CUI BONO? A REVIEW OF BREAKING THE SPELL: RELIGION AS A NATURAL PHENOMENON BY DANIEL C. DENNETT

The three requirements for a Darwinian evolutionary process are replication, variation and selection. Dennett (2006) discusses various theories of how these three processes, especially selection, may have operated in the evolution of religion. He believes that the origins of religion, like the origins of language and music, may be approached scientifically. He hopes that such investigations will open a dialog between science and religion leading to moderation of current religious extremism. One problem with Dennett's program, illustrating the difficulty of breaking away from creationist thinking, is Dennett's own failure to consider how Darwinian methods may be used to study evolution of behavioral patterns over the lifetime of individual organisms.     

A counterchange mechanism for the perception of motion

A computational model for the perception of counterchange-specified motion is examined in detail and compared with various versions of the Reichardt motion detection model [Reichardt, W. (1961). Autocorrelation, a principle for the evaluation of sensory information by the central nervous system. In W. A. Rosenblith (Ed.), Sensory communication (pp. 303-317). New York: Wiley]. The counterchange model is composed of a pair of temporally biphasic subunits at two retinal locations, one detecting decreases and the other increases in input activation. Motion is signaled when both subunits are simultaneously excited, as determined by the multiplicative combination of their transient responses. In contrast with the Reichardt detector, which effectively tracks motion energy and accounts solely for results obtained with standard apparent motion stimuli (a surface is visible at one location, then at another), the counterchange model also accounts for the generalized apparent motion perceived between pairs of simultaneously visible surfaces. This indicates that standard apparent motion can be perceived via the same non-sequential, non-motion-energy mechanism as generalized apparent motion. There is no need for either an explicit delay mechanism to account for optimal motion perception at non-zero inter-stimulus intervals, or for inhibitory interaction between subunits to account for the absence of motion in the detector’s null direction (Barlow, H. B., & Levick, W. R., 1965). Both are emergent properties that result from the inhibitory states of the counterchange detector’s biphasic subunits. In addition to apparent motion, the counterchange principle potentially accounts for the perception of motion for drifting gratings, the short range motion perceived for random-dot cinematograms, and the motion perceived for continuously moving objects.     

The relationship between illness perceptions and panic in chronic obstructive pulmonary disease

BackgroundElevated levels of anxiety and panic are common in respiratory disease. To date the cognitive-behavioural model of panic has been utilised to help explain and manage panic in respiratory disease. This cross-sectional study investigated the relationship between illness perceptions and panic in chronic obstructive pulmonary disease (COPD) within a self-regulatory framework of adaptation to physical illness.MethodsFifty-nine participants with COPD completed questionnaires measuring illness perceptions, anxiety and depression, frequency and severity of panic attacks and impact of disease on daily life and well-being. The percent forced expiratory volume in the first second (FEV₁%) was used as an objective measure of lung function.ResultsHigh levels of clinical anxiety and depression were reported (35% and 19% respectively). Sixty-three percent of participants reported experiencing a panic attack during the previous year and of these 51% during the previous month. Panic was unrelated to level of disease severity. Specific illness perceptions (beliefs relating to illness identity, timeline, consequences and emotional representations) were important in differentiating between panickers and non-panickers.ConclusionsThe results highlight the importance of assessing illness perceptions within the framework of the self-regulatory model to provide an additional theoretical perspective for investigating and managing panic in chronic respiratory disease.     

Significance Testing with No Alternative Hypothesis: A Measure of Surprise

A pure significance test would check the agreement of a statistical model with the observed data even when no alternative model was available. The paper proposes the use of a modified p-value to make such a test. The model will be rejected if something surprising is observed (relative to what else might have been observed). It is shown that the relation between this measure of surprise (the s-value) and the surprise indices of Weaver and Good is similar to the relationship between a p-value, a corresponding odds-ratio, and a logit or log-odds statistic. The s-value is always larger than the corresponding p-value, and is not uniformly distributed. Difficulties with the whole approach are discussed.