What makes triangles point: Local and global effects in configurations of ambiguous triangles

Perceived pointing of ambiguous triangles was investigated in three experiments. The results show that the probability of seeing an equilateral triangle point in a given direction is strongly influenced by (a) the direction of the ambiguous alternatives, (b) the orientational characteristics of the configuration of elements surrounding the triangle, and (c) the shape of the surrounding elements. These findings are interpreted as supporting the hypothesis that perceived pointing is determined by perceptual reference frames induced at multiple levels of globality: one for the general visual field, one for the entire configuration, and one for the local elements of the configuration.     

Grounding the figure: Surface attachment influences figure-ground organization

We investigated whether the lower region effect on figure-ground organization (Vecera, Vogel, & Woodman, 2002) would generalize to contextual depth planes in vertical orientations, as is predicted by a theoretical analysis based on the ecological statistics of edges arising from objects that are attached to surfaces of support. Observers viewed left/right ambiguous figure-ground displays that occluded middle sections of four types of contextual inducers: two types of attached, receding, vertical planes (walls) that used linear perspective and/or texture gradients to induce perceived depth and two types of similar trapezoidal control figures that used either uniform color or random texture to reduce or eliminate perceived depth. The results showed a reliable bias toward seeing as “figure” the side of the figure-ground display that was attached to the receding depth plane, but no such bias for the corresponding side in either of the control conditions. The results are interpreted as being consistent with the attachment hypothesis that the lower region cue to figure-ground organization results from ecological biases in edge interpretation that arise when objects are attached to supporting surfaces in the terrestrial gravitational field.     

Response of female cuttlefish Sepia officinalis (Cephalopoda) to mirrors and conspecifics: evidence for signaling in female cuttlefish

Cuttlefish have a large repertoire of body patterns that are used for camouflage and interspecific signaling. Intraspecific signaling by male cuttlefish has been well documented but studies on signaling by females are lacking. We found that females displayed a newly described body pattern termed Splotch toward their mirror image and female conspecifics, but not to males, prey or inanimate objects. Female cuttlefish may use the Splotch body pattern as an intraspecific signal, possibly to reduce agonistic interactions. The ability of females to produce a consistent body pattern in response to conspecifics and mirrors suggests that they can recognize same-sex conspecifics using visual cues, despite the lack of sexual dimorphism visible to human observers. Electronic Supplementary Material Supplementary material is available for this article at and is accesible for authorized users.     

Effects of hearing the past, present, or future during music performance

Three experiments were performed to explore the effects of mismatches between actions (key-presses) and the contents of auditory feedback (pitch events) during music performance. Pianists performed melodies from memory during altered auditory feedback that was synchronized with key-presses but matched the pitch of other sequence events. Feedback direction was manipulated by presenting pitches that matched events intended for the past (delays; Experiments 1 and 3) or the future (prelays; Experiments 2 and 3). Feedback distance was manipulated by varying the absolute separation between the current event and the location of the feedback pitch. All alterations disrupted the accuracy of performance (pitch errors) more so than timing. Serial-ordering errors indicated confusions among proximal and metrically similar events, consistent with the predictions of an incremental planning model (Palmer & Pfordresher, 2003). Patterns of serial-ordering errors suggested that performers compensate for the disruptive effects of altered feedback by changing event activations during planning.     

Accountability and need for cognition effects on contrast, halo, and accuracy in performance ratings

In the present study, the authors investigated the effects of accountability and need for cognition on contrast errors, halo, and accuracy of performance ratings examined in good and poor performance context conditions, as well as in a context-free control condition. The accountability manipulation reduced the contrast effect and also modified rater recall of good ratee behavior. Accountability reduced halo in ratings and increased rating accuracy in a poor performance context. Accountability also interacted with need for cognition in predicting individual rater halo.     

