Differential association of traits of fear and anxiety with norepinephrine- and dark-induced pupil reactivity.

The relation between fear and anxiety remains unclear, though psychometric data strongly suggest they are independent emotional systems. Because central norepinephrine (NE) projection systems are at the core of models of both fear and anxiety, the present experiment explored whether this independence extends to NE functioning. Two different aspects of NE functioning were assessed in a healthy young adult sample (N = 18): pupillary reactivity to (a) a specific NE alpha-1 agonist challenge to assess receptor reactivity and (b) a darkness challenge to assess contributions of central NE. Pupillary reactivity to the former was strongly and specifically related to A. Tellegen's (1982) Multidimensional Personality Questionnaire (MPQ) Harm Avoidance scale (i.e., trait fear), whereas the latter was strongly and specifically related to MPQ Negative Emotionality (i.e., trait anxiety). Implications for conceptualizing fear and anxiety as emotional systems are discussed.     

Developmental aspects of delinquency and internalizing problems and their association with persistent juvenile substance use between ages 7 and 18.

Analyzed longitudinal data from 3 samples of the Pittsburgh Youth Study on boys ages 7 to 18 to examine the co-occurrence of persistent substance use with other problem behaviors, including attention deficit hyperactivity disorder (ADHD), persistent delinquency, and persistent internalizing problems (i.e., depressed mood, anxiety, shy or withdrawn behavior). In preadolescence, persistent substance users also tended to be persistent delinquents, and half of this group displayed persistent internalizing problems as well. In adolescence, a third of the persistent substance users did not manifest other persistent problems. Across the samples, the least common substance users were those who manifested persistent internalizing problems only. Logistic regression analyses showed that persistent substance use in preadolescence was predicted by persistent delinquency and internalizing problems and in adolescence by persistent delinquency only. The combination of persistent substance use and delinquency was predicted by oppositional defiant disorder in middle childhood and by persistent internalizing problems in middle to late childhood. ADHD was not a predictor of persistent substance use (and delinquency) in any of the analyses. Results are discussed in terms of developmental models of multiproblem youth with an eye on improving early interventions.     

A “Primer” in Conceptual Metaphor for Counselors

Conceptual metaphor provides a potentially powerful counseling framework, generalizable across theoretical orientations. According to the conceptual perspective, metaphor is not merely a matter of language, but is an indispensable dimension of human understanding and experience whereby more abstract ideas (like relationships) are understood in terms of more concrete experiences (like journeys). Consequently, when a couple in counseling says, “we're just spinning our wheels,” they are not only using a common colloquial expression, but also giving information about how they conceptualize their relationship. This article provides a theoretical foundation for use of conceptual metaphor and offers examples of its potential for counseling.     

Psychophysics of remembering

We present a new model of remembering in the context of conditional discrimination. For procedures such as delayed matching to sample, the effect of the sample stimuli at the time of remembering is represented by a pair of Thurstonian (normal) distributions of effective stimulus values. The critical assumption of the model is that, based on prior experience, each effective stimulus value is associated with a ratio of reinforcers obtained for previous correct choices of the comparison stimuli. That ratio determines the choice that is made on the basis of the matching law. The standard deviations of the distributions are assumed to increase with increasing retention-interval duration, and the distance between their means is assumed to be a function of other factors that influence overall difficulty of the discrimination. It is a behavioral model in that choice is determined by its reinforcement history. The model predicts that the biasing effects of the reinforcer differential increase with decreasing discriminability and with increasing retention-interval duration. Data from several conditions using a delayed matching-to-sample procedure with pigeons support the predictions.     

