The variance theory of the mirror effect in recognition memory

The mirror effect refers to a rather general empirical finding showing that, for two classes of stimuli, the class with the higher hit rates also has a lower false alarm rate. In this article, a parsimonious theory is proposed to account for the mirror effect regarding, specifically, high- and low-frequency items and the associated receiver-operating curves. The theory is implemented in a recurrent network in which one layer represents items and the other represents contexts. It is shown that the frequency mirror effect is found in this simple network if the decision is based on counting the number of active nodes in such a way that performance is optimal or near optimal. The optimal performance requires that the number of active nodes is low, only nodes active in the encoded representation are counted, the activation threshold is set between the old and the new distributions, and normalization is based on the variance of the input. Owing to the interference caused by encoding the to-be-recognized item in several preexperimental contexts, the variance of the input to the context layer is greater for highthan for low-frequency items, which yields lower hit rates and higher false alarm rates for high- than for low-frequency items. Although initially the theory was proposed to account for the mirror effect with respect to word frequency, subsequent simulations have shown that the theory also accounts for strength-based mirror effects within a list and between lists. In this case, consistent with experimental data, the variance theory suggests that focusing attention to the more difficult class within a list affects the hit rate, but not the false alarm rate and not the standard deviations of the underlying density, leading to no mirror effect.     

Beyond the gambling paradigm: internal controllability in decision-making.

Much research within decision-making has used the standard gambling paradigm, where decision outcomes depend only on chance. Many real life decisions, however, imply personal control over decision outcomes. This paper addressed the question of how internal controllability influences decision-making. Internal controllability is assumed (i) to enhance unrealistic optimism and (ii) to result in a better cost:benefit ratio. Both tendencies support each other and predict an enhanced attractiveness for internal and controllable choice options. Participants read a scenario and made a decision afterwards. Results supported the prediction: decision-makers take the option they can personally control. This finding widens the narrow perspective inherent in much previous research based on the gambling paradigm.     

Adult age differences in the ability to cope with situations of high arousal in a precision sport

Three field experiments are reported in which skilled miniature golf players varying in age were studied in three types of activities: training, minor competitions, and large competitions. Performance (i.e., number of shots) and arousal (heart rate and subjective ratings of anxiety) measures were registered in all types of activities. The major finding was that the level of performance of older adult players deteriorated in the large competitions, whereas groups of younger adult players, junior players, and youth players performed at the same level in all three events, although all of the groups exhibited a similar increase in arousal from training and minor competitions to large competitions. We suggest that older players may have a deficit in the ability to compensate for the negative effects of nonoptimal levels of arousal because of impairments in a variety of cognitive abilities critical to successful performance.     

Thermographic studies with fluid crystals in peripheral nerve damage

Common peripheral neurogenic lesion in various locations and of different origins were examined thermographically and the results were compared with those obtained by clinical and electromyographic methods. Lesions in the regions of the N. ulnaris and N. medianus can, except in the case of carpal tunnel syndrome, be identified without difficulty by thermography. The results obtained in the case of paresis of the radialis are non-specific, and thermographic examination of radicular lesions are also sometimes ambiguous. Damage in the plexus-brachialis and root region yield impressive results which, however, are not particularly useful.