On the Possibility of Skeptical Scenarios

Abstract: It is generally accepted that skeptical scenarios must be possible to raise legitimate skeptical doubt. I argue that if the possibility in question is supposed to be genuine metaphysical possibility, the skeptic's reasoning does not straightforwardly succeed. I first motivate the metaphysical possibility requirement on skeptical scenarios: it's a plausible position that several authors accept and that a family of prominent views—sensitivity, safety, relevant alternatives—are committed to. I argue that plausible constraints in modal epistemology show that justification for believing that certain global skeptical scenarios are metaphysically possible rests on some justified beliefs about the external world, and that this undermines the skeptical argument. While there may still be local skeptical challenges, skeptics cannot appeal to the metaphysical possibility of skeptical scenarios to generate global external world skepticism.     

A model of rotated mirror/normal letter discriminations

Rotated mirror/normal letter discriminations are thought to require mental rotation in order to determine the direction of facing of the stimulus. The response time (RT) function over orientation tends to be curved, rather than the linear function found for other mental rotation tasks. The present study investigated the possibility that the curved RT function is a result of a mixture of trials requiring and not requiring mental rotation. The results suggested that the frequency of mental rotation is also a linear function of stimulus orientation. Moreover, the relationship between an individual's rate of plane rotation and the mean difference in RT between mirror and normal stimuli was replicated, supporting the suggestion that mirrored stimuli are flipped after they are spun (Hamm, Johnson, & Corballis, 2004). On the basis of the present findings, the entire RT function can be modeled by using only the mean RTs for upright and inverted stimuli.     

Assessing the merits and faults of holistic and disaggregated judgments

Three studies explored both the advantages of and subjects' preferences for a disaggregated judgment procedure and a holistic one. The task in our first two studies consisted of evaluating colleges; the third study asked participants to evaluate job applicants. Holistic ratings consisted of providing an overall evaluation while considering all of the characteristics of the evaluation objects; disaggregated ratings consisted of evaluating each cue independently. Participants also made paired comparisons of the evaluation objects. We constructed preference orders for the disaggregated method by aggregating these ratings (unweighted or weighted characteristics). To compare the holistic, disaggregated, and weighted‐disaggregated method we regressed the four cues on the participant's holistic rating, on the linearly aggregated disaggregated ratings, and on the average weighted disaggregated rating, using the participant's “importance points” for each cue as weights. Both types of combined disaggregated ratings related more closely to the cues in terms of proportion of variance accounted for in Experiments 1 and 2. In addition, the disaggregated ratings were more closely related to the paired‐comparison orderings, but Experiment 2 showed that this was true for a small set (10) but not a large set (60) of evaluation objects. Experiment 3 tested the “gamesmanship” hypothesis: People prefer holistic ratings because it is easier to incorporate illegitimate but appealing criteria into one's judgment. The results suggested that the disaggregated procedure generally produced sharper distinctions between the most relevant and least relevant cues. Participants in all three of these studies preferred the holistic ratings despite their statistical inferiority. Copyright © 2009 John Wiley & Sons, Ltd.     

Development and evaluation of school-based violence prevention programs

Discusses key issues in developing and evaluating school-based violence prevention interventions. Schools provide a natural setting for implementing programs directed at teaching youth attitudes, knowledge, and skills to reduce their involvement in violence. Although multitudes of these programs exist, few have been rigorously evaluated. Developers of violence prevention programs need to pay particular attention to the type of violence being addressed, the target population, relevant risk and protective factors, and the target of the intervention. Conducting sound evaluations of such programs requires careful attention to the unit of randomization, treatment conditions, outcome measures, timing of data collection, and potential moderator variables. Efforts to develop effective prevention programs can be greatly facilitated by adopting an action-research strategy in which evaluation findings provide a basis for continual program refinement.     

The structure of self-reported aggression, drug use, and delinquent behaviors during early adolescence

Examined the structure of self-report scales designed to assess the frequency of adolescent problem behaviors. Urban (n = 988) and rural (n = 1,895) middle school students completed the Problem Behavior Frequency Scale (Farrell, Danish, & Howard, 1992a) and measures of other relevant constructs. Confirmatory factor analyses supported a model that included specific factors related to aggression, drug use, and delinquent behaviors, and a higher order problem behavior factor. Findings did not support a distinction between physical and nonphysical aggression. Results were generally consistent across settings (i.e., urban vs. rural) and gender. Other relevant constructs, including peer pressure for drug use and attitudes favoring aggression, had both specific associations with relevant first-order factors and more general associations with the second-order factor. These findings support the construction of separate scales assessing specific domains of problem behaviors in studies of adolescents' problem behaviors.     

How Perceptions Impact Recovery from Concussion in Childhood and Adolescence: a Systematic Review

Neuropsychology Review - Perceptions about the causes and consequences of concussion, and individual representations and interpretations of these factors, can influence the post-concussive recovery...     

A Psychometric Investigation of the Suicide Status Form II with a Psychiatric Inpatient Sample

We investigated the psychometric validity and reliability of the Suicide Status Form‐II (SSF‐II) developed by Jobes, Jacoby, Cimbolic, and Hustead (1997) . Participants were 149 psychiatric inpatients (108 suicidal; 41 nonsuicidal) at the Mayo Clinic. Each participant completed assessment measures within 24 hours of admission and 48–72 hours later. Factor analyses of the SSF core assessment produced a robust two‐factor solution reflecting chronic and acute response styles. The SSF core assessment had good to excellent convergent and criterion validity; pre‐post SSF ratings also demonstrated moderate test‐retest reliability. The results replicated previous research and show that the SSF‐II is psychometrically sound with a high‐risk suicidal inpatient sample.     

Psychosocial mediators of antiretroviral nonadherence in HIV-positive adults with substance use and mental health problems.

This study used data from 1,889 HIV-positive patients on antiretroviral (ARV) medications who participated in the HIV Cost and Services Utilization Study to investigate whether nonadherence to ARV medications among patients with mental health and substance use problems could be explained by difficulty getting and negative attitudes toward ARV medications, poor fit of the regimen with lifestyle, lack of instruction and cues for remembering the regimen from a health care provider, and poor support from others for taking ARV medications. Difficulty getting ARV medications and poor fit with lifestyle were significant mediators of nonadherence for patients with a probable psychiatric disorder. Difficulty getting medication was a mediator for heavy drinkers, and poor fit with lifestyle was a mediator for drug users who drank heavily. Further research is needed to identify and address the barriers to adherence in these populations.     

The wisdom of the crowd in combinatorial problems

The "wisdom of the crowd" phenomenon refers to the finding that the aggregate of a set of proposed solutions from a group of individuals performs better than the majority of individual solutions. Most often, wisdom of the crowd effects have been investigated for problems that require single numerical estimates. We investigate whether the effect can also be observed for problems where the answer requires the coordination of multiple pieces of information. We focus on combinatorial problems such as the planar Euclidean traveling salesperson problem, minimum spanning tree problem, and a spanning tree memory task. We develop aggregation methods that combine common solution fragments into a global solution and demonstrate that these aggregate solutions outperform the majority of individual solutions. These case studies suggest that the wisdom of the crowd phenomenon might be broadly applicable to problem-solving and decision-making situations that go beyond the estimation of single numbers.