The functional equivalence of problem solving skills

The tower of Hanoi problem is used to show that, even in simple problem environments, numerous distinct solution strategies are available, and different subjects may learn different strategies. Four major classes of solution strategies are described for the problem. Different strategies have different degrees of transferability, place different burdens on short-term memory and on perception, and require different learning processes for their acquisition. The analysis underscores the importance of subject-by-subject analysis of “what is learned” in understanding human behavior in problem-solving situations, and provides a technique for describing subjects' task performance programs in detail.     

Reinforcement from the sucking environment and subsequent modification of sucking behavior in the human neonate

The reinforcing aspects of sucking behavior in 36 human newborns was examined in a limited instrumental conditioning paradigm where sucking was both operant and reinforcer. During training, response density (rate based on sucking opportunity time) and latency were measures of two components of nonnutritive sucking, contingent negative pressure suction, and incidental jaw movement. The strategy for determining the reinforcing aspects of sucking involved comparisons of three types of sucking stimuli as reinforcers. The nature of modified operant sucking was investigated during extinction by examining number of sucks per burst, number of bursts emitted, and interburst interval time. The feedback from sucking which acted as reinforcement was concluded to be response density. Sucking was modified by changes in pausing behavior, including response latency and pauses between bursts of sucks. The number of sucks per burst also showed a significant change under certain conditioning arrangements.     

Modeling strategy shifts in a problem-solving task

A computer simulation model was fitted to human laboratory data for the Missionaries and Cannibals task to explain (1) the effects upon problem performance of giving a hint, and (2) the effects of solving the problem a second time after one successful solution had been achieved. Most of the variance in the relative frequencies of different moves can be explained by positing that the effect of the hint, or of previous experience in solving the problem, is to cause subjects to switch more promptly from a strategy of balancing the numbers of missionaries and cannibals on both sides of the river, to a means-ends strategy.     

On the relation between visual surround and motion aftereffect velocity

Two experiments examined the effect of changes in the visual surround upon the velocity of motion aftereffects. Experiment I showed that introduction or reintroduction of a patterned surround midway through the test period was sufficient to produce an increase in apparent velocity. However, a greater increase was observed when a patterned surround instead of a dark homogeneous surround had been used during the induction period. Experiment II demonstrated that luminance change was also sufficient to produce an increase in apparent velocity, although the extent of the increase was not as great as that produced through the use of the patterned surround in Experiment I. These results indicate that a change in stimulus surround is sufficient to produce an increase in the velocity of a motion aftereffect and that the extent of the increase is dependent upon the characteristics of both the induction and test surrounds.     

On the process of comparing sentences against pictures

The present study outlines a theory of how people compare sentences against pictures. This theory was tested in four experiments in which Ss were timed as they judged whether a sentence (e.g., Star isn't above plus) was true or false of a picture (e.g., ⁺_∗). The latencies in these tasks were consistent with the thesis that: (1) sentences are represented in terms of elementary propositions; (2) pictures are encoded in the same interpretive format; (3) these two codes are compared in an algorithmic series of mental operations, each of which contributes additively to the response latency; and (4) sentence encoding, picture encoding, comparing, and responding are four serially ordered stages, and their component latencies are additive. From these results, it was also possible to rule out certain explanations based on visual imagery, conversion (e.g., converting isn't above into is below), reading time, normative word frequencies, and other factors. Finally, it was shown that this theory is consistent with previous studies on sentence comprehension, sentence verification, concept verification, and other related phenomena.     

A comparative analysis of two community stressors' long-term mental health effects

The investigation directly compared the long-term mental health consequences of two community-wide stressors, the Three Mile Island (TMI) nuclear accident and widespread unemployment due to layoff, in demographically comparable samples of women. Results showed a marked degree of similarity in the stressors' effects: Levels of subclinical symptomatology were elevated to similar degrees in each sample during the year following stressor onset, and symptom levels remained elevated in each sample 2 to 3 1/2 years later. Moreover, variables identified as predictors of enduring psychological distress were virtually identical for the two samples. Additional analyses revealed that the mental health status of unemployed husbands mediated the negative psychological effects of layoff on their wives. Implications of these results for understanding the long-term consequences of exposure to community-wide stress are discussed.     

Replication of empirically derived syndromes as a basis for taxonomy of child/adolescent psychopathology

To advance the empirical identification of child/adolescent syndromes, principal components analyses were performed on four sets of parents' ratings of 8,194 6- to 16-year-olds referred to American and Dutch mental health services. The following syndromes replicated well for both sexes at ages 6-16: Aggressive, Anxious/Depressed, Attention Problems, Delinquent, Somatic Complaints, and Withdrawn. For both age ranges, a syndrome designated as Socially Inept replicated well among boys, and one designated as Mean replicated well among girls. Evidence was also found for a Schizoid syndrome in all sex/age groups and a Sex Problems syndrome among girls at ages 6-11. Syndrome scores discriminated well between nationwide normative and clinical samples. The replicated syndromes contribute to the empirical basis for a taxonomy of the kinds of disorders commonly seen between the ages of 6 and 16.     

Visual laterality effects: A signal detection analysis

Subjects were asked to indicate, by a simple motor response, the presence or absence of a pre-designated target letter in unilaterally presented consonant trigrams. For horizontally oriented stimuli (Experiment 1), perceptual sensitivity was greater in the right visual hemifield. For vertically oriented stimuli (Experiment 2), perceptual sensitivity did not differ between visual hemifields. Decision making was less conservative and reaction time was shorter with right hemifield presentation, regardless of stimulus orientation. Practice effects and serial position curves were examined. Implications of these results attribute laterality effects to iconic scanning patterns and to postperceptual decision processes.     

Tenacious inferential illusions: Experimental fact vs. critical fancy

Tzeng and Tzeng's (1982) assertion that the results from two indices of estimated item coendorsement should not have been combined in Mirels' (1976) demonstration of inferential illusions is shown to be based on erroneous suppositions. Evidence for the equivalence of the two formats makes it clear that the separate presentation of data for each index would have yielded results and led to conclusions virtually identical to those for the combined data. The objection by Tzeng and Tzeng to Mirels' use of empirical conditional probabilities as a criterion against which to assess the veridicality of Implicit Personality Theory is also shown to be without empirical foundation. In the light of available findings, the existence of striking inaccuracies in the culturally prevalent Implicit Personality Theory seems well established.