Neurobiology of Cocaine-Induced Organic Brain Impairment: Contributions from Functional Neuroimaging

The present review is directed at imparting the current knowledge regarding functional neuroimaging as a tool for enhancing the understanding of cerebrophysiologic and neurobehavioral consequences of stimulant abuse. Stimulants like cocaine are capable of inducing clinically significant neurocognitive impairment through direct action on the brain, and indirectly through other organs that influence cerebral physiology. Neurochemical dysregulation including profound effects on the serotonergic and dopaminergic systems have substantial physiological and neurobehavioral consequences. Brain hemorrhages, transient ischemic attacks, strokes, and seizures frequently follow cocaine use. The residual cerebropathologic consequences of cocaine are seen only in significant or pronounced brain events when structural neuroimaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) are employed. However, recent research with newer functional neuroimaging techniques such as single photon emission, positron emission tomography, and quantitative electroencephalography have revealed high rates of significant alteration in brain function among cocaine users, with negative structural imaging studies. These findings are often associated with impairment on neuropsychological evaluation, also in the absence of positive findings on CT and MRI. Both cerebral metabolic and hypoperfusion anomalies are seen, especially in anterior and temporal brain regions. Observed changes can persist for months, and for some patients, may represent a permanent change in brain functioning.     

Implicit learning of complex structures: active adaptation and selective processing in acquisition and application

Subjects exposed to members of a structured domain become sensitive to the general structure of that domain, even when they are unaware that the domain has such structure (e.g., Reber, 1993). Numerous investigators have attempted to characterize this learning as unselective in acquisition and automatic in application. However, we contend that this characterization miscasts the fundamental nature of learning. In a series of experiments, we demonstrate that what subjects learn implicitly about the structure of a domain critically depends on decisions they make about how to organize the structural components. Similarly, the application of knowledge gained implicitly is not stable, but may be selected or even created under the demands of the test task. We conclude that implicit learning, just like explicit learning, proceeds through active organization of the stimulus complex, rather than by passively absorbing any level of structure. We propose a synthesis, in which learning, with and without awareness, is understood through a common set of principles.     

Caretaker Psychological Factors Predicting Premature Termination of Children's Counseling

This study examines the psychological factors associated with caretakers' premature termination of counseling for their children. Data were collected on the 85 primary caretakers of 85 children in Texas who applied for counseling at community mental health centers or who received private practitioner care. The general hypothesis of the study was that scores on general hostility, intrapunitive hostility, extrapunitive hostility, paranoid ideation, depression, and anxiety would discriminate caretakers who prematurely terminated their children's counseling from both those caretakers whose children, in the judgment of the counselors, met therapeutic goals and those caretakers whose children did not meet therapeutic goals but who attended at least 10 counseling sessions. The effect size results suggest that counselors should primarily consider caretaker intrapunitive hostility when anticipating potential premature termination of counseling for children.     

Does the Gun Pull the Trigger? Automatic Priming Effects of Weapon Pictures and Weapon Names

More than 30 years ago, Berkowitz and LePage (1967) published the first study demonstrating that the mere presence of a weapon increases aggressive behavior. These results have been replicated in several contexts by several research teams. The standard explanation of this weapons effect on aggressive behavior involves priming; identification of a weapon is believed to automatically increase the accessibility of aggression-related thoughts. Two experiments using a word pronunciation task tested this hypothesis. Both experiments consisted of multiple trials in which a prime stimulus (weapon or nonweapon) was followed by a target word (aggressive or nonaggressive) that was to be read as quickly as possible. The prime stimuli were words in Experiment 1 and pictures in Experiment 2. Both experiments showed that the mere identification of a weapon primes aggression-related thoughts. A process model linking weapons as primes to aggressive behavior is discussed briefly.     

A Critical Test of the Waist-to-Hip-Ratio Hypothesis of Female Physical Attractiveness

Recent research has led to increasingly sophisticated conjectures as to the roles that genetic heritage, prior experience, and environmental context play in the production and maintenance of complex behaviors. The field of evolutionary psychology was born of such conjectures (Stanley, 1895) and now serves as a niche for a growing number of researchers (Buss, 1995; Kenrick, 1994). One of the more provocative lines of experimental research to emerge from this alembic derives from the linkage of evolutionary theories of human mate selection with definitions of physical attractiveness based on somatic characteristics that simultaneously signal attractiveness and predict reproductive potential (Buss, 1989). The waist-to-hip ratio (WHR) has been purportedly demonstrated to be a robust example of just such an invariant perceptual cue (e.g., Henss, 1995; Singh, 1993a). Here, we report that judgments of attractiveness and fecundity can be either unrelated or related, positively or negatively, to the WHR depending on waist size, hip size, and weight, and are thus inconsistent with the evolutionary argument that human physical attractiveness is fundamentally a sign of mate value.     

