Some problems with cost-benefit analysis in health care

...Arnold's article is very ambitious. He suggests rules that could be followed in order to decide whether health care should be rationed. He notes that explicit assessments of costs and benefits using the same monetary unit are rarely used. The main reason, it seems to me, is that the method of cost-benefit analysis is relatively difficult to apply in the context of health care. Arnold does not address the difficulties that are related to his approach. Thus, my impression is that the interest of his provocative article lies more in its ability to foster a useful debate than in the methodology itself. In this brief commentary, I will merely list some of the theoretical problems that occurred to me while reading this article....     

Age-related changes in processing auditory stimuli during visual attention: evidence for deficits in inhibitory control and sensory memory.

Age-related declines in attention and cognition have been associated with a difficulty in inhibiting the processing of task-irrelevant information (i.e., the inhibitory deficit hypothesis). However, evidence supporting the inhibitory deficit hypothesis remains equivocal, in part because of complexities in examining the processing of irrelevant stimuli using purely behavioral techniques. The effects of age on the processing of task-irrelevant stimuli were examined using scalp-recorded event-related brain potentials. Participants performed a visual discrimination task while standard and deviant auditory stimuli were presented in the background. Deviant auditory stimuli generated a mismatch negativity (MMN) wave that decreased with age, in part because of an age-related enhancement in sensory-evoked responses. The age-related changes in processing task-irrelevant auditory stimuli are consistent with the inhibitory deficit hypothesis and suggest that impaired inhibitory control of sensory input may play a role in the age-related declines in performance during selective attention tasks.     

Logic or rhetoric in law?

One of the most crucial questions in the philosophy of law deals with the very nature of legal reasoning. Does this reasoning belong to logic or to rhetoric? This debate, increasingly centered on rhetoric, is not merely a question of language use; it covers and indicates a more basic choice between formal legalism — focusing on rational deduction from the law — and pragmatic judiciarism — focusing on reasonable debate in the court. Today, it is necessary to circumscribe the respective fields of logic and rhetoric in the language of law, while showing how they are sometimes complementary in the resolution of legal problems. But, even when we have acknowledged the need for a rhetoric accompanied by logic, we have to define that rhetoric cautiously. I confront a narrow rhetoric, often called argumentation, with a wider one of interrogative nature. There are two conceptions of rationality at stake. Their comparison enables us to raise the question of the foundation of law, as a locus to use arguments, as well as to solve social problems.     

Can subthreshold summation be observed with the Ehrenstein illusion?

Subthreshold summation between physical target lines and illusory contours induced by edges such as those produced in the Kanizsa illusion has been reported in previous studies. Here, we investigated the ability of line-induced illusory contours, using Ehrenstein figures, to produce similar subthreshold summation. In the first experiment, three stimulus conditions were presented. The target line was superimposed on the illusory contour of a four-arm Ehrenstein figure, or the target was presented between two dots (which replaced the arms of the Ehrenstein figure), or the target was presented on an otherwise blank screen (control). Detection of the target line was significantly worse when presented on the illusory contour (on the Ehrenstein figure) than when presented between two dots. This result was consistent for both curved and straight target lines, as well as for a 100 ms presentation duration and unlimited presentation duration. Performance was worst in the control condition. The results for the three stimulus conditions were replicated in a second experiment in which an eight-arm Ehrenstein figure was used to produce a stronger and less ambiguous illusory contour. In the third experiment, the target was either superimposed on the illusory contour, or was located across the central gap (illusory surface) of the Ehrenstein figure, collinear with two arms of the figure. As in the first two experiments, the target was either presented on the Ehrenstein figure, or between dots, or on a blank screen. Detection was better in the dot condition than in the Ehrenstein condition, regardless of whether the target was presented on the illusory contour or collinear with the arms of the Ehrenstein figure. These three experiments demonstrate the ability of reduced spatial uncertainty to facilitate the detection of a target line, but do not provide any evidence for subthreshold summation between a physical target line and the illusory contours produced by an Ehrenstein figure. The incongruence of these results with previous findings on Kanizsa figures is discussed.     

