Validity of psychologists' identification of EMR students in the perspective of the California decertification experience

The Diana (Diana v. State Board of Education, Note 1) and the Larry P. (Larry P. v. Riles, Note 2) litigations led to decertification of thousands of California EMR students and their return to the regular program. Allegations, including those of biased testing, went largely uncontested in order that change in special education could result from court mandate, but the allegations left the psychologists in a libeled state. A study of cumulative records and psychologists files in 12 representative districts permitted a comparison of the EMR placement of those later decertified (D) with matched nondecertified (EMR). Other than a small mean difference in IQ at placement, nothing was found to support various allegations. Records showed no systematic differences betweeen D and EMR groups in pre-EMR reasons for referral nor in teacher marks, discnfirming beliefs in referral of higher functioning students for deportment rather than for academic failure. Districts permitted a mean of at least two years in regular placement before assessment, attesting to class failure rather than IQ as the initial and necessary basis for EMR identification (no D-EMR difference in this either). The data permit a conclusion that the work of the school psychologists in the EMR placement was professionally competent, given the guidelines in effect at the time.     

Relative costs and statistical power in the extreme groups approach

The relationship between variables in applied and experimental research is often investigated by the use of extreme (i.e., upper and lower) groups. Recent analytical work has provided an extreme groups procedure that is more powerful than the standard correlational approach for all values of the correlation and extreme group size. The present article provides procedures to optimize power by determining the relative number of subjects to use in each of two stages of data collection given a fixed testing budget.The opinions or assertions contained herein are those of the writers and are not to be construed as official or reflecting the views of the Navy Department.Edward F. Alf, Jr. is also affiliated with the Department of Psychology, San Diego State University.     

Isolating the typicality effect in semantic memory

An experiment was conducted to isolate the typicality effect in the overall categorization process. Subjects were required to indicate whether or not a probe word was a member of one of a variable number of categories held in memory. The typicality of the probe word, with respect to its superordinate category, was varied as was the physical quality of the probe. These manipulations were designed to test predictions drawn from Collins and Loftus (1975) and Anderson and Reder (1974), as well as a prediction based on the well-known effect of semantic context on word perception. A fourth prediction was drawn from a proposed model which postulates successive access of categories and locates the typicality effect in a within-category search stage. Typicality proved to be additive with stimulus quality and set size, but interacted with response type. These results were interpreted as support for the successive-access within-category search model while disconfirming the alternative predictions.     

Age comparative factor analysis of ability variables in adulthood and old age

The generality of ability factor structure in adulthood and old age was investigated using simultaneous maximum likelihood procedures. Data were analyzed for 198 young individuals (age range of 15–32 years), 156 younger old individuals (age range of 53–68 years), and 156 older old individuals (69–91 years). Variables were nine tests marking three ability factors: Verbal Comprehension, Sensitivity to Problems and Semantic Redefinition. Results indicated no changes in the number of factors and no psychologically important shifts in salient factor loadings. Increasingly larger factor covariances, however, were obtained in the two older groups. The results supported the generalizability of ability structures to late life at the level of factor loadings. The implications of these results for the dedifferentiation hypothesis were not clear cut. The consistency of the number of factors across age groups precluded strong support for this hypothesis, The increased factor covariances could be construed as modest support for this hypothesis, but other interpretations were possible.     

The sensing of retinal motion

The apparent relative motion of physically stationary objects that frequently occurs as the head is moved in a frontoparallel plane is almost always in the direction expected from the projection into the distal world of the relative motion of the images on the eye. It is hypothesized that this is the result of the perceptual underestimation of the depth between the objects. If a perceptual overestimation of the depth were produced, it was predicted that the apparent relative motion would be in a direction opposite to that expected from the projection of the retinal motions. This prediction was tested using the binocular disparity cue to produce perceptual overestimation of the slant (depth) of a luminous line. In this case, perceived slant was the indicator of perceived depth, and perceived rotation concomitant with the motion of the head was the indicator of perceived relative motion. The results support the prediction and also provide some support for a theoretically derived equation specifying the relation between these two perceptual variables.     

Distributed study facilitates infants’ delayed recognition memory

Infants of 5–6 months of age were tested for recognition of briefly presented photographs of faces. The interaction typically obtained with adults, a beneficial effect on retention due to the temporal spacing of study, was obtained with these infants. The results suggest that the distribution effect reflects a fundamental and automatic process of human memory.