What is learned in sequential learning? An associative model of reward magnitude serial-pattern learning

A computational model of sequence learning is described that is based on pairwise associations and generalization. Simulations by the model predicted that rats should learn a long monotonic pattern of food quantities better than a nonmonotonic pattern, as predicted by rule-learning theory, and that they should learn a short nonmonotonic pattern with highly discriminable elements better than 1 with less discriminable elements, as predicted by interitem association theory. In 2 other studies, the model also simulated behavioral "rule generalization," "extrapolation," and associative transfer data motivated by both rule-learning and associative perspectives. Although these simulations do not rule out the possibility that rats can use rule induction to learn serial patterns, they show that a simple associative model can account for the classical behavioral studies implicating rule learning in reward magnitude serial-pattern learning.     

MMPI-A validity scale uses and limitations in detecting varying levels of random responding

Although there is a substantial research literature on the effects of random responding on the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), there are very few studies available on this topic with the MMPI-A (Butcher et al., 1992). Archer and Elkins (1999) found that MMPI-A validity scales F and VRIN were particularly useful in detecting entirely random profiles from those derived standardly in clinical settings but noted that "all random" protocols could not be used to evaluate the usefulness of the T-score difference between the first half (F1) and the second half (F2) of the MMPI-A test booklet. Following up on this issue, this study extended the methodology of previous research by examining the hit rate, positive predictive power, negative predictive power, sensitivity, and specificity of VRIN, F, F1, F2 and the absolute value of the T-score difference between F1 and F2 (denoted as IF1-F21) in 5 samples varying in the degree of protocol randomness. One of the samples consisted of 100 adolescent inpatients administered the MMPI-A under standard instructions, and another sample consisted of 100 protocols randomly generated by computer. The additional 3 samples of 100 protocols each contained varying degrees of computer-generated randomness introduced in the latter half of the MMPI-A item pool. Over- all, the results generally indicate that several MMPI-A validity scales are useful in detecting protocols that are largely random, but all of these validity scales are more limited in detecting partially random responding that involves less than half the total item pool located in the second half of the test booklet. Clinicians should be particularly cautious concerning validity inferences based on the observed T-score difference that occurs for the F1 and F2 subscales and current findings do not support the clinical usefulness of this index.     

A Rorschach study of oral dependence in alcoholics and depressives

Despite the strong association between alcoholism and orality in psychoanalytic theory, use of the Rorschach Inkblot Test to provide empirical support for such a link has yielded decidedly mixed results. However, Masling's Rorschach Oral-Dependency (ROD) scale has shown twice that people with alcoholism give more oral-dependent responses on the Rorschach than matched comparison groups (Bertrand & Masling, 1969; Weiss & Masling, 1970), which is supportive of classical analytic theory. In this study, we investigated alcohol groups, depression groups, and "normal" undergraduates with the ROD scale and found that the 2 clinical groups produced higher ROD scores than the undergraduates. In addition, recent studies by Duberstein and Talbot (1993) and Fowler, Hilsenroth, and Handler (1996) provide evidence for an object relations model of dependency that suggests that a balance between anaclitic dependence and complete independence, in which dependency needs are acknowledged but are not overwhelming, is most adaptive. This model of dependency was evaluated; it was found that a simple difference in group means provided a better fit with the data, although some evidence of an object relations model also was found. Finally, Rorschach and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) levels of general defensiveness and primary process manifestations in Rorschach content were investigated to assess whether participants were responding defensively to the testing and whether there were any differences in the nature of oral-dependent responses between the clinical groups.     

Chimpanzee responding during matching to sample: control by exclusion

Three chimpanzees performed a computerized matching-to-sample task in which samples were photographs of items and comparison stimuli were geometric symbols called lexigrams. In Experiment 1, samples were either defined (i.e., they represented items that were associated already with a specific lexigram label by the chimpanzees) or undefined (i.e., they did not have an already learned association with a specific lexigram). On each trial, the foil (incorrect) comparison could be either a defined or an undefined lexigram. All 3 chimpanzees selected the correct comparison for undefined samples at a level significantly better than chance only when the foil comparison was defined. In Experiment 2, three comparisons were presented on each trial, and in Experiment 3, four comparisons were presented on each trial. For Experiments 2 and 3, the foil comparisons consisted of either defined or undefined comparisons or a mixture of both. For these two experiments, when the chimpanzees were presented with an undefined sample, they typically made selections of only undefined comparisons. These data indicate that the chimpanzees responded through use of exclusion. A final experiment, however, indicated that, despite the use of exclusion to complete trials with undefined samples correctly, the chimpanzees did not learn new associations between undefined samples and comparisons.     

