An n-back task using vibrotactile stimulation with comparison to an auditory analogue

We report a vibrotactile version of the common n-back task used to study working memory. Subjects wore vibrotactile stimulators on three fingers of one hand, and they responded by pressing a button with the other hand whenever the current finger matched the one stimulated n items back. Experiment 1 showed a steep decline in performance as n increased from 1 to 3; each additional level ofn decreased performance by 1.5 d' units on average. Experiment 2 supported a central capacity locus for the vibrotactile task by showing that it correlated strongly with an auditory analogue; both tasks were also related to standard digit span. The vibrotactile version of n-back may be particularly useful in dual-task contexts. It allows the assessment of cognitive capacity in sensory-impaired populations in which touch remains intact, and it may find use in brain-imaging studies in which vibrotactile stimuli impose a memory load.     

An Impossibility Theorem on Beliefs in Games

A paradox of self-reference in beliefs in games is identified, which yields a game-theoretic impossibility theorem akin to Russell’s Paradox. An informal version of the paradox is that the following configuration of beliefs is impossible:Ann believes that Bob assumes thatAnn believes that Bob’s assumption is wrongThis is formalized to show that any belief model of a certain kind must have a ‘hole.’ An interpretation of the result is that if the analyst’s tools are available to the players in a game, then there are statements that the players can think about but cannot assume. Connections are made to some questions in the foundations of game theory.Special Issue Ways of Worlds II. On Possible Worlds and Related Notions Edited by Vincent F. Hendricks and Stig Andur Pedersen     

A reappraisal of medieval mysticism & hysteria

This paper examines the historical association between medieval mysticism and asceticism and the psychopathological condition of hysteria. We first review the particular forms of medieval mysticism and asceticism that seem to have inspired modern psychiatrists and reductive historians to dismiss these phenomena as indubitably neurotic behaviours. Then we review the concept of hysteria as it evolved during the last two centuries for points of convergence with mysticism. Finally, we question the validity of value-laden diagnostic formulations in the domain of personality assessment. A few highly dramatic but culturally endorsed religious behaviours occuring in an otherwise well functioning individual does not constitute a basis for any psychiatric diagnosis, let alone a condemnatory characterological one such as hysteria. We propose a perspective for looking at medieval mystical states of mind and behaviours in context that moves beyond ahistoric assumptions that employ modern Western standards as the yardstick for medieval health and illness.     

The effect of perceived distance on perceived movement

Equations were developed to predict the apparent motion of a physically stationary object resulting from head movement as a function of errors in the perceived distances of the object or of its parts. These equations, which specify the apparent motion in terms of relative and common components, were applied to the results of two experiments. In the experiments, the perceived slant of an object was varied with respect to its physical slant by means of perspective cues. In Experiment I, O reported the apparent motion and apparent distance of each end of the object independently. The results are consistent with the equations in terms of apparent relative motion, but not in terms of apparent common motion. The latter results are attributed to the tendency for apparent relative motion to dominate apparent common motion when both are present simultaneously. In Experiment II, a direct report of apparent relative motion (in this case, apparent rotation) was obtained for illusory slants of a physically frontoparallel object. It was found that apparent rotations in the predicted direction occurred as a result of head motion, even though under these conditions no rotary motion was present on the retina.     

Sex differences in judgement of facial affect: a multivariate analysis of recognition errors

The present paper investigated recognition errors in affective judgement of facial emotional expressions. Twenty-eight females and sixteen males participated in the study. The results showed that in both males and females emotional displays could be correctly classified, but females had a higher rate of correct classification; males were more likely to have difficulty distinguishing one emotion from another. Females rated emotions identically regardless of whether the emotion was displayed by a male or female face. Furthermore, the two-factor structure of emotion, based on a valence and an arousal dimension, was only present for female subjects. These results further extend our knowledge about gender differences in affective information processing.     

