MMPI characteristics of drug abusers with and without histories of suicide attempts

Compared to drug addicts without histories of suicidal attempt (n = 50), drug addicts who have attempted suicide (n = 50) were characterized by higher levels of maladjustment--particularly in the areas of depression, feelings of alienation, and use of projection and externalization--and were more emotionally withdrawn. Certain Minnesota Multiphasic Personality Inventory (MMPI) codetypes appeared in the attempt group that were not present in the no history group. Drug addicts with suicidal ideation but no history of attempt (n = 13) were not significantly different from the other two groups, and their inclusion as a comparison group masked the real differences between the other two groups. The MMPI results suggest it may be possible to identify a suicide attempt group in substance abusers but not when contrasted with a suicidal ideation group. Treatment implications are considered.     

Differential reinforcement and signal detection.

Reinforcement was introduced for responses normally treated as errors in signal-detection procedures. The first experiment used a standard two-response discrete-trial procedure with no reinforcement for errors. Results showed that rats altered their response biases but maintained constant sensitivity to visual signals when reinforcement probabilities varied, and that their sensitivity depended on the physical difference between signals, in accordance with the predictions of signal-detection theory. Experiment II, with rats, and Experiment III, with pigeons, demonstrated that sensitivity decreased in this procedure when reinforcement was scheduled for errors with the signals held constant, despite independence of overall number of reinforcers and sensitivity. Experiment IV, with rats, replicated the decrease in sensitivity in a continuous procedure employing only one response. The decrements in sensitivity were similar across Experiments II, III, and IV, and accorded well with earlier research. Thus, contrary to a fundamental assumption of signal-detection theory, estimates of sensitivity are not always invariant with respect to the outcomes of responding, but depend on relative reinforcement of correct responses.     

Allocation of attention and the locus of adaptation to displaced vision.

Experimental subjects were exposed to prism-induced visual displacement of a target whose location was correctly given by proprioceptive-kinesthetic information. Control subjects were exposed alternately to visual displacement or proprioceptive-kinesthetic location information. During the adaptation period, experimental subjects in the visual attention condition performed a localization task that directed them to attend selectively to the visual modality; experimental subjects in the proprioceptive attention condition attended selectively to the proprioceptive modaltiy; control subjects performed the task on the basis of the available modality. Measures of adaptation and aftereffect were secured separately in each of the two modalities. These confirmed the predictions that the shifts in the experimental conditions would be confirmed to localization tests dependent on the unattended modality and that control subjects would not exhibit adaptation. We proposed that allocation of attention determines situational dominance and that dominance determines the locus of adaptation. The findings were compared to those reported by Canon (1970) and were applied to a reassessment of the "visual capture" phenomenon.     

A new look at selective exposure

The relevance of the personality dimension “repression-sensitization” (D. Byrne in B. A. Maher (Ed.), Progress in experimental personality research, Vol. 1, NY: Academic Press, 1964, pp. 169–219) to selective exposure processes was investigated. Experimental repressors (who typically employ “avoidance” strategies in dealing with threatening stimuli) and experimental sensitizers (who generally “approach” threatening stimuli) were allowed to choose and keep one of two pairs of painting reproductions, each pair containing one positively and one negatively valued painting. After the decision, which experimental subjects believed terminated the experiment, subjects were allowed to inspect the alternatives ad libitum for 75 sec. Eye gaze during this period was unobtrusively videotaped. Compared to their matched controls, who were simply asked to inspect the paintings in order to decide which ones they liked best, experimental repressors inspected paintings that were consonant with their choices and avoided looking at paintings that were dissonant with their decisions. Experimental sensitizers did not manifest such postdecisional selective exposure. The implications of these results for past and future research on dissonance-produced selective exposure were discussed.     

Recall of semantic domains

The order of recall of lists of words learned incidentally was analyzed by multidimensional scaling similarity matrices based on the number of times words were retrieved next to each other. For the semantic domains of mammals, birds, and kinship terms, retrieval from very long-term memory, both for groups and individuals, and recall of recently learned lists produced multidimensional solutions similar to published solutions based on judged relatedness and associative overlap. For the squares of the Monopoly board and the names of the members of the Lawrence University faculty, for which clear a priori category structures exist, the form of clustering in the order and timing of recall that is commonly found in recall of lists learned recently in the laboratory was also found in the retrieval of lists learned incidentally through multiple exposures over long periods of time in the real world.     

Reinforced variability and operant learning

Reinforcement of variability may help to explain operant learning. Three groups of rats were reinforced, in different phases, whenever the following target sequences of left (L) and right (R) lever presses occurred: LR, RLL, LLR, RRLR, RLLRL, and in Experiment 2, LLRRL. One group (variability [VAR]) was concurrently reinforced once per minute for sequence variations, a second group also once per minute but independently of variations, that is, for any sequences (ANY), and a control group (CON) received no additional reinforcers. The 3 groups learned the easiest targets equally. For the most difficult targets, CON animals' responding extinguished whereas both VAR and ANY responded at high rates. Only the VAR animals learned, however. Thus, concurrent reinforcers--contingent on variability or not--helped to maintain responding when difficult sequences were reinforced, but learning those sequences depended on reinforcement of variations.     

Individual differences in gains from computer-assisted remedial reading

Two hundred second- to fifth-grade students (aged approximately 7 to 11 years) spent 29 h in a computer-assisted remedial reading program that compared benefits from accurate, speech-supported reading in context, with and without explicit phonological training. Children in the "accurate-reading-in-context" condition spent 22 individualized computer hours reading stories and 7 small-group hours learning comprehension strategies. Children in the "phonological-analysis" condition learned phonological strategies in 7 small-group hours, and divided their computer time between phonological exercises and story reading. Phonologically trained children gained more in phonological skills and untimed word reading; children with more contextual reading gained more in time-limited word reading. Lower level readers gained more, and benefited more from phonological training, than higher level readers. In follow-up testing, most children maintained or improved their levels, but not their rates, of training gains. Phonologically trained children scored higher on phonological decoding, but children in both conditions scored equivalently on word reading.