Structural alterations of an ambiguous musical figure: The scale illusion revisited

The scale illusion (Deutsch, 1975) shows the importance of frequency range in the perceptual organization of a sequence of notes. This paper includes three experiments on the scale illusion. Experiments 1 and 2 demonstrated that if the structure of the pattern of notes used in the original scale illusion study is altered slightly, by adding or subtracting a pair of notes from the ends of the sequence, there is a significant decrease in the rate of frequency-based responses, suggesting a weaker illusion. Experiment 3 investigated two features of the note patterns that may have led to this change. Specifically, it asked whether the decrease in the strength of the illusion is due to (1) the nature of the notes at the extremes of the frequency range and/or (2) the nature of the notes at the crossing point of the two scales. While both sources were found to affect the strength of the scale illusion, the former had a greater influence.     

Comparing one-step m-estimators of location corresponding to two independent groups

Experience with real data indicates that psychometric measures often have heavy-tailed distributions. This is known to be a serious problem when comparing the means of two independent groups because heavy-tailed distributions can have a serious effect on power. Another problem that is common in some areas is outliers. This paper suggests an approach to these problems based on the one-step M-estimator of location. Simulations indicate that the new procedure provides very good control over the probability of a Type I error even when distributions are skewed, have different shapes, and the variances are unequal. Moreover, the new procedure has considerably more power than Welch's method when distributions have heavy tails, and it compares well to Yuen's method for comparing trimmed means. Wilcox's median procedure has about the same power as the proposed procedure, but Wilcox's method is based on a statistic that has a finite sample breakdown point of only 1/n, wheren is the sample size. Comments on other methods for comparing groups are also included.     

Comparing examinees to a control

When comparing examinees to a control, the examiner usually does not know the probability of correctly classifying the examinees based on the number of items used and the number of examinees tested. Using ranking and selection techniques, a general framework is described for deriving a lower bound on this probability. We illustrate how these techniques can be applied to the binomial error model. New exact results are given for normal populations having unknown and unequal variances.The work upon which this publication is based was performed pursuant to a grant [Grant No. NIE-G-76-0083] with the National Institute of Education, Department of Health, Education and Welfare. Points of view or opinions stated do not necessarily represent official NIE position or policy.     

Autoshaping of abnormal children

Three experimentally naive abnormal children were exposed to a terminal operant contingency, i.e., reinforcement was delivered only if the children pressed a panel during intervals when it was lighted. Despite the absence of both successive approximation and manual shaping, it was found that each child began to respond discriminatively within a small number of trials. These data replicated previous animal studies concerned with the phenomena of autoshaping and signal-controlled responding. It was also found, however, that one type of autoshaping, the classical conditioning procedure, had a powerful suppressive effect on discriminative responding. An experimental analysis that consisted of a combination of intrasubject reversal and multiple baseline designs established the internal validity of the findings. The finding of rapid acquisiton of signalcontrolled responding obtained with the initial procedure is suggested to have practical significance. The disruptive effects of the classical form of autoshaping are discussed in terms of negative behavioral contrast.Funding for this study and for the development of the computer-operated laboratory was provided by the USOE, Bureau of Education for the Handicapped, as a portion of Grant Number G007604305, sensory discrimination, generalization, and language training of autistic children, awarded to R. L. Blanton and C. W. Deckner. The authors would like to express their appreciation to John Halsell for his assistance in computer operations and data collection.     

Spatial and temporal properties of stereoscopic surface interpolation

It is well established that under a wide range of conditions when a sparse collection of texture elements varies smoothly in depth, the spaces between the elements are assigned depth values. This disparity interpolation process has been studied in an effort to define some of its fundamental spatial and temporal constraints. To assess disparity interpolation we employed two tasks: a novel task that relies on the bisection of illusory boundaries created when subjective stereoscopic surfaces intersect, and one that relies on a 3-D shape discrimination. The results of both experiments show that there is no improvement in performance when texture density is increased from near 0.20 to 0.85 or when exposure duration is increased from 50-100 to 1000 ms. This lack of dependence on the addition of features that define the interpolated surface, along with the abrupt decline in performance below a critical value, is consistent with the view that surface interpolation is an important function of human stereoscopic vision.     

The Origins of Hopelessness Among Inner-City African-American Adolescents

Much has been written in recent years about hopelessness among residents of impoverished inner-city neighborhoods, but little research has been conducted on the origins of hopelessness. The literature on social disorganization and the literature on child development independently suggest two possible causes of hopelessness among adolescents: disruptive events and lack of connectedness to people and institutions. We explore these two factors as predictors of hopelessness for 5895 youths living in impoverished inner-city neighborhoods in Mobile, Alabama. The longitudinal data for this study allow us to explore the development of hopelessness over time, predicted by prior levels of disruption and connectedness. The results show that over time several variables associated with disruption (Change in Mother Figure, Exposure to Violence, Traumatic Stress, Worry) and connectedness (Sense of Community, Warmth Toward Mother, Religiosity) are positively or negatively associated with increased feelings of hopelessness among inner-city adolescents.     

Violence and sex in television programs do not sell products in advertisements

Adults (N = 336) 18 to 54 years old watched a television program containing violence, sex, both violence and sex, or no violence and sex. Programs were shown in a comfortable room containing padded chairs and tasty snacks. Each program contained the same 12 ads. Embedding an ad in a program containing violence or sex reduced (a) viewers' likelihood of remembering the advertised brand, (b) their interest in buying that brand, and (c) their likelihood of selecting a coupon for that brand. These effects occurred for males and females of all ages, regardless of whether they liked programs containing violence and sex. These results show that violence and sex in television programs do not sell products in advertisements.