The Evaluation of Parental Fitness in Termination of Parental Rights Cases: A Functional-Contextual Perspective

This article highlights issues involved in carrying out evaluations for termination of parental rights cases and suggests caution for mental health professionals doing such evaluations. It argues that current models of parenting that come from the child development and child maltreatment fields are too narrow in their focus to act as a foundation for such evaluations and are often based on research with select groups in our society making them open to bias. Similarly, it is argued that traditional assessment measures are limited in their utility for responding to the kinds of relational and basic care questions asked in such evaluations. A functional-contextual model is offered as an alternative with examples of potentially useful measurement strategies. With such a frame as a starting point, the field might progress to providing more useful information to courts. Future research directions to improve this practice arena are discussed.     

The start-stop procedure: Estimation

In four experiments investigating human timing, subjects produced estimates of sample durations by bracketing their endpoints. On each trial, subjects reproduced a sample duration by pressing a button before the estimated sample duration elapsed (start time) and releasing it after the estimated duration elapsed (stop time). From these responses, middle time (start + stop/2) and spread time (stop — start) were calculated, representing the point of subjective equality and the difference limen, respectively. In all experiments, subjects produced middle times that varied directly with sample duration. In Experiment 2, middle times lengthened when feedback was withheld. Consistent with Weber timing, spread times, as well as the standard deviation of middle times, varied directly with middle time (Experiments 1, 3, and 4). On the basis of an internal clock model of timing (Gibbon & Church, 1990), the data permitted inferences regarding memory processes and response threshold. Correlations between start and stop times and between start and spread times agreed with earlier findings in animals suggesting that the variance of temporal estimates across trials is based in part upon the selection of a single temporal memory sample from a reference memory store and upon one or two threshold samples for initiating and terminating each estimate within a trial.     

Conflict-Resolution Training and Middle School Students' Integrative Negotiation Behavior

This study examined the impact of conflict-resolution training on students' use of distributive and integrative negotiating procedures. In a midwestern, suburban middle school, 176 students (grades 6 through 9) participated in the study. Students were placed in a negotiation situation involving the buying and selling of commodities in which they could adopt a distributive (maximize own outcomes) or an integrative (maximize joint outcomes) negotiation approach. There were no significant differences between males and females or among students in the 6th, 7th, 8th, and 9th grades. The results of this study indicated that conflict-resolution and peer-mediation training resulted in the middle school students increasing their use of integrative negotiations and the positiveness of students' attitudes toward conflict.     

A fuzzy trace analysis of categorical inferences and instantial associations as a function of retention interval

Two experiments on children's inferences and associative memory provided a test of predictions from fuzzy-trace theory. Specifically, it was expected that gist-based false recognitions would increase with age and that false recognitions would be uncorrelated with verbatim memory. In Experiment 1, children in Grades 1 through 5 heard lists of category labels, clustered instances from categories, and individual instances. On an immediate test, children indicated whether or not they had previously heard a series of individually presented test words. This list consisted of old words, new words, or words that were categorically or semantically related to the studied word clusters. Children made more false recognition errors for instances than for categories. Verbatim memory and inferences were unrelated. In Experiment 2, the effect of a test delay on categorical inferences and associated instances was examined with children in Grades 1 to 6. With delay, false recognition of associated instances declined for children at all grade levels. In contrast, categorical inferences increased with delay for older children. Verbatim memory and inferences were uncorrelated under immediate and 1-day delay conditions, but there were some low but significant correlations across grades under the 7-day delay. The results of the two experiments are interpreted as supporting fuzzy-trace theory.     

Finding one's way home: Notes on the texture of moral experience

In this article, I seek to illuminate the texture of moral experience. I pursue that aim through a close reading of David Lean's film, Brief Encounter, produced in 1946. The chief protagonist in the film undergoes a moral odyssey that reveals and tests all that she has understood about how to conduct a life. Her experience sheds light on the constituents of an individual moral sensibility as well as how its enactment appears in practice when one confronts a heartfelt difficulty. I argue that moral experience is best understood through the idiom of narrative and character, rather than through ethical language that places formal or universal principle at the center of the moral life. In the workshop of the moral self, as Lean's protagonist reveals, the task is not to fashion or take on universal principles but rather to cultivate virtuous relations with other people in the here-and-now.