The role of discontinuities in the perception of subjective figures

Recently we proposed a theory of visual interpolation (Kellman & Shipley, in press) that addresses a variety of unit formation phenomena, including the perception of partly occluded objects and subjective figures. A basic notion of the theory is that discontinuities in the first derivative of projected edges are the initiating conditions for interpolation of boundaries that are not physically specified. In this paper, we report four experiments in which this claim was tested in the domain of subjective figures. Experiments 1 and 2 demonstrate that discontinuities in the first derivative of the edges of inducing elements have a clear effect on the frequency of report and the perceived clarity of simple subjective figures. Similar effects are found when unfamiliar subjective figures and inducing elements are used (Experiment 3). Experiment 4 rules out the possibility that the discontinuities in the first derivative merely add to the clarity of subjective figures. These experiments suggest that first-order discontinuities play a central role in unit formation.     

Simulation in hypnosis research: the "hidden" role of attribution of meaning

The role played by attribution of meaning in research involving simulation is examined. Acknowledgement of this role, lacking to date, queries the traditional use of simulation but also opens up interesting research questions.     

On the perception of speech from time-varying acoustic information: contributions of amplitude variation

The cyclic variation in the energy envelope of the speech signal results from the production of speech in syllables. This acoustic property is often identified as a source of information in the perception of syllable attributes, though spectral variation can also provide this information reliably. In the present study of the relative contributions of the energy and spectral envelopes in speech perception, we employed sinusoidal replicas of utterances, which permitted us to examine the roles of these acoustic properties in establishing or maintaining time-varying perceptual coherence. Three experiments were carried out to assess the independent perceptual effects of variation in sinusoidal amplitude and frequency, using sentence-length signals. In Experiment 1, we found that the fine grain of amplitude variation was not necessary for the perception of segmental and suprasegmental linguistic attributes; in Experiment 2, we found that amplitude was nonetheless effective in influencing syllable perception, and that in some circumstances it was crucial to segmental perception; in Experiment 3, we observed that coarse-grain amplitude variation, above all, proved to be extremely important in phonetic perception. We conclude that in perceiving sinusoidal replicas, the perceiver derives much from following the coherent pattern of frequency variation and gross signal energy, but probably derives rather little from tracking the precise details of the energy envelope. These findings encourage the view that the perceiver uses time-varying acoustic properties selectively in understanding speech.     

Similar processing of real- and subjective-contour Poggendorff figures by men and women

Measures of illusion magnitude for a real-contour and two subjective-contour Poggendorff figures were obtained from 42 men and 42 women. Although magnitudes of illusion differed as a function of figure type, male-female differences in magnitude of illusion did not vary across figures or judgment orders. Also, correlations among the illusions observed for three types of figures did not differ for men and women. These data are consistent with the view that real- and subjective-contour Poggendorff figures evoke similar processing strategies and that sex differences, when observed, are probably the result of differences in cognitive-judgmental strategy rather than differences in the optical and neural properties of the visual system.     

Wire-bending test as a predictor of preclinical performance by dental students

Traditional Dental Aptitude Test and academic grade point average have been shown to be poor predictors of clinical performance by dental students. To refine predictors of psychomotor skills, a wire-bending test was given to 105 freshmen at the beginning of their dental education. Grades from seven restorative preclinical courses in their freshman and sophomore years were compared to scores on wire bending and the three traditional predictors: GPA, academic aptitude, and perceptual aptitude scores. Wire-bending scores correlated significantly with six out of seven preclinical restorative courses. The predictive power for preclinical performance was doubled when wire bending was added to traditional predictors in stepwise multiple regression analysis. Wire-bending scores identified students of low performance. These preliminary results suggest that the wire-bending test shows some potential as a screening test for identifying students who may hae psychomotor difficulties, early in their dental education.     

