Positive contrast following gradual and abrupt increases in reward magnitude using delay of reinforcement

In Experiment 1, rats were given a 1-pellet reward for 48 preshift trials. During a subsequent 20-trial postshift phase, one group was shifted to a 12-pellet reward on Trial 1, a second was shifted on Trial 11, and a third was given 1 more pellet each trial and then 12 pellets for the last 10 trials. The speeds of all three groups increased to a level above that of a control group given a 12-pellet food reward throughout training (positive contrast). In experiment 2, rats were shifted from 1 to 12 pellets either gradually or abruptly following either abbreviated training (9 trials) or extended training (20 trials). One group of control subjects received 12 pellets throughout training. The results revealed a positive contrast effect for gradually shifted subjects following extended training but not following abbreviated training. The abrupt shift procedure produced positive contrast following abbreviated training but only a marginal effect following extended training. These results indicate that, contingent upon the amount of preshift training, either gradual or abrupt reward increases may produce positive contrast.     

Recognition memory for words and pictures at short and long retention intervals

In two experiments, subjects studied a long series of words and pictures for recognition. Retention intervals varied from several minutes to a few months. The complicated testing procedures in Experiment I required the use of a traditional correction for guessing to obtain estimates of subjects' memory performance. A comparable, but simpler, design in Experiment II permitted the calculation of sensitivity and bias measures. In both studies, pictorial memory was superior to verbal memory at all retention intervals tested, and this advantage was essentially constant over time. In addition, the experiments identified an increasing tendency to call verbal test items "old" over time. Bias scores in Experiment H revealed that subjects adopted a more lenient criterion in responding to words than to pictures, and increased leniency was noted for both item types over time. Explanations of the results are offered in terms of differences in initial encoding and of a loss of discrimination between experimental and extraexperimental materials.     

Some properties of the ego-resiliency subtle scale of the MMPI.

The Ego Resiliency-Subtle (ER-S) scale was developed by Block (1965) as a social desirability free measure of the first factor of the MMPI. The purpose of the present experiments was to determine whether or not the 40-items comprising the ER-S scale remain neutral regarding social desirability and if the subject's score on the scale remains constant when taken out of the context of the other MMPI items; if so, the ER-S scale could be used as a screening device. Experiment I demonstrated that the items were not neutral regarding social desirability when taken out of context, but Experiment II indicated that this did not influence the responses subjects gave to the items. Because a memory factor may have been operating in Experiment II, a third experiment was conducted to minimize this factor resulting in a male-female vs. embedded-alone interaction and an order of presentation vs. embedded-alone interaction.     

Component processes of an overt rehearsal strategy in young children

The locus of facilitation due to rehearsal was investigated in three experiments with first-grade children. Several different overt acquisition strategies in a four-item sequential memory task were compared, including ordered repetition, item repetition, item labeling, and free strategy conditions. Experiment 1 showed that ordered repetition yields most of the facilitation due to rehearsal, and Experiment 2 demonstrated that the facilitation cannot be attributed to spaced practice. Experiment 3 showed that retrieval practice during study may improve memory performance but that the facilitation due to ordered repetition and retrieval practice is relatively short term. Mere repetition and labeling were not found to be significant component processes of rehearsal in any of the experiments. These results were discussed in terms of their relevance to rehearsal training studies and a differentiation between maintenance and elaborative rehearsal.     

Syllabic vs segmental perception: On the inability to ignore “irrelevant” stimulus parameters

C. C. Wood and R S. Day have shown that reaction times (RT) to target segments within a syllable are significantly longer when the unattended segment in the syllable (either stop consonant or vowel) is varied randomly than when it is held constant. This has been taken as evidence for the perceptual unity of a stop con sonant-vowel syllable. However, this conclusion could be accepted with much more confidence if it could be shown that random variation in unattended segments does not cause an increase in RT if the unattended segments are not in the same syllable as the target segment. The present study, using bisyllabic natural speech stimuli, (1) reconfirms Wood and Day’s results, but (2) finds that random variation in unattended nontautosyllabic segments also results in significantly longer RTs than without nontautosyllabic variation. Segmental vs syllabic speech perception thus remains an open question.     

There's method in our madness: Interpersonal attraction as a multidimensional construct

The convergent validity and number of dimensions common to six measures of interpersonal attraction (three verbal and three nonverbal) were explored in this investigation. Convergent validity was found within verbal and nonverbal modes of measurement, but not between modes. No general factor was found to be common to the six measures of attraction. It was, therefore, concluded that method bias influences experimental results, threatening the comparability of results from research programs using different modes of measuring attraction. The results also question the assumption that social attitudes, such as attraction, are closely related to behavior, and imply that predictions derived from theories based on different modes of measuring attraction will have unequal utility.