A model of probabilistic category learning.

A new connectionist model (named RASHNL) accounts for many irrational phenomena found in nonmetric multiple-cue probability learning, wherein people learn to utilize a number of discrete-valued cues that are partially valid indicators of categorical outcomes. Phenomena accounted for include cue competition, effects of cue salience, utilization of configural information, decreased learning when information is introduced after a delay, and effects of base rates. Exps 1 and 2 replicate previous experiments on cue competition and cue salience, and fits of the model provide parameter values for making qualitatively correct predictions for many other situations. The model also makes 2 new predictions, confirmed in Exps 3 and 4. The model formalizes 3 explanatory principles: rapidly shifting attention with learned shifts, decreasing learning rates, and graded similarity in exemplar representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Covariation in natural causal induction.

The covariation component of everyday causal inference has been depicted, in both cognitive and social psychology as well as in philosophy, as heterogeneous and prone to biases. The models and biases discussed in these domains are analyzed with respect to focal sets: contextually determined sets of events over which covariation is computed. Moreover, these models are compared to the authors' probabilistic contrast model, which specifies causes as first and higher order contrasts computed over events in a focal set. Contrary to the previous depiction of covariation computation, the present assessment indicates that a single normative mechanism, the computation of probabilistic contrasts, underlies this essential component of natural causal induction both in everyday and in scientific situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms of predictive and diagnostic causal induction.

In predictive causal inference, people reason from causes to effects, whereas in diagnostic inference, they reason from effects to causes. Independently of the causal structure of the events, the temporal structure of the information provided to a reasoner may vary (e.g., multiple events followed by a single event vs. a single event followed by multiple events). The authors report 5 experiments in which causal structure and temporal information were varied independently. Inferences were influenced by temporal structure but not by causal structure. The results are relevant to the evaluation of 2 current accounts of causal induction, the Rescorla-Wagner (R. A. Rescorla & A. R. Wagner, 1972) and causal model theories (M. R. Waldmann & K. J. Holyoak, 1992). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are causal attributions causal? A path analysis of the cognitive model of achievement motivation.

Tested the causal assumptions of B. Weiner's (1972, 1974, 1977) cognitive reinterpretation of the traditional theory of achievement motivation. Ss were 206 college students varying in resultant achievement motivation who experienced feelings of failure in a course test and chose to take the exam a second time under a mastery learning system. After feedback on first test performance, Ss made attributions for their initial failure, indicated degree of shame, and rated their expectancy for success on the second test opportunity. Treatment of this system of nonmanipulated variables by path analysis techniques provided little support for the contention that variations in expectancy and retest performance depend on attributions made for a previous failure. Affect depends in part on internal attributions, but in a direction opposite to predictions. An alternative interpretation of the role of cognitive attributions in the achievement process is explored. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic updating in DIAS-NIDDM and DIAS causal probabilistic networks

In order to evaluate in humans the safety and immunogenicity of a Pseudomonas aeruginosa vaccine composed of outer membrane proteins (OMPs), CFC-101, we carried out a phase I/IIa clinical trial in healthy male volunteers. Groups of six volunteers were immunized either subcutaneously (s.c.) or intramuscularly (i.m.) with three dosages of the vaccine three times at 7-day intervals. The vaccine was well tolerated by volunteers. Local reactions in the injection sites were generally mild and transient. Significant increases in OMP-specific antibody were observed in both route groups after vaccinations but was higher in the i.m.-immunized group, where vaccination with 0.5 or 1.0 mg doses yielded 100% seroconversion. The specificity of the induced antibodies to P. aeruginosa OMP was demonstrated by western blot analysis and immunoprecipitation assay. An increase in Clq-binding capacity and ability to confer mice protection from lethal challenges with P. aeruginosa indicated the protective efficacy of the elicited antibodies. Based on these data, we concluded that the P. aeruginosa OMP vaccine is safe and effective in humans with an optimal dose of 0.5 and 1.0 mg and that i.m. is the better route than s.c. for this vaccine.     

Attributional information processing: A response time model of causal subtraction.

