Sleep deprivation affects multiple distinct cognitive processes

Sleep deprivation adversely affects the ability to perform cognitive tasks, but theories range from predicting an overall decline in cognitive functioning (because of reduced stability in attentional networks) to claiming specific deficits in executive functions. In the present study, we measured the effects of sleep deprivation on a two-choice numerosity discrimination task. A diffusion model was used to decompose accuracy and response time distributions in order to produce estimates of distinct components of cognitive processing. The model assumes that, over time, noisy evidence from the task stimulus is accumulated to one of two decision criteria and that parameters governing this process can be extracted and interpreted in terms of distinct cognitive processes. The results showed that sleep deprivation affects multiple components of cognitive processing, ranging from stimulus processing to peripheral nondecision processes. Thus, sleep deprivation appears to have wide-ranging effects: Reduced attentional arousal and impaired central processing combine to produce an overall decline in cognitive functioning.     

A bumpy train ride: a field experiment on insult, honor, and emotional reactions

The present research examined the relationship between adherence to honor norms and emotional reactions after an insult. Participants were 42 Dutch male train travelers, half of whom were insulted by a confederate who bumped into the participant and made a degrading remark. Compared with insulted participants with a weak adherence to honor norms, insulted participants with a strong adherence to honor norms were (a) more angry, (b) less joyful, (c) less fearful, and (d) less resigned. Moreover, insulted participants with a strong adherence to honor norms perceived more anger in subsequent stimuli than not-insulted participants with a strong adherence to these norms. The present findings support a direct relationship among insult, adherence to honor norms, and emotional reactions.     

Civic community and violent behavior in Italy

The aim of this study was to examine to what extent community characteristics counterbalance propensities towards homicide and robbery. Data were obtained for each of the 95 Italian provinces on homicide rate and robbery rate from 1992 to 1995. Multiple regressions were used to predict these homicide and robbery rates from a measure of civic engagement (Civicness) assessed during the same period, and from other socioeconomic variables: unemployment, family break up, and geographical characteristics. The predictors explained 77% of the variance among the Italian provinces for robbery, and 61% of the variance for homicide. The predictive patterns were somewhat different for homicide and robbery, but in each case civicness interacted with territorial variables. In the case of homicide, civicness had a preventive impact only in the southern provinces. For robbery, the protective impact was limited to provinces which were urbanized and had large metropolitan areas.     

Invariance of the psychometric function for character recognition across the visual field

The psychometric function for recognition of singly presented digits as a function of digit contrast was measured at 2° steps across the horizontal meridian of the visual field, under monocular and binocular viewing conditions. A maximum-likelihood staircase procedure was used in a 10-alternative forcedchoice recognition paradigm to gather the data. Both the Weibull and the logistic psychometric functions provide excellent fits to the observed data. The slopes of these functions at their point of inflection ranged from 4.0 to 5.0 proportion-correct/log₁₀-unit contrast, for both monocular and binocular viewing and for all loci in the visual field. These slope values correspond to short-term measurements (around 30 trials, or 1 min) and do not include performance variations of longer duration; the latter are estimated to increase slope by a factor of about 1.5. A single psychometric function shape, centered around a threshold value, therefore describes recognition performance at all retinal loci and binocularity. An empirical comparison of slope results across the literature shows that the function’s slope is about twice that reported for a number of detection tasks. The comparison of recognition contrast thresholds, percentage correct values, and other performance measures across studies requires the knowledge of the psychometric function’s slope, and our results thus provide a firm basis for the study of low-contrast character recognition     

Aus dem briefwechsel wilhelm ackermanns

A selection from the correspondence of the logician Wilhelm Ackermann (1896–1962) is presented in this article. The most significant letters were exchanged with Bernays, Scholz and Lorenzen, from which extensive passages are transcribed. Some remarks from other letters, with quotations, are also included.