No Evidence of Suicide Increase Following Terrorist Attacks in the United States: An Interrupted Time‐Series Analysis of September 11 and Oklahoma City

There is substantial evidence of detrimental psychological sequelae following disasters, including terrorist attacks. The effect of these events on extreme responses such as suicide, however, is unclear. We tested competing hypotheses about such effects by employing autoregressive integrated moving average techniques to model the impact of September 11 and the Oklahoma City bombing on monthly suicide counts at the local, state, and national level. Unlike prior studies that provided conflicting evidence, rigorous time series techniques revealed no support for an increase or decrease in suicides following these events. We conclude that while terrorist attacks produce subsequent psychological morbidity and may affect self and collective efficacy well beyond their immediate impact, these effects are not strong enough to influence levels of suicide mortality.     

Cognitive Tendencies in Analogical Forecasting1

This article attempts to identify some cognitive tendencies involved in analogical forecasting of the outcomes of medical treatment. Sixty-one medical doctors were involved in two experimental tasks concerned with prediction of the outcomes of a new medical treatment when the result with a first patient was known to be either negative or positive. The same subjects were also tested by the Short Optimism/Pessimism Questionnaire (SO/PQ) to explore relationships between life attitude and the cognitive tendencies observed in the experiment. The following findings were reported: (1) The first step of forecasting was recognized as a Data Evaluation Process (DEP), where the physician decides if the given data are sufficient to forecast the result of the same treatment with a new patient. (2) Two cognitive tendencies were identified: non-data-suggested tendency—drawing a conclusion opposite to the data given; and data-suggested tendency—drawing an optimistic conclusion when forecasting from “positive” data and a pessimistic conclusion when forecasting from “negative” data. The second tendency appeared to be dominant; however, the “positive” data created a stronger atmosphere to draw conclusions on a negative outcome. (3) It was stated that analogical forecasting involves two integrated processes, i.e., concluding and asserting. If the integration process is not complete, the subject is drawing analogical conclusions with a low confidence. (4) An optimistic life attitude appeared to be an important factor in determining analogical forecasting.     

The effects of objectives and constraints on motor control strategy in reciprocal aiming movements

The goal of this study was to examine how the kinematics of reciprocal aiming movements were affected by both the objective of the movement and the constraints operating on that movement. In Experiment 1, the objective of the movement was indirectly manipulated by capitalizing on the fact that subjects determine their own accuracy and speed limits, despite uniform task instructions to move as quickly and accurately as possible. A Fitts' type reciprocal aiming paradigm was employed, in which 69 subjects were asked to move a stylus repetitively between two spatially separated targets. Four target widths were orthogonally combined with four movement amplitudes, resulting in 16 conditions. Movements were made on an X-Y digitizing tablet. Based on the mean variable error produced on both targets, subjects were differentiated post hoc into three movement objective groups: speed, accuracy, and speed-plus-accuracy. Kinematic analyses revealed that the programming and execution of movements were systematically influenced by both the movement objective and the movement constraints. That is, movement time, peak velocity, dwell time, acceleration and deceleration time, normalized acceleration and normalized deceleration varied systematically as a function of both the speed-accuracy movement objective and the movement constraints of target size and movement distance. Moreover, the consequences of changing the constraints of the movement were affected by an interaction with the objective of the movement. In Experiment 2, the objective of the movement was directly manipulated by varying speed and/or accuracy instructions to subjects. The basic results of Experiment 1 were substantiated. Overall, the results were consistent with the view that motor control is dependent upon sensory consequences.     

Categorical and algebraic aspects of Martin-Löf Type Theory

In the paper there are introduced and discussed the concepts of an indexed category with quantifications and a higher level indexed category to present an algebraic characterization of some version of Martin-Löf Type Theory. This characterization is given by specifying an additional equational structure of those indexed categories which are models of Martin-Löf Type Theory. One can consider the presented characterization as an essentially algebraic theory of categorical models of Martin-Löf Type Theory. The paper contains a construction of an indexed category with quantifications from terms and types of the language of Martin-Löf Type Theory given in the manner of Troelstra [11]. The paper contains also an inductive definition of a valuation of these terms and types in an indexed category with quantifications.     