Response time measures have been used occasionally in social psychology, but rarely as direct probes of information processing. A study (with 24 undergraduates) collecting response time data in a near-exact replication of L. McArthur's (see record 1972-27156-001) classic attribution study sheds light on the information processing involved in Ss' responses. The process is analyzed into 2 stages: (a) encoding or comprehension of the stimulus sentence and the consensus, distinctiveness, and consistency information and (b) attributional processing per se. In the 2nd stage, response time analyses suggest that perceivers operate by subtracting causes from an initial set to arrive at a response, rather than by adding causal components (person, stimulus, and circumstances) until an adequate cause is obtained. Subtraction is theoretically related to the salience model of attribution. Response time measures promise to expand greatly the ability of social psychologists to build process models of causal attribution and other kinds of social perception and cognition. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Making trade-offs: A probabilistic and context-sensitive model of choice behavior.

The stochastic difference model assumes that decision makers trade normalized attribute value differences when making choices. The model is stochastic, with choice probabilities depending on the normalized difference variable, d, and a decision threshold, delta. The decision threshold indexes a person's sensitivity to attribute value differences and is a free estimated parameter of the model. Depending on the choice context, a person may be more or less sensitive to attribute value differences, and hence delta may be used to measure context effects. With proportional difference used as the normalization, the proportional difference model (PD) was tested with 9 data sets, including published data (e.g., J. L. Myers, M. M. Suydam, & B. Gambino, 1965; A. Tversky, 1969). The model accounted for individual and group data well and described violations of stochastic dominance, independence, and weak and strong stochastic transitivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of trial order on contingency judgments: A comparison of associative and probabilistic contrast accounts.

Four experiments examined trial sequencing effects in human contingency judgment. In Experiments 1–3, ratings of contingency between a target cue and outcome were affected by the presentation order of a series of trials distributed in 2 distinct blocks and showed a recency bias. Experiment 4 replicated this effect when the trials were partly intermixed. These recency effects are predicted by an associative learning model that computes associative strengths trial by trial and incorporates configural coding of cues but are problematic for probabilistic contrast accounts, which currently have no provision in the contingency computation for the differential weighting of trials as a function of their order of presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A causal model approach to the symbolic interactionist view of the self-concept.

Examined the symbolic interactionist construct of the reflected self-concept using a causal model based on path analysis and multiple regression. 333 married couples, with husbands aged 20–88 yrs and wives aged 19–91 yrs were randomly selected and interviewed with a self-concept inventory. Measures of the reflected self were marriage partner's self-concept, partner's perception of spouse's evaluation (role taking), and spouse's actual evaluation. It is contended that this analysis was an advance beyond the traditional approach that simply tests for a relation between the self-concept and the actual and perceived evaluations of others. Use of a causal model accurately reflects the theoretical view of the self by emphasizing the process of role taking. Findings indicate that the actual evaluations by spouses did not have a direct effect on Ss' self-concepts but rather an indirect effect mediated via the Ss' perception of their spouses' evaluations of them. It is emphasized that an individual's perception of how he/she appears to others is the process whereby a self-concept becomes defined. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous assimilation of continuous values and temporal information in causal induction.

Existing models of causal induction primarily rely on the contingency between the presence and the absence of a causal candidate and an effect. Yet, classification of observations into these four types of covariation data may not be straightforward because (a) most causal candidates, in real life, are continuous with ambiguous, intermediate values and because (b) effects may unfold after some temporal lag, providing ambiguous contingency information. Although past studies suggested various reasons why ambiguous information may not be used during causal induction, the authors examined whether learners spontaneously use ambiguous information through a process called causal assimilation. In particular, the authors examined whether learners willingly place ambiguous observations into one of the categories relevant to the causal hypothesis, in accordance with their current causal beliefs. In Experiment 1, people's frequency estimates of contingency data reflected that information ambiguous along a continuous quantity dimension was spontaneously categorized and assimilated in a causal induction task. This assimilation process was moderated by the strength of the upheld causal hypothesis (Experiment 2), could alter the overall perception of a causal relationship (Experiment 3), and could occur over temporal sequences (Experiment 4). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A causal model of the career orientation and career choice of adolescent women.

