Apparatus conceptualization for psychopathological research inmonkeys

Investigation of psychopathology in monkeys requires analysis of multiple variables mediating specific behaviors. Assessment of both the relative contribution of each variable and the interactions among them is facilitated by the use of apparatuses whose designs permit separate or simultaneous manipulation of several variables. Three such devices, the pit, the tunnel of terror, and the standard living-experimental cage, each specifically constructed for the production of depression or despair in monkeys, are described.     

Anchor effects using numerical estimates of simple dot patterns

Shifts due to anchor stimuli using absolute judgments have been ascribed to “semantic” and “scale modulus” changes. To test this explanation, random dot patterns of 10, 12, 14, 16 and 18 dots were exposed for 0.30 sec with anchors of 4, 13 or 32 dots preceding each of the stimuli. In the control only the series of stimuli were judged. It was found that numerical estimates of the number of dots increased with small anchor, decreased with large anchor, and were not significantly changed with anchor in the vicinity of AL. These results exactly parallel those found using methods of absolute and comparative ratings and hence cannot be ascribed to semantic shifts especially in view of the fact that independent groups of Ss served in the four anchor and control conditions. Since the anchor effects were significant but not so large that they can be ascribed to change of scale modulus this theory must also be rejected. The AL model seems to offer the simplest and most unitary explanation of these as well as many other results obtained with different types of stimuli and different methods of judging.     

Resolution of the heywood case in the minres solution

In the course of developing the minres method of factor analysis the troublesome situation of communalities greater than one arose. This problem—referred to as the generalized Heywood case—is resolved in this paper by means of a process of minimizing the sum of squares of off-diagonal residuals. The resulting solution is superior to the otherwise very efficient original minres method without requiring additional computing time.Both authors were with the System Development Corporation when this work was done.     

A correction for replicated error in correlation coefficients

A solution is presented to the problem of determining a proper correction for spuriousness in correlation coefficients. The general case developed is the estimate of correlation betweenu andv, both being linear functions of the same set of variables. Special formulae relate to overlapping scales correlations, part-whole correlations, and item-total test correlations.The research and development reported herein was performed pursuant to a contract with the United States Department of Health, Education, and Welfare, Office of Education, under the provisions of the Cooperative Research Program. This research was conducted by the Evaluation Division of the Research and Development Center in Educational Stimulation. The authors wish to thank E. E. Cureton for his helpful suggestions.     

Different thresholds for recognition—further experiments on interpolated recall and recognition

Three experiments are described which have attempted to identify some of the difficulties in recognition after interpolated recall. In the first, complex picture material was used, and, though subjects were able to recognize the original after interpolated recall, they did in fact recognize fewer items. This posed the query, why should the recall of some items depress the recognition of other unrecalled items? The second experiment showed that in recognition the stronger (correct) memory has an inhibitory effect on a weaker (also correct) memory. The third experiment therefore examined the hypothesis that the juxtaposition of better and worse known items raises the threshold of recognition of the worse known, and confirmed that the threshold of recognition for an item varies according to its context. The theoretical significance of this finding is briefly indicated.