Effects of discrimination training on responding during a compound conditioned stimulus.

Four experiments examined responding in the presence of a triple-element compound ABC after discrimination training in which 2 compounds, AB and BC, signaled the delivery of food and 1 element alone, B, signaled the absence of food. In Experiments 1 and 2, using rats, responding during ABC was more vigorous than in a control group for which A and C but not B had been individually paired with food. This finding was replicated in Experiment 3, which used pigeons, and in Experiment 4, where all 3 stimuli of the control condition were individually paired with food. The results are more consistent with a configural than with an elemental theory of learning.     

Testing for spontaneous use of requests after sign language training with two severely handicapped adults

A variety of procedures have been used to promote spontaneous requesting in persons with developmental disabilities. However, effective use of such procedures depends in part on identifying the stimuli that gained control of requests during intervention. In the present study, two adults with severe disabilities were taught to request a preferred food item with a modified gesture for “eat.” After learning to respond when the trainer held up an item, an assessment of stimulus control was conducted to determine if requests would occur spontaneously, that is, without the trainer having to offer the item. One learner displayed a number of spontaneous requests during the assessment. Natural maintaining contingencies were then introduced to maintain his spontaneous requests. The other learner made no spontaneous requests during the initial assessment, but subsequent tests revealed that he sometimes requested as the trainer was about to display the item. It thus appeared that both learners were responding at an earlier point in the trial sequence. The results suggest that an assessment of stimulus control may be helpful when selecting strategies to promote spontaneous requesting.     

Rasch models for item bundles

This paper discusses the application of a class of Rasch models to situations where test items are grouped into subsets and the common attributes of items within these subsets brings into question the usual assumption of conditional independence. The models are all expressed as particular cases of the random coefficients multinomial logit model developed by Adams and Wilson. This formulation allows a very flexible approach to the specification of alternative models, and makes model testing particularly straightforward. The use of the models is illustrated using item bundles constructed in the framework of the SOLO taxonomy of Biggs and Collis.The work of both authors was supported by fellowships from the National Academy of Education Spencer Fellowship.     

Testing alternative explanations for mortality salience effects: Terror management,value accessibility,or worrisome thoughts?

Previous research has shown that reminding subjects of their mortality encourages negative reactions to others whose behaviour or attitudes deviate from the cultural worldview (e.g. Greenberg, Pyszczynski, Solomon, Rosenblatt, Veeder, Kirkland and Lyon 1990; Greenberg, Simon, Pyszczynski, Solomon and Chatel 1992; Rosenblatt, Greenberg, Solomon, Pyszczynski and Lyon 1989). According to terror management theory, these findings result from a heightened need for faith in the cultural worldview that is activated by reminders of one's mortality. Study I assessed the plausibility of an alternative explanation which posits that mortality salience simply primes individuals' values. Whereas mortality salience led to harsher bond recommendations for a prostitute, a procedure that directly focused subjects on their values did not. Studies 2 and 3 assessed the possibility that reminding subjects of any worrisome future concern would produce the same effect as a reminder of mortality. In both studies, mortality salience led to negative reactions to a deviant and had no effect on self-reported affect, whereas other worrisome thoughts had no effect on reactions to a deviant but did create negative affect. Thus, consistent with terror management theory, mortality salience effects seem to result exclusively from thoughts of death.     

Once more to dissolve the ravens

W. E. Johnson argued that by taking into account both the epistemic and constitutive conditions for using arguments in inferences one could dissolve the paradoxes of material implication. This essay argues that the same sort of consideration can be used to dissolve the paradox of ravens in confirmation theory. It is argued in particular, and in agreement with certain points raised by the Popperians, that those instances of a generalization which are verifying but apparently not confirming cannot raise the posterior of that generalization.     

A factor-analytic study of creative-thinking abilities

Fifty-three tests designed to measure aspects of creative thinking were administered to 410 air cadets and student officers. The scores were intercorrelated and 16 factors were extracted. Orthogonal rotations resulted in 14 identifiable factors, a doublet, and a residual. Nine previously identified factors were:verbal comprehension, numerical facility, perceptual speed, visualization, general reasoning, word fluency, associational fluency, ideational fluency, and a factor combining Thurstone'sclosure I andII. Five new factors were identified asoriginality, redefinition, adaptive flexibility, spontaneous flexibility, andsensitivity to problems.Under Contract N6onr-23810 with the Office of Naval Research. The opinions expressed are our own and are not necessarily shared by the Office of Naval Research. These studies are under the direction of J. P. Guilford. Paul R. Christensen is assistant director. Robert C. Wilson has been principally responsible for the conduct of this particular study. Donald J. Lewis contributed to the development of hypotheses and tests. Raymond M. Berger made substantial contributions to the development of the tests.The authors are very much indebted to the Personnel Research Laboratory, Human Resources Research Center, Air Training Command, Lackland Air Force Base, Texas, for making the testing possible, and in particular to Dr. Lloyd G. Humphreys, Director, and to Mr. William B. Lecznar, Technical Aide.Acknowledgement is made to Gordon Taaffe for the supervision of much of the statistical work connected with this study and to Norman W. Kettner for carrying out the extractions of factors and for valuable assistance on the rotations of axes.A fuller discussion of this factor analysis is given by Wilson (16).     

The variance of the number of mutual choices in sociometry

The variance of the number of mutual dyads in a sociometric situation where each member of a group chooses independently and at random is derived for unrestricted numbers of choices per group member, as well as for a fixed number of choices. The distribution of the number of mutuals is considered.We are indebted to Robert Bush and Hartley Rodgers of Harvard University for helpful criticisms.     

Configural associations in discrimination learning

In 4 experiments, Sprague-Dawley rats and homing pigeons received training with an A+ AB0 BC+ discrimination, in which food (+) accompanied trials with A and BC. Food was not presented (0) on trials with the compound AB. Subsequent test trials revealed that responding during C by itself, or the compound ABC, was slower than during either A or BC. Responding during the ABC compound was also found to be slower after training with the A+ AB0 BC+ than an A0 AB+ BC+ discrimination. We argue that these findings demonstrate the importance of configural associations in discrimination learning. Two accounts for the way in which these associations exert their influence are considered.