Psychological effects of attack on the World Trade Center: analysis before and after

Four different studies using a total sample of 711 from the same New York City student population tested a model that has emerged from previous research on disasters. The model suggests that postdisaster psychological distress is a function of exposure to the disaster, predisaster psychological distress, acute distress following the disaster, time elapsed between disaster and observation of distress, and additional traumatic experiences since the disaster. Although findings replicate those of previous cross-sectional studies regarding association of exposure and distress after the disaster, before and after studies did not detect an effect on postdisaster psychological distress of the World Trade Center attack. Great caution must be used in attributing elevated psychological distress observed postdisaster to the effects of the disaster.     

Explanations versus applications: the explanatory power of valuable beliefs

People hold beliefs that vary not only in their perceived truth, but also in their value to the believer--their meaning, relevance, and importance. We argue that a belief's value is determined, at least in part, by its explanatory power. Highly valuable beliefs are those that can uniquely explain and organize a diverse set of observations. Less valuable beliefs, in contrast, are those that can be explained by other observations, or that explain and organize few observations. The results of three experiments are consistent with these hypotheses. These experiments demonstrate that applying either scientific or religious beliefs to explain other observations increases the perceived value of those beliefs, whereas generating explanations for the existence of beliefs decreases their perceived value. Discussion focuses on the implications of these findings for people's resistance to explaining their own beliefs, for the perceived value of science and religion, and for culture wars between people holding opposing beliefs.     

Effects of adding a second reinforcement alternative: implications for Herrnstein's interpretation of r(e)

Herrnstein's hyperbola describes the relation between response rate and reinforcer rate on variable-interval (VI) schedules. According to Herrnstein's (1970) interpretation, the parameter r(e) represents the reinforcer rate extraneous to the alternative to which the equation is fitted (the target alternative). The hyperbola is based on an assumption that extraneous reinforcer rate remains constant with changes in reinforcer rate on the target alternative (the constant-r(e) assumption) and that matching with no bias and perfect sensitivity occurs between response and reinforcer ratios. In the present experiment, 12 rats pressed levers for food on a series of 10 VI schedules arranged on the target alternative. Across conditions, six VI values and extinction were arranged on a second alternative. Reinforcer rate on the second alternative, r2, negatively covaried with reinforcer rate on the target alternative for five of the six VI values on the second alternative, and significant degrees of bias and undermatching occurred in response ratios. Given covariation of reinforcer rate on the second and target alternatives, the constant-r(e) assumption can be maintained only by assuming that reinforcer rate from unmeasured background sources, rb, covaries with reinforcer rate on the second alternative such that their sum, r(e), remains constant. In a single-schedule arrangement, however, r(e) equals rb and thus rb is assumed to remain constant, forcing a conceptual inconsistency between single- and concurrent-schedule arrangements. Furthermore, although an alternative formulation of the hyperbola can account for variations in bias and sensitivity, the modified equation also is based on the constant-r(e) assumption and therefore suffers from the same logical problem as the hyperbola when reinforcer rate on the second alternative covaries with reinforcer rate on the target alternative.     

Improving construct validity: Cronbach, Meehl, and Neurath's ship

Smith's article "On Construct Validity: Issues of Method and Measurement" is a fine tribute to L. J. Cronbach and P. E. Meehl (1955) that clarifies the current state and future directions in the understanding of construct validity. Construct validity is a dynamic process, and fit indices need to be used at the service of understanding, not in place of it. The failure of a study or set of studies to support a construct, a measure, or the theory underlying it admits of many explanations, and the ways scientists interpret such failures are prone to cognitive biases and motivated reasoning. This suggests why metrics designed to index the extent to which observations match expectations can be useful prostheses to scientific judgments. As P. E. Meehl (1954) showed decades ago, quantitative, statistical formulas and indices tend to outperform informal, qualitative judgments, and this applies as much to the way researchers evaluate constructs and measures as to judgments in the consulting room.     

Thought suppression mediates the relationship between negative affect and borderline personality disorder symptoms

The purpose of this study was to examine the relationships among negative affect, childhood sexual abuse (CSA), thought suppression, and diagnostic symptoms of borderline personality disorder (BPD) in a community sample (n=127). Findings suggest that the temperamental variable negative affect intensity/reactivity was a stronger predictor of BPD symptoms than CSA. In addition, results indicated that higher thought suppression mediated the relationship between negative affective intensity/reactivity and BPD symptoms, after controlling for a history of CSA. Overall, findings suggest that (a) negative affectivity may be a better predictor of BPD symptoms than CSA, and (b) chronic efforts to suppress unpleasant thoughts may be a regulation strategy underlying the relationship between intense negative emotions and BPD symptoms.     

Psychological status and levels of sleepiness-alertness among patients with insomnia

Are symptoms of daytime sleepiness relevant among patients with insomnia? Patients with insomnia frequently report daytime consequences secondary to their difficulty initiating and maintaining sleep. The purpose of this study was to determine the frequency of daytime sleepiness as defined by a self-reported measure of daytime sleepiness (the Epworth Sleepiness Scale). In addition, the study characterized the patients' psychological status using the Symptom Checklist-90-Revised. The study corroborated a relatively high frequency of excessive daytime sleepiness and psychiatric conditions among patients with insomnia. Furthermore, the results of the study suggest variation in psychological distress levels, according to the different levels of sleepiness/alertness.     

A game-theoretic analysis of bargaining with reputations

In this paper we introduce and discuss some models of bargaining. These have the form of repeated plays of a game among pairs of individuals, with the opponents in each particular game drawn randomly from a large population. The players' information about one another is limited to a single quantity, termed reputation, which summarizes the behavior of a player in previous trials of the game, and so changes endogenously. We distinguish some possible decision rules or “customs” which players might use to determine their moves in the game as a function of their own and their opponent's reputation, and investigate whether or not these actions lead to a suitably defined social equilibrium. We then compare the equilibrium customs from the point of view of the welfare of the population as a whole.     

Handwriting as a correlate of extraversion

The validity of graphologists' claims that handwriting is a measure of extraversion was examined in this study. Three handwriting measures, line slope, letter slant, and letter width were chosen, and the relationship between these measures and extraversion as measured by the Eysenck Personality Inventory was studied. The subjects were 58 tertiary students. No significant correlations between the handwriting measures and extraversion were found, nor were there significant intercorrelations between the three handwriting measures. Thus the results did not support the claim that the three handwriting measures were valid indices of extraversion.