CANTAB explicit memory is less impaired in addicted schizophrenia patients

It has been suggested that in order to sustain the lifestyle of substance abuse, addicted schizophrenia patients would have less negative symptoms, better social skills, and less cognitive impairments. Mounting evidence supports the first two assumptions, but data lack regarding cognition in dual diagnosis schizophrenia. Seventy-six schizophrenia outpatients (DSM-IV) were divided into two groups: with (n = 44) and without (n = 32) a substance use disorder. Motor speed and visuo-spatial explicit memory were investigated using CANTAB. As expected, dual diagnosis patients showed a better cognitive performance. Our results suggest either that substance abuse relieves the cognitive deficits of schizophrenia or that the patients with less cognitive deficits are more prone to substance abuse.     

Effects of visual attentional load on low-level auditory scene analysis

The sharing of processing resources between the senses was investigated by examining the effects of visual task load on auditory event-related brain potentials (ERPs). In Experiment 1, participants completed both a zero-back and a one-back visual task while a tone pattern or a harmonic series was presented. N1 and P2 waves were modulated by visual task difficulty, but neither mismatch negativity (MMN) elicited by deviant stimuli from the tone pattern nor object-related negativity (ORN) elicited by mistuning from the harmonic series was affected. In Experiment 2, participants responded to identity (what) or location (where) in vision, while ignoring sounds alternating in either pitch (what) or location (where). Auditory ERP modulations were consistent with task difficulty, rather than with task specificity. In Experiment 3, we investigated auditory ERP generation under conditions of no visual task. The results are discussed with respect to a distinction between process-general (N1 and P2) and processspecific (MMN and ORN) auditory ERPs.     

Catastrophe theory and its critics

Catastrophe theory has been sharply criticized because it does not seem to have practical applications nor does it seem to allow us to increase our power over Nature. I want to rehabilitate the theory by foregoing the controversy raised by scientists about its practical efficiency. After a short exposition of the theory's mathematical formalism and a detailed analysis of the main objections that have been raised against it, I argue that theory is not only to be judged on its practical results, which are in fact limited, but also on its epistemological and philosophical implications. Catastrophe theory indeed represents a real revolution in science: it announces the coming of a more theoretical, less practical, science, having more to do with understanding reality than with acting on it, and, from that point of view, it may be considered as the modern philosophy of Nature.     

Positive and negative instructions in symbolic paired comparisons with the months of the year

Summary We investigated the semantic interpretation of positive (MORE THAN) and negative (LESS THAN) instructions in a symbolic paired comparison task with an overlearned and finite series of stimuli. French-speaking subjects were asked to indicate which member of month pairs occurred PLUS TOT (earlier), PLUS TARD (later), MOINS TOT (less early), or MOINS TARD (less late) in the year. In Experiment 1, the sign of the comparative instruction (MORE vs. LESS) was kept constant, while its attribute (EARLY vs. LATE) varied. In Experiment 2, the attribute of the instruction was kept constant, while its sign varied. The main results indicate that (1) negative instructions (with adverb LESS) yielded longer response latencies than positive ones (with adverb MORE); this difference was particularly salient on the first experimental session but, on subsequent sessions, it was reduced in Experiment 1 and neutralized in Experiment 2; (2) a symbolic-distance effect was observed on response latency and response accuracy with the four forms of the comparative instruction; (3) violations of monotonicity were noted in the symbolic-distance effect when June was used as a reference month in the analysis; (4) the serial-position effect had the form of a double-bowed curve with three stable anchor points around January, June, and December; and (5) the pattern of semantic-congruity effect with negative instructions was the exact reversal of that obtained with positive instructions; that is, if the month pairs occurred early in the year, response latencies were shorter with the instruction less late than with less early, whereas if the month pairs occurred late in the year response latencies were shorter with instruction "less early than with less late. The theoretical implications of these results for Banks' Semantic-coding model and Holyoak's Reference-point model are discussed.     

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