Expanded on R. E. Fassinger's (see record 1990-21225-001) model of career choice in college women by testing 2 causal models of career choice and orientation with high school women. Ss were 409 adolescent women enrolled in their last year of high school in an all-female private liberal arts high school in a large Midwestern city. Structural equation modeling analyses suggested that the career orientation and career choice of adolescent women were predicted by ability, agentic characteristics, gender role attitudes, and relationship with mother. Young women who possessed liberal gender role attitudes, were instrumental and efficacious with regard to math and careers, and exhibited moderate degrees of attachment and independence from their mothers tended to value their career pursuits. Adolescent women who selected nontraditional and prestigious careers showed high ability and strong agentic characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An attentional model of dimensional contrast.

In this article, the authors introduce a model of dimensional stimulus control designed to explain dimensional contrast effects. The model suggests that dimensional contrast is the result of the nonuniform allocation of limited attentional resources during discrimination training. Attention in the model is conceived as a gradient that extends throughout a spatial representation of stimuli. The authors examine the results of 5 experiments to assess the quality of fit of the model and its theoretical implications. Variations in training procedures, such as changing presentation probability of stimuli, changing the distribution of training stimuli, and changing the relative difficulty of discrimination, can all be accounted for by differences in the allocation of attentional resources. The good fit of the model indicates that attentional limitations may play an important role in stimulus control phenomena such as dimensional contrast. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A longitudinal causal model of cardiac invalidism following myocardial infarction

OBJECTIVE: To measure the distribution of the seriousness of illnesses and patients in primary care with the Duke Severity of Illness Scale (DUSOI) and relate it to resource use. DESIGN: Observational prospective study. SETTING: Eight primary care centres from the centre sub-section of the Catalan Health Service. PATIENTS AND OTHER PARTICIPANTS: For the first two months of the study, patients who attended for consultation at 9 general/family doctors' clinics were systematically sampled. 1,868 patients were selected and observed for 6 months. MEASUREMENTS AND MAIN RESULTS: The DUSOI was used to work out the seriousness of the illness and of the patient. The variables used as indicators of the use of resources for an illness were: the number of attendances, the time and costs of care. The same for the patient were: the number of attendances, number of episodes and costs of care. The average score for the seriousness of the episode was 31.4 with a standard deviation (SD) of 16.4. The correlations between use of resources and seriousness were under 0.4. The seriousness of the patient had an average of 44.9 (SD 21.3) and statistically significant correlations above 0.6 with the use of resources. CONCLUSIONS: The seriousness of the illnesses attended in primary care is low and is related moderately to the use of resources. DUSOI could be better employed in research, inasmuch as there are systems for classifying patients which have greater explanatory power and can be constructed from pre-existing data.     

A tetrad test for causal indicators.

The authors propose a confirmatory tetrad analysis test to distinguish causal from effect indicators in structural equation models. The test uses nested vanishing tetrads that are often implied when comparing causal and effect indicator models. The authors present typical models that researchers can use to determine the vanishing tetrads for 4 or more variables. They also provide the vanishing tetrads for mixtures of causal and effect indicators, for models with fewer than 4 indicators per latent variable, or for cases with correlated errors. The authors illustrate the test results for several simulation and empirical examples and emphasize that their technique is a theory-testing rather than a model-generating approach. They also review limitations of the procedure including the indistinguishable tetrad equivalent models, the largely unknown finite sample behavior of the test statistic, and the inability of any procedure to fully validate a model specification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A probabilistic model for the failure frequency of underground gas pipelines

A model is constructed for the failure frequency of underground pipelines per kilometer year, as a function of pipe and environmental characteristics. The parameters in the model were quantified, with uncertainty, using historical data and structured expert judgment. Fifteen experts from institutes in The Netherlands, the United Kingdom, Italy, France, Germany, Belgium, Denmark, and Canada participated in the study.