An integrated theory of the mind

Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in ACT-R. These modules are associated with distinct cortical regions. These modules place chunks in buffers where they can be detected by a production system that responds to patterns of information in the buffers. At any point in time, a single production rule is selected to respond to the current pattern. Subsymbolic processes serve to guide the selection of rules to fire as well as the internal operations of some modules. Much of learning involves tuning of these subsymbolic processes. A number of simple and complex empirical examples are described to illustrate how these modules function singly and in concert.     

Reduction of left visual field lexical decision accuracy as a result of concurrent nonverbal auditory stimulation

To investigate whether concurrent nonverbal sound sequences would affect visual-hemifield lexical processing, lexical-decision performance of 24 strongly right-handed students (12 men, 12 women) was measured in three conditions: baseline, concurrent neutral sound sequence, and concurrent emotional sound sequence. With the neutral sequence, Naveteru, Roy, Ovelac, and Steinling (1992) had observed a right greater than left cerebral blood flow, and an opposite pattern with the emotional sequence. In the present study, the neutral sound sequence induced a significant accuracy reduction for lexical decisions to stimuli presented in the left visual field. It is hypothesized that RH activation in response to neutral sounds interferes with the limited lexical processing resources of that hemisphere.     

Perception of biological motion: A stimulus set of human point-light actions

We present a set of stimuli representing human actions under point-light conditions, as seen from different viewpoints. The set contains 22 fairly short, well-delineated, and visually “loopable” actions. For each action, we provide movie files from five different viewpoints as well as a text file with the three spatial coordinates of the point lights, allowing researchers to construct customized versions. The full set of stimuli may be downloaded fromwww.psychonomic.org/archive/.     

High school drinking and its consequences

The present study surveyed 930 high school students regarding self-reported alcohol use, their perceptions of parents and peers, and the negative consequences of drinking. Two-fifths of males and one-fifth of females reported frequent problem (binge) drinking. Problem drinkers reported more negative consequences associated with drinking. In addition, problem drinkers reported greater susceptibility to peer pressure, perceived their peers as drinking more, and reported less parental monitoring and more use of alcohol by parents. The results demonstrate the importance of both parent and peer variables in adolescent substance use and highlight the negative consequences of drinking reported by high school students.     

Client-level predictors of adherence to MST in community service settings

This study examined the association of youth and family characteristics with therapist fidelity to an evidence-based treatment provided in real world practice settings. Participants were 233 families that reported on the 66 therapists organized into 16 teams in nine organizations providing multisystemic therapy (MST). Therapist adherence ratings were lower for youths referred for both criminal offenses and substance abuse than for youths referred either for substance abuse or status offenses, and was negatively associated with pretreatment arrests and school suspensions. Adherence ratings were positively associated with educational disadvantage and caregiver-therapist ethnic match and marginally positively associated with economic disadvantage. The findings suggest directions for future research on the implementation of evidence-based treatments in community settings.     

Testing mediational models with longitudinal data: questions and tips in the use of structural equation modeling

R. M. Baron and D. A. Kenny (1986; see record 1987-13085-001) provided clarion conceptual and methodological guidelines for testing mediational models with cross-sectional data. Graduating from cross-sectional to longitudinal designs enables researchers to make more rigorous inferences about the causal relations implied by such models. In this transition, misconceptions and erroneous assumptions are the norm. First, we describe some of the questions that arise (and misconceptions that sometimes emerge) in longitudinal tests of mediational models. We also provide a collection of tips for structural equation modeling (SEM) of mediational processes. Finally, we suggest a series of 5 steps when using SEM to test mediational processes in longitudinal designs: testing the measurement model, testing for added components, testing for omitted paths, testing the stationarity assumption, and estimating the mediational effects.     

Four studies extending the utility of the Schwartz Outcome Scale (SOS-10)

The Schwartz Outcome Scale (SOS-10; Blais et al., 1999) is a brief, cost free, and easy to administer assessment device designed to measure a broad domain of psychological health. The 4 studies using the SOS-10 reported here extend the initial reliability and validity studies beyond psychiatric patients in a hospital setting to examine (a) test-retest reliability in a college student population, (b) concurrent validity with college students using an indirect technique assessing maladjustment, (c) concurrent validity with college counseling center clients using a self-report measure of client distress, and (d) sensitivity to treatment changes with outpatient clients. These studies lend further support for using the SOS-10 as a measure of psychological well-being and as an outcome measure in varied settings.     

Bias in exponential and power function fits due to noise: Comment on Myung,Kim, and Pitt

Myung, Kim, and Pitt (2000) demonstrated that simple power functions almost always provide a better fit to purely random data than do simple exponential functions. This result has important implications, because it suggests that high noise levels, which are common in psychological experiments, may cause a bias favoring power functions. We replicate their result and extend it by showing strong bias for more realistic sample sizes. We also show that biases occur for data that contain both random and systematic components, as may be expected in real data. We then demonstrate that these biases disappear for two- or three-parameter functions that include linear parameters (in at least one parameterization). Our results suggest that one should exercise caution when proposing simple power and exponential functions as models of learning. More generally, our results suggest that linear parameters should be estimated rather than fixed when one is comparing the fit of nonlinear models to noisy data.     

Parallel allocation of attention prior to the execution of saccade sequences

In a series of 5 experiments, the allocation of attention prior to the execution of saccade sequences was examined by using a dual-task paradigm. In the primary task, participants were required to execute a sequence of 2 endogenous saccades. The secondary task was a forced-choice letter identification task. During the programming of the saccade sequences, letters were briefly presented at the saccade goals and at no-saccade locations. The results showed that performance was better for letters presented at any of the saccade goals than for letters presented at any of the no-saccade locations. The results support a spatial model that assumes that prior to the execution of a saccade sequence, attention is allocated in parallel to all saccade goals. ((c) 2003 APA, all rights reserved)