various extents but still recoverable. Stimuli were first encoded as part of a symmetry discrimination task. In a subsequent recognition phase, encoded stimuli were presented complete along with never presented stimuli and participants performed an old/new discrimination task. Fragmentation stimuli elicited more negative ERPs than complete figures over the frontal, central and parietal areas between 180 and 260 ms, and over the occipito-temporal areas between 220 and 340 ms. Only this latter effect was modulated as a function of whether stimuli were recognized or not during the recognition phase of the memory test. More specifically, the effect occurred for stimuli that were later forgotten and was absent for stimuli that were later recognized. This ERP to fragmentation, the occipito-temporal N(frag), possibly reflects the brain response to encoding difficulty, and is thus predictive of recognition performance.     

Effects of length,tonal structure,and contour in the recognition of tone series

Four experiments on recognition of tone series are reported. The first experiment tested the accuracy of recognition in relation to length, contour complexity, and tonal structure of the series. Series comprised (1) 7 or 10 tones, (2) either a strong or a weak tonal structure, depending on the temporal ordering of the tones, and (3) few or many contour reversals. The second experiment used 7-tone series having either a strong or a weak tonal structure, depending on the mode (Ionian or Phrygian) in which the series was presented. Both experiments employed asamedifferent task in which a standard series was compared with either an exact or an inexact transposition, the latter type having one incorrectly transposed tone (mostly nondiatonic in Experiment 1 and always diatonic in Experiment 2) These experiments showed that (1) 7-tone series were better recognized than were 10-tone series, (2) series with a strong tonal structure were better recognized than were series with a weak tonal structure, and (3) contour complexity did not influence the responses. Two control experiments, using mistuned tone series, showed that the outcomes of Experiments 1 and 2 could not be attributed to nonmusical artifacts of the stimulus set.     

Context change and the role of meaning in word recognition

Two experiments were conducted in which the central variable was the addition of verbal context on the test which was not present during study. Neither study showed context to be a relevant variable. Because verbal context effects (when they do occur) are presumed to result from a change of meaning, the broader role of word meaning in recognition was examined. Studies in which homographs were used to produce a change in meaning were reviewed with the conclusion that when appropriate controls are used the effects are too small to support meaning as a major factor underlying recognition. An experiment using homographs verified the general conclusion from previous studies. A review of studies was then undertaken to determine the influence of synonym distractors on recognition scores. If word meaning is critical in word recognition, the use of synonyms of study words as new words on the recognition test should produce large decrements. The evidence available did not support this expectation, and an experiment using both within-subject and between-subject comparisons showed at best only small effects. The general conclusion was that theories of recognition in which word meaning plays a dominant role cannot be supported. It is likely that word meaning is encoded during study of lists of words but is infrequently used in making recognition decisions.     

Categorical templates are more useful when features are consistent: Evidence from eye movements during search for societally important vehicles

Unlike in laboratory visual search tasks—wherein participants are typically presented with a pictorial representation of the item they are asked to seek out—in real-world searches, the observer rarely has veridical knowledge of the visual features that define their target. During categorical search, observers look for any instance of a categorically defined target (e.g., helping a family member look for their mobile phone). In these circumstances, people may not have information about noncritical features (e.g., the phone’s color), and must instead create a broad mental representation using the features that define (or are typical of) the category of objects they are seeking out (e.g., modern phones are typically rectangular and thin). In the current investigation (Experiment 1), using a categorical visual search task, we add to the body of evidence suggesting that categorical templates are effective enough to conduct efficient visual searches. When color information was available (Experiment 1a), attentional guidance, attention restriction, and object identification were enhanced when participants looked for categories with consistent features (e.g., ambulances) relative to categories with more variable features (e.g., sedans). When color information was removed (Experiment 1b), attention benefits disappeared, but object recognition was still better for feature-consistent target categories. In Experiment 2, we empirically validated the relative homogeneity of our societally important vehicle stimuli. Taken together, our results are in line with a category-consistent view of categorical target templates (Yu, Maxfield, & Zelinsky in, Psychological Science, 2016. doi: 10.1177/0956797616640237), and suggest that when features of a category are consistent and predictable, searchers can create mental representations that allow for the efficient guidance and restriction of attention as well as swift object identification.     

Age-related differences in recognition memory: effects of materials and context change

The study explored age-related differences in the effects of context change on recognition memory by presenting object names (Expt. 1A) or their pictures (Expt. 1B) on background scenes. Participants later attempted to recognize previously presented items on background scenes that were original, switched, blank, or new. Older adults recognized fewer word stimuli than did younger adults, and context effects were larger for older adults. With pictures, however, the age-related decrement was eliminated and context effects were reduced. The beneficial effect of context reinstatement in older adults occurs despite the finding that they are less able to recall or recognize such contexts (Experiment 2). Older adults can use context information in recognition memory at least as efficiently as younger adults when suitable materials and conditions are provided.     

Permanence and change in memory: I. Reproduction and recognition of visual figures

Abstract.— A retroactive interference paradigm was employed for studying qualitative memory changes. The name given to an ambiguous visual figure after presentation influenced reproduction and, to a lesser extent, recognition of the figure, indicating that retroactive definition of meaning may lead to memory changes. The relation between the subject's own conception of the meaning of the figure and the name given by the experimenter involved several types of meaning retroaction, which were related to the results on the remembering tasks. The usual interpretation—in line with the permanent-memory hypothesis—attributing changed reproductions either to perceptual change or to interference with the activity of drawing, is not accepted, and a contextual theory of memory is suggested.     

