Background. Signal detection theory (SDT) describes how respondents categorize ambiguous stimuli over repeated trials. It measures separately “discrimination” (ability to recognize a signal amid noise) and “criterion” (inclination to respond “signal” v. “noise”). This is important because respondents may produce the same accuracy rate for different reasons. We employed SDT to measure the referral decision making of general practitioners (GPs) in cases of possible lung cancer. Methods. We constructed 44 vignettes of patients for whom lung cancer could be considered and estimated their 1-year risk. Under UK risk-based guidelines, half of the vignettes required urgent referral. We recruited 216 GPs from practices across England. Practices differed in the positive predictive value (PPV) of their urgent referrals (chance of referrals identifying cancer) and the sensitivity (chance of cancer patients being picked up via urgent referral from their practice). Participants saw the vignettes online and indicated whether they would refer each patient urgently or not. We calculated each GP’s discrimination (d ′) and criterion (c) and regressed these on practice PPV and sensitivity, as well as on GP experience and gender. Results. Criterion was associated with practice PPV: as PPV increased, GPs’c also increased, indicating lower inclination to refer (b = 0.06 [0.02–0.09]; P = 0.001). Female GPs were more inclined to refer than male GPs (b = −0.20 [−0.40 to −0.001]; P = 0.049). Average discrimination was modest (d′ = 0.77), highly variable (range, −0.28 to 1.91), and not associated with practice referral performance. Conclusions. High referral PPV at the organizational level indicates GPs’ inclination to avoid false positives, not better discrimination. Rather than bluntly mandating increases in practice PPV via more referrals, it is necessary to increase discrimination by improving the evidence base for cancer referral decisions.

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Human Mirror Neuron SystemTraits of Autism in the normal population Sensorimotor reactivity a b s t r a c t Previous research suggested that EEG markers of mirror neuron system activation may differ, in the normal population as a function of different levels of the autistic spectrum quotient; (AQ). The present study aimed at modulating the EEG sensorimotor reactivity induced by hand movement observation by means of repetitive transcranial magnetic stimulation (rTMS) applied to the inferior parietal lobule. We examined how the resulting rTMS modulation differed in relation to the self-reported autistic traits in the typically developing population.Results showed that during sham stimulation, all participants had significantly greater sensorimotor alpha reactivity (motor cortex-C electrodes) when observing hand movements compared to static hands. This sensorimotor alpha reactivity difference was reduced during active rTMS stimulation. Results also revealed that in the average AQ group at sham there was a significant increase in low beta during hand movement than static hand observation (pre-motor areas-FC electrodes) and that (like alpha over the C electrodes) this difference is abolished when active rTMS is delivered. Participants with high AQ scores showed no significant difference in low beta sensorimotor reactivity between active and sham rTMS during static hand or hand movement observation. These findings suggest that unlike sham, active rTMS over the IPL modulates the oscillatory activity of the low beta frequency of a distal area, namely the anterior sector of the sensorimotor cortex, when participants observe videos of static hand. Importantly, this modulation differs according to the degree of self-reported traits of autism in a typically developing population.& 2013 Elsevier B.V. All rights reserved. b r a i n r e s e a r c h ]Please cite this article as: Puzzo, I., et al., The effect of rTMS over the inferior parietal lobule on EEG sensorimotor reactivity differs according to self-reported traits of autism in typically developing individuals. Brain Research (2013), http://dx

The somatic marker hypothesis (SMH) is one of the more dominant physiological models of human decision making and yet is seldom applied to decision making in financial investment scenarios. This study provides preliminary evidence about the application of the SMH in investment choices using heart rate (HR) and skin conductance response (SCRs) measures. Twenty undergraduate students were split equally into expert (defined by familiarity with investments) and novice (no familiarity) groups-previous research has associated expertise with cognitive differences in decision making scenarios. Both completed the BART and BIAS-a computerized simulation of real trading scenariostasks as assessments of investment decision making in conditions of low vs high uncertainty, as defined by the Bayesian Calculation (level of certainty is more than:(1-(-300%)) / ((300%-(-300%)) = 66.67% (0.67). Results suggest that, whilst primary inducers (innate physiological responses) support and guide optimal decision making in conditions of uncertainty, secondary inducers (physiological responses dependent on memory/experience) moderate this effect i.e. the stressful thoughts that accompany the task restrict optimal decision making. This study contributes to the current knowledge on why emotions in finance can lead people to suboptimal decisions.

In an endogenous cueing paradigm with central visual cues, observers made speeded responses to tactile targets at the hands, which were either close together or far apart, and holding either two separate objects or one common object between them. When the hands were far apart, the response time costs associated with attending to the wrong hand were reduced when attention had to be shifted along one object jointly held by both hands compared to when it was shifted over the same distance but across separate objects. Similar reductions in attentional costs were observed when the hands were placed closer together, suggesting that processing at one hand is less prioritised over that at another when the hands can be 'grouped' by virtue of arising from the same spatial location or from the same object.Probes of perceived hand locations throughout the task showed that holding a common object decreased attentional separability without decreasing the perceived separation between the hands. Our findings suggest that tactile events at the hands may be represented in a spatial framework that flexibly adapts to (object-guided) attentional demands, while their relative coordinates are simultaneously preserved.

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