Insulin and dextrose effects on fixed-interval behavioral thermoregulation in albino rats

This study is a systematic replication of the effects of insulin doses on operant behavior reinforced (in an earlier study) by fixed-ratio schedules of microwave (MW) reinforcement. In this study, insulin and dextrose doses were administered (ip) prior to fixed-interval 2-min. schedules of MW reinforcement in rats tested in a cold environment. Six Sprague-Dawley rats were conditioned to regulate their thermal environment with 5-sec. exposures of MW radiation (SAR = 0.34 Watts/kg/(mW/cm2) under the FI-2' schedules. Humulin-regular insulin and 50% solutions of dextrose were administered (ip) alternately with saline control sessions for 8-hr. durations. A within-subjects, repeated-measures 4 x 8 x 3 factorial analysis of variance design showed that insulin doses suppressed operant responding for heat, which confirmed the results of the earlier study under a different schedule. In addition, high doses of dextrose had similar suppressing effects on operant responding for heat. The data are interpreted in terms of the discriminative properties of increased thermogenesis produced by the insulin and dextrose doses. The suppressing effects were more pronounced for the first two hours, yet they persisted for approximately six hours of the 8-hr. sessions.     

RELIABILITY AND VALIDITY OF IN-BASKET PERFORMANCE MEASURES

The in-basket test is a frequently used assessment tool for predicting job performance and, to a lesser extent, as a technique for research and development in various human resource applications. While the in-basket test has obvious attractive features for application in the business setting, there is a great degree of uniqueness in each application and relatively little research focusing on critical issues involved in construction or evaluation. In this paper, the literature focusing on the psychometric properties of in-basket measures of performance are reviewed and evaluated. The compiled evidence provides only modest support of the usefulness of the in-basket test as a measurement tool.     

SCALING PERFORMANCE UTILITY TO ENHANCE SELECTION/CLASSIFICATION DECISIONS

For purposes of selection and classification there are two general reasons for scaling the mean and variance of the utility of performance across jobs. First, if differential utility across jobs does exist, then the payoff from a selection and classification system will be enhanced to the extent that accurate utility values are incorporated in the assignment system. Second, a valid utility metric would permit a more meaningful comparison of the gains achieved by alternative selection and classification procedures. It is argued in this paper that the Army context, and perhaps others, precludes using the dollar metric and estimates of SD_y in dollars. Consequently, Project A conducted a relatively long series of exploratory workshops with Army personnel to (a) define the utility issue, (b) pilot test a wide variety of possible scaling methods, and (c) evaluate the methods that seemed most appropriate. On the basis of exploratory analysis, a combined procedure incorporating both an interval estimation and a ratio estimation method was used to estimate the utility of five different performance levels for each of 276 jobs (MOS) in the enlisted personnel system. The psychometric properties of the resulting scale values are analyzed and discussed.     

MODELING JOB PERFORMANCE IN A POPULATION OF JOBS

The Army Selection and Classification Project has produced a comprehensive examination of job performance in 19 entry-level Army jobs (Military Occupational Specialties) sampled from the existing population of entry-level positions. Multiple methods of job analysis and criterion measurement were utilized in a subsample of nine jobs to generate over 200 performance indicators, which were then used to assess performance in a combined sample of 9,430 job incumbents. An iterative procedure involving a series of content analyses and principal components analyses was used to develop a basic array of up to 32 criterion scores for each job. This basic set of scores formed the starting point of an attempt to model the latent structure of performance in this population of jobs. After alternative models were proposed for the latent structure, the models were submitted to a goodness-of-fit test via LIS-REL VI. After accounting for two components of method variance, a five-factor solution was judged as the best fit. The implications of the results and the modeling procedure for future personnel research are discussed.     

Automaticity in spelling competence

Two studies examined the speed with which good spellers and poor spellers spell easy and difficult words. At both the elementary school (Grades 3 and 4) and undergraduate levels, good spellers spelled words more quickly than poor spellers. This difference appeared even for very easy words that all subjects could spell. Implications for the importance of automaticity in spelling competence are discussed.