People are not cabbages: reflections on patient and analyst change

The author describes how her own internal change was a vital part of transformation between herself and two patients. She draws on Loewald's work as she discusses how change in her own internal relationship with her father was part of a lifelong emotional reorganization of Oedipal relations. She describes a process of mutual change whereby her and her patients' unconscious growth each stimulated the other. She suggests that the analyst's own emotional growth is a vital, not an incidental, part of psychoanalysis, as it brings new life to the work for patients as well as analysts themselves.     

There are at least two kinds of probability matching: evidence from a secondary task

Probability matching is a suboptimal behavior that often plagues human decision-making in simple repeated choice tasks. Despite decades of research, recent studies cannot find agreement on what choice strategies lead to probability matching. We propose a solution, showing that two distinct local choice strategies—which make different demands on executive resources—both result in probability-matching behavior on a global level. By placing participants in a simple binary prediction task under dual- versus single-task conditions, we find that individuals with compromised executive resources are driven away from a one-trial-back strategy (utilized by participants with intact executive resources) and towards a strategy that integrates a longer window of past outcomes into the current prediction. Crucially, both groups of participants exhibited probability-matching behavior to the same extent at a global level of analysis. We suggest that these two forms of probability matching are byproducts of the operation of explicit versus implicit systems.     

Phonological priming in auditory word recognition: when both controlled and automatic processes are responsible for the effects.

The phonological priming paradigm provides an interesting methodological tool for studying various components of the speech recognition process. However, concerns about response biases distorting the effects have been repeatedly voiced. This article reviews the main studies on priming and aims to distinguish effects under automatic processes from those under some level of strategic control. Both controlled and automatic processes appear to be responsible for the effects observed in phonological priming experiments. Nonetheless, with careful procedures, it is possible to separate them.     

Face recognition: Effects of study to test maintenance and change of photographic mode and pose

Facial recognition performance was examined as a function of changes in the target between initial exposure (study) and a subsequent recognition test. Photographic mode (colour vs. black and white) was changed in Experiments 1 and 2 and pose (front vs. profile) was changed in Experiment 2. The predictions of three information quantity models and of encoding specificity were contrasted. The information hypotheses predict that colour photographs will be better recognized when presented in colour than in black and white; the more specific predictions differ depending on the modes at study and test. Encoding specificity predicts recognition performance will be better when study and test modes are the same. The results of Experiment 1 showed that performance was highest when pictures remained in the same mode from study to test, and decreased when the mode was changed. Change of mode was particularly detrimental when the faces were studied in black and white and tested in colour. Experiment 2 showed a pattern of results also in accord with encoding specificity. The photographic mode and pose effects did not interact. Change of pose had a greater effect than change of photographic mode. Experiment 2 did not replicate the transformation asymmetry found in Experiment 1. The results indicate that for facial recognition memory, change lowers recognition, but the magnitude of the effect depends on the kind of change.     

Spatial frequency thresholds for face recognition when comparison faces are filtered and unfiltered

Previous work has shown an advantage of middle spatial frequencies (SFs) in face recognition. However, a few recent studies have suggested that this advantage is reduced when comparison and test stimuli are spatially filtered in a similar way. In the present study, we used standard psychophysical methods, in combination with a match-to-sample task, to determine the SF thresholds for face matching under conditions in which: (1) comparison stimuli were unfiltered and (2) comparison stimuli were spatially filtered in the same way as test stimuli. In two experiments, we show that SFs closer to the middle band are sought out more in the former case than in the latter. These results are compatible with the idea that a middle band of SFs will be most useful for any visual task and that the breadth of this optimal middle band will vary depending on task characteristics.     

Features are also important: contributions of featural and configural processing to face recognition

It has been suggested that face recognition is primarily based on configural information, with featural information playing little or no role. We investigated this idea by comparing the prototype effect for face prototypes that emphasized either featural or configural processing. In Experiment 1, participants showed a tendency to commit false alarms in response to nonstudied prototypes, and this tendency was equivalent for featural and configural prototypes. Experiment 2 replicated this finding, and provided support for the assumption that the two types of prototypes differed in terms of featural and configural processing: Face inversion eliminated the prototype effect for configural prototypes but not for featural prototypes. These results suggest that both featural and configural processing make important contributions to face recognition, and that their effects are dissociable.     

Anomalies in the detection of change: When changes in sample size are mistaken for changes in proportions

Detecting changes, in performance, sales, markets, risks, social relations, or public opinions, constitutes an important adaptive function. In a sequential paradigm devised to investigate detection of change, every trial provides a sample of binary outcomes (e.g., correct vs. incorrect student responses). Participants have to decide whether the proportion of a focal feature (e.g., correct responses) in the population from which the sample is drawn has decreased, remained constant, or increased. Strong and persistent anomalies in change detection arise when changes in proportional quantities vary orthogonally to changes in absolute sample size. Proportional increases are readily detected and nonchanges are erroneously perceived as increases when absolute sample size increases. Conversely, decreasing sample size facilitates the correct detection of proportional decreases and the erroneous perception of nonchanges as decreases. These anomalies are however confined to experienced samples of elementary raw events from which proportions have to be inferred inductively. They disappear when sample proportions are described as percentages in a normalized probability format. To explain these challenging findings, it is essential to understand the inductive-learning constraints imposed on decisions from experience.