Hearing speech against spatially separate competing speech versus competing noise

Listeners had the task of following a target speech signal heard against two competitors either located at the same spatial position as the target or displaced symmetrically to locations flanking it. When speech was the competitor, there was a significantly higher separation effect (maintained intelligibility with reduced target sound level), as compared with either steady-state or fluctuating noises. Increasing the extent of spatial separation slightly increased the effect, and a substantial contribution of interaural time differences was observed. When same- and opposite-sex voices were used, a hypothesis that the similarity between target and competing speech would explain the role for spatial separation was partly supported. High- and low-pass filtering showed that both parts of an acoustically similar competing signal contribute to the phenomenon. We conclude that, in parsing the auditory array, attention to spatial cues is heightened when the components of the array are confusable on other acoustic grounds.     

Free-swinging attention

Psychoanalytic listening enlists the analyst's capacity for, and relative comfort in, rapidly shifting levels of attention and organization. Such shifts are not effortless and can be characterized as part of "free-swinging attention," a term that suggests some dimensions of the analyst's work. The need to establish meaning in the individual and immediate context parallels the task of a child in learning language, and the role of the analyst as child is an important if usually overlooked one. The author compares psychoanalytic with psychotherapeutic listening, as well as some current views on free association and evenly suspended attention.     

Mechanisms of source confusion and discounting in short-term priming: 1. Effects of prime duration and prime recognition

Huber, Shriffrin, Lyle, and Ruys (2001) measured short-term repetition priming effects in perceptual identification with two-alternative forced-choice testing. There was a preference to choose repeated words following passive viewing of primes and a preference against choosing repeated words following active responding to primes. In this present study, we explored conditions of prime processing that produce this pattern of results. Experiment 1 revealed that increased prime duration under passive viewing instructions produces the active priming pattern. Experiment 2 assessed memory for primes: With poor recognition of primes, there was a strong preference for repeated words; however, with good recognition of primes, this preference was eliminated. These results are modeled by a computational theory of optimal decision making, responding optimally with unknown sources of evidence (ROUSE). In ROUSE, a preference for repeated words results from source confusion between primes and choice words. A reversal in the direction of preference arises from the discounting of words known to have also appeared as primes.     

Background beliefs in Bayesian inference

We report five experiments in which the role of background beliefs in social judgments of posterior probability was investigated. From a Bayesian perspective, people should combine prior probabilities (or base rates) and diagnostic evidence with equal weighting, although previous research shows that base rates are often underweighted. These experiments were designed so that either piece of information was supplied either by personal beliefs or by presented statistics, and regression analyses were performed on individual participants to assess the relative influence of information. We found that both prior probabilities and diagnostic information significantly influenced judgments, whether supplied by beliefs or by statistical information, but that belief-based information tended to dominate the judgments made.     

Sentence processing strategies in healthy seniors with poor comprehension: an fMRI study

We used fMRI to examine patterns of brain recruitment in 22 healthy seniors, half of whom had selective comprehension difficulty for grammatically complex sentences. We found significantly reduced recruitment of left posterolateral temporal [Brodmann area (BA) 22/21] and left inferior frontal (BA 44/6) cortex in poor comprehenders compared to the healthy seniors with good sentence comprehension, cortical regions previously associated with language comprehension and verbal working memory, respectively. The poor comprehenders demonstrated increased activation of left prefrontal (BA 9/46), right dorsal inferior frontal (BA 44/6), and left posterior cingulate (BA 31/23) cortices for the grammatically simpler sentences that they understood. We hypothesize that these brain regions support an alternate, nongrammatical strategy for processing complex configurations of symbolic information. Moreover, these observations emphasize the crucial role of the left perisylvian network for grammatically guided sentence processing in subjects with good comprehension.