Effects of attentional focusing on pain perception

Two experiments were conducted to examine the hypothesized differential effectiveness of two attentional focusing strategies in pain perception. In the first experiment, subjects (72 male college students) rated their levels of pain after being exposed to either low- or high-intensity pressure stimulation for 75 s. Subjects were instructed to use either an external or internal focus of attention during the pain induction. Results revealed that external focusing was more effective for coping than internal focusing across both levels of stimulus intensity. The second experiment was a replication of the first, and featured bolstered internal focusing and stimulus intensity manipulations. Results showed that high-intensity stimulation produced higher pain ratings than did low-intensity stimulation for subjects in the internal focusing conditions, but not for those in the external focusing conditions. The findings support the power of distraction strategies for dealing with short-term pain with a rapid onset. Theoretical implications are discussed.The authors thank Darwyn E. Linder and Daniel M. Landers for their help in development of this research. The authors are also indebted to Sarah Colley, Jona Davis, Nanci Neuberger, and Rebecca Roberts for their assistance in data collection.     

Attention and the order of items in short-term visual memory

Summary Subjects first detected a target presented at the left of fixation, and then attempted to report, in order, the first four items (numerals or shapes) in a stream of items presented to the right of fixation. At comparably difficult presentation rates, 10/s for numerals and 5/s for shapes, reports showed a mixture of correctly ordered items with items reported in a direction opposite to their order of presentation. Reports fit a three-parameter attention-gating model (AGM), which assumes that (1) after target detection, an attention gate opens briefly to allow items to enter visual short-term memory (VSTM), and (2) report order is determined by the attention each item receives in VSTM. Items presented either early or late in the stream tend to receive less attention and are thus reported as later than more central items. The fit to the AGM for both numerals and unlabelled shapes provides evidence that reports reflect order in short-term visual (rather than verbal) memory.This research was supported by USAF grant no. 84-ML-044     

How normal and retarded individuals monitor and regulate speed and accuracy of responding in serial choice tasks

These experiments investigate whether or not differences in the way that retarded and nonretarded individuals monitor and regulate speed and accuracy of responding contribute to the slower and more variable performance of retarded subjects on choice reaction time (RT) tasks. Rabbitt (1979, 1981) suggested that efficient choice RT performance is mediated by subjects tracking increasingly faster RT bands on successive trials until, by making and recognizing errors, they discover those very fast RT levels that should be avoided and those safe bands, just above typical error levels, that should be tracked. Experiments 1A and 1B established that most retarded subjects detect their errors as efficiently as nonretarded controls, a finding that excludes the possibility that retarded subjects do not monitor accuracy efficiently but achieve comparable levels of accuracy by consistently responding within very slow RT bands that minimize likelihood of errors. Experiment 2 showed that while a qualitatively similar trial-by-trial tracking mechanism mediates the performance of both groups, retarded subjects are less efficient at constraining RTs within very fast, but safe, bands. Increasing error probabilities at longer RTs suggest that momentary fluctuations in stimulus discriminability and/or attention are factors affecting RT variability in retarded subjects. The RT patterns for various sequences of correct responses initiated and terminated by errors suggest that the effective past experience (EPEX) guiding trial-by-trial RT adjustments of retarded subjects is short and inadequate, and it was argued that this can account for much of the remaining RT variability contributing to retarded-nonretarded differences. Not only does a short EPEX increase variability by giving rise to long error-free sequences of slower than average RT but also, when combined with occasional specified random fluctuations, it suggests why retarded subjects can achieve, but not sustain, RT levels maintained by nonretarded subjects.     

The experience of self-awareness and its relation to level of self-consciousness: An experiential sampling study

The present research studied self-awareness by utilizing experiential sampling methodology, which allows for the random sampling of individuals' thoughts and feelings as they go about their normal daily activities. Neither Study 1 nor 2 found a relation between private or public self-awareness and negative affect. However, attention to private self-aspects was generally more positive and less ruminative for low as opposed to high private self-conscious subjects, and awareness of oneself as a social object was generally more positive but less important for low as opposed to high public self-conscious subjects. What may have accounted for the negative relation between private self-consciousness and average affect was that low private self-conscious subjects were more likely to attend to their private self-aspects if they were pleasant than if they were unpleasant, while high private self-conscious subjects' degree of private self-awareness was unrelated to whether the content of this state was pleasant or not. These findings are consistent with the hypothesis that low private self-conscious individuals engage in a more selective type of self-attention when in the private self-aware state than do high private self-conscious individuals. Regarding the relation between self-awareness and social context, both studies found that the presence of others results in a heightened public self-awareness. However, even though subjects were more attentive to public self-aspects when with others than when alone, in general, they were more attentive to their “private self” than to their “public self”. Results are discussed in terms of current self-awareness theory.