Acute Ethanol Administration Impairs Spatial Performance While Facilitating Nonspatial Performance in Rats

Acute ethanol administration produces learning and memory impairments similar to those found following lesions to the hippocampal system in rats. For example, both ethanol and hippocampal lesions impair performance on spatial learning and memory tasks while sparing performance on many nonspatial learning and memory tasks. Lesions to the hippocampal system can also alter the nature of the information that the animal uses to guide its behavior, from using spatial information to using individual cues. In the present experiment, rats were trained, while sober, to navigate on an eight-arm radial arm maze to a specific arm for food reward. During training, the rewarded arm was always in the same specific location and contained well-defined cues. After the rat learned the task, a memory test was conducted under different doses of ethanol (0.0 g/kg [saline control], 1.0, 1.5, or 2.0 g/kg, intraperitoneal). On the test day the maze was rotated so that the cued arm was 90 degrees to the right of its original position. During testing, intact rats showed a significant bias to approach the place where they had been previously rewarded, even though the cue was no longer located there. Acute ethanol administration dose dependently reduced approaches to the rewarded place. However, ethanol administration did not result in increases in random choices; rather, it resulted in a dose-dependent increase in approaches to the cued arm, now in a new location. These results extend previous research showing that acute ethanol administration and lesions to the hippocampal system produce similar effects on learning and memory in rats.     

The behavioral theory of timing: Reinforcer rate determines pacemaker rate

In the behavioral theory of timing, pulses from a hypothetical Poisson pacemaker produce transitions between states that are correlated with adjunctive behavior. The adjunctive behavior serves as a discriminative stimulus for temporal discriminations. The present experiments tested the assumption that the average interpulse time of the pacemaker is proportional to interreinforcer interval. Responses on a left key were reinforced at variable intervals for the first 25 s since the beginning of a 50-s trial, and right-key responses were reinforced at variable intervals during the second 25 s. Psychometric functions relating proportion of right-key responses to time since trial onset, in 5-s intervals across the 50-s trial, were sigmoidal in form. Average interpulse times derived by fitting quantitative predictions from the behavioral theory of timing to obtained psychometric functions decreased when the interreinforcer interval was decreased and increased when the interreinforcer interval was increased, as predicted by the theory. In a second experiment, average interpulse times estimated from trials without reinforcement followed global changes in interreinforcer interval, as predicted by the theory. Changes in temporal discrimination as a function of interreinforcer interval were therefore not influenced by the discrimination of reinforcer occurrence. The present data support the assumption of the behavioral theory of timing that interpulse time is determined by interreinforcer interval.     

An investigation of the differential-outcomes effect within sessions

The differential-outcomes effect is manifest as more accurate performance of a delayed conditional discrimination when alternative choice responses are followed by different reinforcers than when they are followed by the same reinforcer. In Experiment 1, a differential-outcomes effect was demonstrated within sessions by signaling the duration of food access for correct responses with stimuli appearing in conjunction with the sample stimuli. The delayed matching-to-sample performance of 5 pigeons was more accurate when green choice responses (matching a green sample) were followed by 3.5-s food access and red choice responses (matching a red sample) were followed by 0.5-s food access (different-outcome trials) than when the correct choice responses were both followed by 1.5-s reinforcers (same-outcome trials). In Experiment 2, the acquisition of this differential-outcomes effect was characterized by a progressive decrease in rate of forgetting on different-outcome trials and no change in rate of forgetting on same-outcome trials. In addition, accuracy at the shortest delay intervals for both different-outcome and same-outcome trials increased over acquisition, but to a greater extent for different-outcome trials. These data suggest that both memorial and attentional (time-dependent and time-independent) factors contribute to the differential-outcomes effect.     

A Follow-up Dual-Task Investigation of Lateralized Effects in Right- and Left-Handed Males

A dual-task follow-up investigation examined the influence of sample size and ideational complexity of cognitive tasks on lateralized effects. With a larger sample (n = 128), results showed a "manual dominance effect" for relaxed and paced nonideational vocalized tasks. A hierarchy of ideational verbal tasks yielded the expected lateralized effects which corresponded with increasingly greater interference in concurrent tapping, but not in strength of lateralized effect. Instead of a trend seen in the earlier work (Steiner, Green, & White, 1992), results revealed a significant difference between handedness groups for one complex spatial task. Finally, outcomes for the other spatial task highlight the importance of assessing tradeoffs in attention.