Teenage pregnancy: family syndrome?

A short term, longitudinal study was conducted in order to explore selected psychosocial characteristics of fourteen teenagers aged sixteen years or younger who became mothers, the subsequent interaction of the mother-infant dyads, and the development and attachment of their infants at twelve months. The sample was matched for socioeconomic and marital status, intellectual ability and ethnicity with non-pregnant teenagers and pregnant women twenty years or older. The subjects were given a psychological and social history test battery. The groups did not differ significantly on the personality tests. The pregnant women reported a significantly poorer daughter-father relationship than the nonpregnant controls. In a high proportion of cases it was found that their fathers were absent or ineffectual and the homes mother-ridden. The interview data suggest that a large number of the pregnancies were psychologically motivated.     

The effects of satiation and reinforcer develuation on signal-centered behavior in the rat

Two experiments are described which investigate the effects of satiation and reinforcer devaluation on signal-centered behavior in rats. In Experiment 1 lever contacts were established in hungry rats by pairing retractable lever presentations (CS) with response-independent food (UCS). Subsequently, food satiating these subjects significantly reduced the level of CS contact during an extinction test and, in particular, suppressed CS-directed licking and pawing. In Experiment 2 lever contacts which were established by lever-food pairings were suppressed when the food reinforcer was paired with lithium chloride (LiCl) induced illness. In particular, CS-directed licking, sniffing, and orienting were significantly suppressed by these food-LiCl pairings. These results suggest that signal-centered behavior (i) is not simply a manifestation of “conditioned hunger,” (ii) is determined to some extent by the animal's current need state, and (iii) is influenced by the status of specific reinforcer representations.     

The influence of sentential position on noun phrase structure priming

This article explores the interaction between global sentence context and local syntactic decision making. Specifically, four noun phrase (NP) structural priming experiments investigated whether the position of an NP within a sentence increased speakers' tendency to repeat primed structure. We crossed the position of the NP with the structure of the NP, such that NPs could be sentence initial or final in prime sentences. We further manipulated whether the to-be-modified target NP was sentence initial or final. Structural persistence effects were consistently observed, but there was no influence of parallel position. Rather, sentence-initial NP primes had a stronger influence on subsequent syntactic decisions than sentence-final primes, suggesting a primacy effect. Sentence-initial target NPs contributed to this primacy effect, while sentence-final target NPs did not. We argue that this primacy effect arises as the result of greater processing demands and resources for early than for late sentence constituents as well as deeper encoding and more focused attention when processing the beginnings of sentences.     

Detecting latent taxa: Monte Carlo comparison of taxometric, mixture model, and clustering procedures

A Monte Carlo evaluation of four procedures for detecting taxonicity was conducted using artificial data sets that were either taxonic or nontaxonic. The data sets were analyzed using two of Meehl's taxometric procedures, MAXCOV and MAMBAC, Ward's method for cluster analysis in concert with the cubic clustering criterion and a latent variable mixture modeling technique. Performance of the taxometric procedures and latent variable mixture modeling were clearly superior to that of cluster analysis in detecting taxonicity. Applied researchers are urged to select from the better procedures and to perform consistency tests.     

Social Support Mediates the Effects of Dual-Focus Mutual Aid Groups on Abstinence from Substance Use

Background: Specialized 12-step based groups have emerged to address the needs of persons recovering from both substance abuse and psychiatric illness. Objective: This study investigates the role of social support in mediating the association between mutual aid participation and subsequent substance use for dually diagnosed persons. Method: A cohort of Double Trouble in Recovery (DTR) members in New York City were studied prospectively over a two-year period. Findings: Longer DTR participation during the first year of the study was associated with lower substance use in the second year; that effect was partially explained by the maintenance of high level of social support. Conclusion: These findings speak of the enduring influence of 12-step attendance on reducing substance use, and underline the importance of both 12-step attendance and supportive networks for dually diagnosed persons.     

Syntactic priming in written production: Evidence for rapid decay

There is strong evidence for syntactic priming in language production (Bock, 1986), but little evidence about the time course of such effects. We report an experiment that examined the circumstances under which syntactic priming decays in written language production. Participants completed sentence fragments that allowed completions with one of two syntactic forms (Pickering & Branigan, 1998). They tended to produce the same syntactic form for immediately consecutive fragments, even though the two fragments described different events. However, when the experimental fragments were separated by other fragments with unrelated syntactic forms, this tendency rapidly diminished. The results suggest that priming effects in written production decay rapidly when other structures are subsequently produced. We discuss the implications for the application of syntactic information during production.     

Taxometric analysis of fuzzy categories: a Monte Carlo study

A small Monte Carlo study examined the performance of a form of taxometric analysis (the MAXCOV procedure) with fuzzy data sets. These combine taxonic (categorical) and nontaxonic (continuous) features, containing a subset of casts with intermediate degrees of category membership. Fuzzy data sets tended to yield taxonic findings on plot inspection and two popular consistency tests, even when the degree of fuzziness, i.e., the proportion of intermediate cases, was large. These results suggest that fuzzy categories represent a source of pseudotaxonic inferences, if on is understood in the usual binary, "either-or" fashion. This in turn implies that dichotomous causes cannot be confidently inferred when taxometric analyses yield apparently taxonic findings.