The effect of white-noise mask level on sinewave contrast detection thresholds and the critical-band-masking model

It is known that visual noise added to sinusoidal gratings changes the typical U-shaped threshold curve which becomes flat in log-log scale for frequencies below 10c/deg when gratings are masked with white noise of high power spectral density level. These results have been explained using the critical-band-masking (CBM) model by supposing a visual filter-bank of constant relative bandwidth. However, some psychophysical and biological data support the idea of variable octave bandwidth. The CBM model has been used here to explain the progressive change of threshold curves with the noise mask level and to estimate the bandwidth of visual filters. Bayesian staircases were used in a 2IFC paradigm to measure contrast thresholds of horizontal sinusoidal gratings (0.25-8 c/deg) within a fixed Gaussian window and masked with one-dimensional, static, broadband white noise with each of five power density levels. Raw data showed that the contrast threshold curve progressively shifts upward and flattens out as the mask noise level increases. Theoretical thresholds from the CBM model were fitted simultaneously to the data at all five noise levels using visual filters with log-Gaussian gain functions. If we assume a fixed-channel detection model, the best fit was obtained when the octave bandwidth of visual filters decreases as a function of peak spatial frequency.     

Recurrent criminal behavior and executive dysfunction

OBJECTIVE: To experimentally test the hypothesis that people who repeatedly participate in forms of non-violent crime exhibit an executive deficit detected in tests of high ecological validity, having changes in prefrontal functioning as neurophysiologic basis. PARTICIPANTS AND METHODS: A batteiy to assess executive dysfunction was administered--the Behavioural Assessment of the Dysexecutive Syndrome (BADS)--to an experimental group of 30 inmates convicted of crimes against property (mean age = 39.3, SD = 9.98), and a control group of 30 (mean age = 32.7, SD = 11.8), all male. RESULTS: The group of recurrent inmates performed significantly worse than the control group in their global scores on the battery, as well as in the majority of subscales. CONCLUSION: Without removing from consideration the fact that sample size was not very large and, primarily, alerting ourselves to the dangerous hypothesis of a "frontal criminogenesis," the authors interpret criminal recurrence and resistance to penal measures in terms of the scarcity of control that individuals from the experimental group have over their behavior and its respective consequences.     

Enhancing recognition memory in adults through differential outcomes

It has been widely demonstrated that the differential outcomes procedure (DOP) facilitates both the learning of conditional relationships and the memory for the conditional stimuli in animal subjects. For conditional discriminations in humans, the DOP also produces an increase in the speed of acquisition and/or final accuracy. However, the potential facilitative effects of differential outcomes in human memory have not been fully assessed. In the present study, we aimed to test whether this procedure improves performance on a recognition memory task in healthy adults. Participants showed significantly better delayed face recognition when differential outcomes were used. This novel finding is discussed in the light of other studies on the differential outcomes effect (DOE) in both animals and humans, and implications for future research are presented.     

Structural gender differences in perceived social support

Gender is an important influence on support-relevant social interactions, however findings of studies on gender differences in social support are not definitive. Although differences between men and women in the various social support measures have been found in numerous studies, neither the cause nor the explanatory process is known. This study examines gender differences in the dimensionality of social support. A large sample (N=3210) from the general population of women (60%) and men aged between 18 and 65 years old (Mean AGE=34.1) responded to a brief scale with items assessing the distinct functions of the perceived availability of social support. Confirmatory factor analyses yielded one factor in the women's sample that measures global social support perceived, and two in the men's. The first factor in the men's sample measures emotional support (providing empathy, caring, validation of self-worth), and the second measures instrumental support (e.g. practical assistance or financial aid). We concluded that there are gender differences in the structure of perceived social support and that these differences can be explained by socialization experiences and social roles associated with gender.     

Nietzsche and the tradition 1

Nietzsche and Modern Times: A study of Bacon, Descartes and Nietzsche. Laurence Lampert. New Haven: Yale University Press, 1993. Pp. xii + 475. £35.00

Nietzsche and Metaphysics. Peter Poellner. Oxford: Clarendon Press, 1995. Pp. xi + 320.     

suspicion of sudden infant death syndrome & injuries to infants: the effects of type of death certifier,training, and economics

This paper examines the level of suspicion by death certifiers when ruling infant deaths as accidents. Data were gathered on economic factors, amount of training in death investigation received, and personal characteristics for 1995 from 776 medical examiners or coroners. Findings indicate that personal and social factors such as age, education, and population have negligible or no effects on the level of suspicion held by death certifiers in manner of death rulings for infants. The findings from this study do suggest there is potential for inaccurate rulings of infant death due to lack of training, education, and economic resources depending on the events surrounding an infant's death and whether the death certifier is a coroner or medical examiner.     

Ampliative Transmission and Deontological Internalism

Deontological internalism is the family of views where justification is a positive deontological appraisal of someone's epistemic agency: S is justified, that is, when S is blameless, praiseworthy, or responsible in believing that p. Brian Weatherson discusses very briefly how a plausible principle of ampliative transmission reveals a worry for versions of deontological internalism formulated in terms of epistemic blame. Weatherson denies, however, that similar principles reveal similar worries for other versions. I disagree. In this article, I argue that plausible principles of ampliative transmission reveal a worry for deontological internalism in general.