Human cognition and a pile of sand: a discussion on serial correlations and self-organized criticality

Recently, G. C. Van Orden, J. G. Holden, and M. T. Turvey (2003) proposed to abandon the conventional framework of cognitive psychology in favor of the framework of nonlinear dynamical systems theory. Van Orden et al. presented evidence that "purposive behavior originates in self-organized criticality" (p. 333). Here, the authors show that Van Orden et al.'s analyses do not test their hypotheses. Further, the authors argue that a confirmation of Van Orden et al.'s hypotheses would not have constituted firm evidence in support of their framework. Finally, the absence of a specific model for how self-organized criticality produces the observed behavior makes it very difficult to derive testable predictions. The authors conclude that the proposed paradigm shift is presently unwarranted.     

Evaluating the efficiency and community safety goals of the Broward County Mental Health Court

Mental health courts have developed as one response to persons with mental illness who are involved with the criminal justice system. This study investigated the efficiency and safety goals of one such court in Broward County, FL. Mental health court (MHC) clients spent significantly fewer days in jail for the index arrest associated with study enrollment than a comparison group. MHC clients had similar survival time to re-arrest up to one year after study enrollment. MHC clients did not significantly differ from the comparison group in self-reported aggressive acts over an 8 month follow-up period, while they did self-report significantly fewer acts of violence than the comparison group at the 8 month follow-up. These findings suggest that some of the benefits associated with the MHC reported in prior studies were not achieved at the expense of efficiency and safety.     

A neural network model of foraging decisions made under predation risk

This article develops the cognitive—emotional forager (CEF) model, a novel application of a neural network to dynamical processes in foraging behavior. The CEF is based on a neural network known as the gated dipole, introduced by Grossberg, which is capable of representing short-term affective reactions in a manner similar to Solomon and Corbit’s (1974) opponent process theory. The model incorporates a trade-off between approach toward food and avoidance of predation under varying levels of motivation induced by hunger. The results of simulations in a simple patch selection paradigm, using a lifetime fitness criterion for comparison, indicate that the CEF model is capable of nearly optimal foraging and outperforms a run-of-luck rule-of-thumb model. Models such as the one presented here can illuminate the underlying cognitive and motivational components of animal decision making.     

Shape-from-shading depends on visual, gravitational, and body-orientation cues

The perception of shading-defined form results from an interaction between shading cues and the frames of reference within which those cues are interpreted. In the absence of a clear source of illumination, the definition of 'up' becomes critical to deducing the perceived shape from a particular pattern of shading. In our experiments, twelve subjects adjusted the orientation of a planar disc painted with a linear luminance gradient from one side to the other, until the disc appeared maximally convex-that is, until the luminance gradient induced the maximum perception of a three-dimensional shape. The vision, gravity, and body-orientation cues were altered relative to each other. Visual cues were manipulated by the York Tilted Room facility, and body cues were altered by simply lying on one side. The orientation of the disc that appeared maximally convex varied in a systematic fashion with these manipulations. We present a model in which the direction of perceptual 'up' is determined from the sum of three weighted vectors corresponding to the vision, gravity, and body-orientation cues. The model predicts the perceived direction of 'up', contributes to our understanding of how shape-from-shading is deduced, and also predicts the confidence with which the 'up' direction is perceived.     

Index of suspicion: feeling not believing

Throughout the U.S., state laws require professionals who work with children to report cases of suspected child abuse to child protection services. Both practically and conceptually, however, significant problems arise from a lack of clarity regarding the threshold that has been set for reporting. Specifically, there is no consensus as to what constitutes reasonable suspicion, and little direction for how mandated reporters should gauge their legal and professional responsibilities when they harbor suspicion. In this paper we outline the context of the problem, discuss the nature and scope of its conceptual underpinnings, and offer recommendations for moving towards a concrete, practical solution.     

The Parents Matter! Program Interventions: Content and the Facilitation Process

The Parents Matter! Program (PMP) has developed three interventions for parents of 4th and 5th grade African-American children (9–12 years old). The overarching goal of all three interventions is to provide parents with knowledge, skills, and support for enhancing their efforts to raise healthy children. The interventions are: (1) Enhanced Communication and Parenting (five 2 -hour sessions), (2) Brief Communication and Parenting (single 2 -hour session), and (3) General Health (single 2 -hour session). This article discusses the development of these interventions, presents an overview of the content of each intervention, and discusses issues related to the facilitation/presentation of these interventions.     

Senior capstone design and ethics: A bridge to the professional world

A senior level capstone design experience has been developed and offered with a particular emphasis on many of the professional issues raised in Accreditation Board for Engineering and Technology (ABET) Engineering Criterion IV. The course has sought to develop student awareness of the ethical foundation of the engineering profession, the global and societal framework within which engineers practice, and the environmental impact on engineering. The capstone design course also focused upon improving the technical communications skills of the graduating senior class with both extensive instruction in writing and multiple workshops dealing with the art of making an effective oral presentation. The effectiveness of the design course was assessed using Kirkpatrick’s model for evaluating training programs. An earlier version of this paper was presented at the “Ethics and Social Responsibility in Engineering and Technology” meeting, New Orleans, 2003.     

A diffusion model analysis of the effects of aging in the lexical-decision task

The effects of aging on response time (RT) are examined in 2 lexical-decision experiments with young and older subjects (age 60-75). The results show that the older subjects were slower than the young subjects, but more accurate. R. Ratcliff s (1978) diffusion model provided a good account of RTs, their distributions, and response accuracy. The fits show an 80-100-ms slowing of the nondecision components of RT for older subjects relative to young subjects and more conservative decision criterion settings for older subjects than for young subjects. The rates of accumulation of evidence were not significantly different for older compared with young subjects (less than 2% and 5% higher for older subjects relative to young subjects in the 2 experiments).