Considerations in the use of difference scores to identify learning-disabled children

Although difference scores are widely used in classifying children as learning-disabled, their psychometric properties are often not well understood. Such scores generally contain more error than single test scores. Reliability and standard error of measurement figures for several combinations of ability and achievement measures are presented. The rates and types of errors that occur when such scores are used to classify children as learning-disabled are discussed. Three recommendations for using difference scores are given: (a) combinations of ability and achievement tests that yield difference score reliabilities higher than .80 should be used when classifying children; (b) scores should be reported as a band of scores (± one standard error of measurement) to inform decision-makers regarding the amount of error estimated to be in the score, and (c) the criterion score for classifying the learning disabled should be set after consideration of the rate and types of errors likely to occur.     

BUILDING RESPONSE CLASSES: A COMPARISON OF TWO PROCEDURES FOR TEACHING GENERALIZED POURING TO LEARNERS WITH SEVERE DISABILITIES

Five individuals with profound mental retardation received instruction on liquid pouring. The effects of two training strategies on performance with nontrained pitchers and receptacles were compared within a split multiple baseline design across subjects. One training approach followed general case instruction guidelines in which both difficult and easy teaching examples were selected that sampled the range of relevant stimulus and response variation. The second training approach approximated the early steps in an easy-to-hard sequencing strategy and involved using only a set of easy teaching examples that did not sample the full range of relevant stimulus and response variation required for successful pouring in natural settings. Results indicated that only after training with the full set of general case examples did the learners become competent with the nontrained generalization probe tasks. In addition, the set of easy examples resulted in learners performing topographically predictable errors with the generalization probe tasks.     

Primacy of dimensions in vibrotactile perception: an evaluation of early holistic models.

Early holistic models of perception presume that stimuli composed of interacting dimensions can be experienced initially as undifferentiated. This view, formalized through recourse to a Euclidean geometry of perceptual space, predicts that the orientation of axes used to create stimulus sets is unimportant to performance in speeded classification. We tested this idea by using the interacting vibrotactile dimensions of pitch and loudness. Despite perceivers' relatively poor experience with these dimensions, we showed that the orientation corresponding to pitch and loudness was unique in vibrotactile perceptual space; subjects classified stimuli more efficiently at this orientation than at other orientations. Certain holistic models also claim that when stimulus differences are small, perceivers can recognize change without distinguishing the kind of change. We tested this idea by using a signal detection analysis of unspeeded same-different decisions. We found that subjects' ability to notice the kind of change equaled their ability to notice the change alone. In view of these results, which indicate that pitch and loudness are primary in vibrotactile perception, we detail a new conception of dimensional interaction.     

Spatial-frequency-contingent color aftereffects: adaptation with two-dimensional stimulus patterns.

The spatial-frequency theory of vision has been supported by adaptation studies using checkerboards in which contingent color aftereffects (CAEs) were produced at fundamental frequencies oriented at 45 degrees to the edges. A replication of this study failed to produce CAEs at the orientation of either the edges or the fundamentals. Using a computer-generated display, no CAEs were produced by adaptation of a square or an oblique checkerboard. But when one type of checkerboard (4 cpd) was adapted alone, CAEs were produced on the adapted checkerboard and on sine-wave gratings aligned with the fundamental and third harmonics of the checkerboard spectrum. Adaptation of a coarser checkerboard (0.80 cpd) produced CAEs aligned with both the edges and the harmonic frequencies. With checkerboards of both frequencies, CAEs were also found on the other type of checkerboard that had not been adapted. This observation raises problems for any edge-detector theory of vision, because there was no adaptation to edges. It was concluded that spatial-frequency mechanisms are operating at both low- and high-spatial frequencies and that an edge mechanism is operative at lower frequencies. The implications of these results are assessed for other theories of spatial vision.     

Counselling for women: The contribution of feminist theory and practice

Much of the literature on the theory and practice of counselling is gender-blind, the assumption being that the emotional worlds of women and men are the same. This view is challenged, the author reviewing the work of feminist theorists and practitioners. Central to this discourse is the argument that to understand the internal psychic structures of women, her concepts of se& we have to acknowledge the effect of external and oppressive structures on her psychological development. This can assist us in our understanding of how the therapeutic relationship might address women's needs and provide the ‘space’ for her to grow and change.     

Spatial-frequency-contingent color aftereffects: Adaptation with one-dimensional stimuli

The McCollough effect was shown to be spatial-frequency selective by Lovegrove and Over (1972) after adaptation with vertical colored square-wave gratings separated by 1 octave. Adaptation with slide-presented red and green vertical square-wave gratings separated by 1 octave failed to produce contingent color aftereffects (CAEs).However, when each of these gratings was adapted alone, strong CAEs were produced. Adaptation with vertical colored sine-wave gratings separated by 1 octave also failed to produce CAEs, but strong effects were produced by adaptation with each grating alone. By varying the spatial frequency of the test sine wave, CAEs were found to be tuned for spatial frequency at 2.85 octaves after adaptation of 4 cycles per degree (cpd) and at 2.30 octaves after adaptation of 8 cpd. Adaptation of both vertical and horizontal sine-wave gratings produced strong CAEs, with bandwidths ranging from 1.96 to 2.90 octaves and with lower adapting contrast producing weaker CAEs. These results indicate that the McCollough effect is more broadly tuned for spatial frequency than are simple adaptation effects.     

Examination of supervisory satisfaction in traditional and nontraditional gender-based reporting relationships

Supervisory Satisfaction relates to satisfaction with supervision rather than other conditions or agents in the work place. The supervisor-subordinate relationship is becoming increasingly important given the shift from managing work to managing people. Six variables were theorized as influencing satisfaction. Developing a parsimonious model to predict the variance in supervisor satisfaction, this empirical study examined 202 traditional supervisory relationships (subordinate reporting to a male supervisor) and 48 nontraditional supervisory relationships (subordinates reporting to a female supervisor). The sample was predominantly whites. Four of the five variables theorized, predicted a high level of variance in supervisory satisfaction in both traditional and nontraditional relationships. However the predictors were not different for the two groups.