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.     

Measurement of newcomer socialization: Construct validation of a multidimensional scale

A construct validation approach was taken to develop a primary measure of newcomer socialization that addresses shortcomings with a prior scale (Chao, Kelly, Wolf, Klein, & Gardner, 1994). Three separate groups of subject matter experts reviewed items to ensure the content validity of the Newcomer Socialization Questionnaire (NSQ). Studies 1 and 2 examined the NSQ’s psychometric properties using employed students and organizational newcomers as participants, respectively. Results illustrate scale reliability, factor structure, convergent and discriminant validity, and correlations with criterion variables. The NSQ measures three dimensions or domains of newcomer socialization: the organization, the group and the job/task. In addition, both factual knowledge and knowledge of expected role behaviors are assessed within each domain. Thus, the NSQ provides a useful measurement tool for researchers and practitioners interested in examining direct outcomes of being socialized.     

Gender, social class, and the subjective experience of aging: self-perceived personality change from early adulthood to late midlife

This study explored the applicability of previous research (obtained with groups of college-educated women) about the subjective experience of aging in midlife to men and less-educated people. Two-hundred fifty-nine men and women who graduated from a public high school in 1955-1957 retrospectively assessed their feelings of identity certainty, confident power, generativity, and concern about aging for their 60s, 40s, and 20s. Participants reported higher levels of identity certainty, confident power, and concern about aging at each age, and a leveling off of generativity in their 60s. There were some gender and social class differences. Although men and women recalled the same trajectory of these feelings, men reported higher levels of identity certainty and confident power across age. Non-college-educated men recalled the highest levels of concern about aging across age. We discuss how these findings add to our understanding of the experience of aging in these domains.     

Previous reward decreases errors of commission on later ‘No‐Go’ trials in children 4 to 12 years of age: evidence for a context monitoring account

Inhibitory control is widely hypothesized to be the cornerstone of executive function in childhood and the central deficit in a number of developmental disorders, including attention‐deficit/hyperactivity disorder (ADHD). However, recent evidence from adults indicates that performance on response inhibition tasks may primarily reflect non‐inhibitory attentional control (context monitoring) processes. Yet it may be that inhibition plays a more central role in childhood – a time when the architecture of cognitive processes might be more transparent due to wide variability in skill level. Here we directly test inhibitory and context monitoring explanations of task performance on a Go/No‐Go task in a large group of children 4–12 years of age. We conclude that traditional inhibitory conceptualizations of task performance on the Go/No‐Go task cannot account for our findings, calling into question evidence supporting a central role for inhibitory control in cognitive development or developmental psychopathology.     

A novel view of between-categories contrast and within-category assimilation

This research manipulated the portion of a category distribution that is misclassified by the optimal classifier and investigated the impact on assessments of category attributes. Three separate studies manipulated the direction of overlap, the extent of overlap, and the relative base rate of the comparison category. All 3 studies produced large between-categories contrast and within-category assimilation. As expected, these effects were enhanced in conditions in which the optimal classifier misclassified a larger portion of the target category. Study 4 demonstrated that intercategory overlap in the absence of overt classification does not produce contrast and assimilation. Ironically, optimizing categorization accuracy can produce highly inaccurate beliefs about category attributes.     

The psychophysics of uneconomical choice: non-linear reward evaluation by a nectar feeder

Uneconomical choices by humans or animals that evaluate reward options challenge the expectation that decision-makers always maximize the return currency. One possible explanation for such deviations from optimality is that the ability to sense differences in physical value between available alternatives is constrained by the sensory and cognitive processes for encoding profitability. In this study, we investigated the capacity of a nectarivorous bat species (Glossophaga commissarisi) to discriminate between sugar solutions with different concentrations. We conducted a two-alternative free-choice experiment on a population of wild electronically tagged bats foraging at an array of computer-automated artificial flowers that recorded individual choices. We used a Bayesian approach to fit individual psychometric functions, relating the strength of preferring the higher concentration option to the intensity of the presented stimulus. Psychometric analysis revealed that discrimination ability increases non-linearly with respect to intensity. We combined this result with a previous psychometric analysis of volume perception. Our theoretical analysis of choice for rewards that vary in two quality dimensions revealed regions of parameter combinations where uneconomic choice is expected. Discrimination ability may be constrained by non-linear perceptual and cognitive encoding processes that result in uneconomical choice.     

Ecological rationality or nested sets? Individual differences in cognitive processing predict Bayesian reasoning

The presentation of a Bayesian inference problem in terms of natural frequencies rather than probabilities has been shown to enhance performance. The effect of individual differences in cognitive processing on Bayesian reasoning has rarely been studied, despite enabling us to test process-oriented variants of the two main accounts of the facilitative effect of natural frequencies: The ecological rationality account (ERA), which postulates an evolutionarily shaped ease of natural frequency automatic processing, and the nested sets account (NSA), which posits analytical processing of nested sets. In two experiments, we found that cognitive reflection abilities predicted normative performance equally well in tasks featuring whole and arbitrarily parsed objects (Experiment 1) and that cognitive abilities and thinking dispositions (analytical vs. intuitive) predicted performance with single-event probabilities, as well as natural frequencies (Experiment 2). Since these individual differences indicate that analytical processing improves Bayesian reasoning, our findings provide stronger support for the NSA than for the ERA.     

Contour-based object identification and segmentation: Stimuli,norms and data,and software tools

We summarize five studies of our large-scale research program, in which we examined aspects of contour-based object identification and segmentation, and we report on the stimuli we used, the norms and data we collected, and the software tools we developed. The stimuli were outlines derived from the standard set of line drawings of everyday objects by Snodgrass and Vanderwart (1980). We used contour curvature as a major variable in all the studies. The total number of 1,500 participants produced very solid, normative identification rates of silhouettes and contours, straight-line versions, and fragmented versions, and quite reliable benchmark data about saliency of points and object segmentation into parts. We also developed several software tools to generate stimuli and to analyze the data in nonstandard ways. Our stimuli, norms and data, and software tools have great potential for further exploration of factors influencing contour-based object identification, and are also useful for researchers in many different disciplines (including computer vision) on a wide variety of research topics (e.g., priming, agnosia, perceptual organization, and picture naming). The full set of norms, data, and stimuli may be downloaded fromwww.psychonomic.org/archive/.