Factors influencing inhibitory stimulus control: discrimination training and prior non-differential reinforcement

In Exp. I, shallow U-shaped gradients of inhibition in the line-orientation dimension were obtained from birds that had a vertical (0°) line on a green surround correlated with extinction and a blank green surround correlated with reinforcement. Birds that had massed extinction in the presence of the 0° line showed flat gradients. Thus, discrimination training, but not massed extinction, appears to generate inhibitory control. In Exp. II, as in studies of control by a stimulus correlated with punishment, non-differential training across the line-orientation dimension preceded further sessions. Steep inverted gradients about the 0° line were obtained after discrimination training with the 0° line correlated with extinction. Gradients obtained after massed extinction tended to be flat. Again, discrimination training was critical in obtaining negative gradients of stimulus control.     

Factorial design in the determination of differential limen values

This paper discusses the application of the principles of factorial design to an experiment in psychology. For the purpose of illustrating the principles, a simple experiment was designed dealing with the determination of the differential limen values of subjects for weights increasing at constant rates. The factorial design was of the type: 4 rates × 7 weights × 2 sexes × 2 sights × 2 dates. The appropriate statistical analysis for this type of design is the analysis of variance. The mathematical formulation of the problem was specified and the appropriate solution for the specific problem was obtained. Greater precision results from this type of design, in comparison with the traditional psychological experiment dealing with a single factor, in that measures are obtained of the effect of each of a number of factors together with their interactions.This is one of a number of studies on modern principles of experimental design. For the research grant to finance these studies, grateful acknowledgment is given to the Graduate School, the University of Minnesota.     

How similar is similar enough? Job profile similarity benchmarks using occupational information network data

Job comparison research is critical to many human resources initiatives, such as transporting validity evidence. Job analysis methods often focus on critical attribute (e.g., tasks, work behaviors) overlap when assessing similarity, but profile similarity metrics represent an alternative or complementary approach for job comparisons. This paper utilizes Occupational Information Network (O*NET) data to establish a distribution of job profile correlations across all job pairs for five attributes – generalized work activities, knowledge, skills, abilities, and work styles. These correlations represent effect sizes, or degree of shared variance between jobs. Practitioners may reference these correlational distributions as benchmarks for gauging the practical significance of the observed degree of similarity between two jobs of interest compared to the broader world of work.     

Of Signs: Matter and Revelation in the Liturgies of William Durand and John Calvin

This article seeks to set aside what we might call Cartesian physics to revisit William Durand's conception of sign as set forth in the Rationale divinorum officiorum and John Calvin's as set forth in the Institutio christianae religionis. Reading the two works through the lens of medieval physics reveals commonalities – both held signs to be ever-present modes of divine communication – and enables us to delineate more precisely their differences. For both, creation was a locus of divine communication. For Durand, the position of a faithful person was observation informed by Scripture, an attentiveness to the redundantia of divine communication in which Scripture and creation were in dialectic. For Calvin, divine communication was simultaneously visible and, to fallen humankind, imperceptible: even as creation held forth divine signs, human beings could not comprehend them. These differing conceptions of the human observer (Durand) or spectator (Calvin), precede and ground their differing approaches to eucharistic signs.     

Liberal reformers or militant radicals: What are the effects of education in the social sciences?

The assertion by Baer and Lambert (1990) that social science training does not promote radicalism, is tested in two studies. The first, using a sample of politically active students from Montréal (N=68) and measures of radical ideology and political convictions, shows social science students are over-represented among politically active students, and more likely to espouse radical ideology and label themselves members of groups aiming to restructure society, than students from other fields. The second study compares first and third-year social science students from Toronto (N=99) on measures of radical ideology, attitudes toward groups favouring change or the status quo, and causal attributions regarding poverty and unemployment. Results suggest social science training fosters positive evaluations of groups seeking change, espousal of radical ideology, tendency to fault the system for social problems, decrease in tendency to fault individuals, and development of a coherent ideological framework. Implications for academic socialization theories and methodological issues are discussed. Université Blaise Pascal This research was supported in part by grants from the Social Science and Humanities Research Council and from the Academic Research Program of the Department of National Defence of Canada awarded to the first author. The opinions expressed herein are those of the authors and do not necessarily reflect the views of the institutions with which they are affiliated. The authors would like to thank Dr. Stuart Lawson, at the Psychology Department at Queen's University, Kingston, for the use of his program comparing correlation matrices. We would also like to acknowledge the helpful comments of Editor Bruce J. Biddle.