Stability/Instability of Cognitive Strategies Across Tasks Determine Whether Stress Will Affect Judgmental Processes'

Previous research indicates that individuals employ various cognitive heuristics and decision modes in making decisions and judgmental tasks that do not follow an expected value model. It further indicates that several cognitive faculties are affected by stress. The purpose of this study was twofold: first, to examine whether individual differences exist in the use of cognitive heuristics and risk-assessment decision modes; second, to examine whether stress would affect the use of these cognitive strategies. Three versions of a questionnaire measuring the representativeness and availability heuristics, and risk-seeking and risk-aversion decision modes were administered to three different groups of subjects. Consistent individual differences were only observed in the subscales measuring risk-seeking and risk-aversion modes, but not in the use of the heuristics. In a different group of subjects, exposure to noise and task overload stress increased the use of the representativeness heuristic, but did not alter the use of risk-seeking and risk-aversion decision modes. These results indicate that the existence of individual differences in cognitive strategies may determine, in part, whether stress will modify judgmental processes.     

Sex differences in social memory among preschool children

Preschool children, 17 boys and 18 girls, attending a day-care center, were presented with photographs of all 37 children in the center and required to supply the name of each pictured child. Girls made significantly fewer errors in identification than boys (p<.05), although boys spent more time in the day-care program (p<.025). Girls were, on the average, 4 months older than boys (p<.01), but age was not significantly correlated with number of identification errors. No sex differences were obtained on the Peabody Picture Vocabulary Test, memory, or perceptual-performance scales of the McCarthy Scales of Children's Abilities. Results were consistent with previous findings for college students and were interpreted in terms of differential child-rearing practices and observational learning.This research was supported by Grant 216-15-36 from the Cooperative State Research Service, U. S. Department of Agriculture, to the University of Maryland, Eastern Shore.     

Overt naming fMRI pre- and post-TMS: Two nonfluent aphasia patients, with and without improved naming post-TMS

Two chronic, nonfluent aphasia patients participated in overt naming fMRI scans, pre- and post-a series of repetitive transcranial magnetic stimulation (rTMS) treatments as part of a TMS study to improve naming. Each patient received 10, 1-Hz rTMS treatments to suppress a part of R pars triangularis. P1 was a ‘good responder’ with improved naming and phrase length; P2 was a ‘poor responder’ without improved naming.Pre-TMS (10 years poststroke), P1 had significant activation in R and L sensorimotor cortex, R IFG, and in both L and R SMA during overt naming fMRI (28% pictures named). At 3 mo. post-TMS (42% named), P1 showed continued activation in R and L sensorimotor cortex, R IFG, and in R and L SMA. At 16 mo. post-TMS (58% named), he also showed significant activation in R and L sensorimotor cortex mouth and R IFG. He now showed a significant increase in activation in the L SMA compared to pre-TMS and at 3 mo. post-TMS (p < .02; p < .05, respectively). At 16 mo. there was also greater activation in L than R SMA (p < .08). At 46 mo. post-TMS (42% named), this new LH pattern of activation continued. He improved on the Boston Naming Test from 11 pictures named pre-TMS, to scores ranging from 14 to 18 pictures, post-TMS (2–43 mo. post-TMS). His longest phrase length (Cookie Theft picture) improved from three words pre-TMS, to 5–6 words post-TMS.Pre-TMS (1.5 years poststroke), P2 had significant activation in R IFG (3% pictures named). At 3 and 6 mo. post-TMS, there was no longer significant activation in R IFG, but significant activation was present in R sensorimotor cortex. On all three fMRI scans, P2 had significant activation in both the L and R SMA. There was no new, lasting perilesional LH activation across sessions for this patient. Over time, there was little or no change in his activation. His naming remained only at 1–2 pictures during all three fMRI scans. His BNT score and longest phrase length remained at one word, post-TMS.Lesion site may play a role in each patient’s fMRI activation pattern and response to TMS treatment. P2, the poor responder, had an atypical frontal lesion in the L motor and premotor cortex that extended high, near brain vertex, with deep white matter lesion near L SMA. P2 also had frontal lesion in the posterior middle frontal gyrus, an area important for naming (Duffau et al., 2003); P1 did not. Additionally, P2 had lesion inferior and posterior to Wernicke’s area, in parts of BA 21 and 37, whereas P1 did not.The fMRI data of our patient who had good response following TMS support the notion that restoration of the LH language network is linked in part, to better recovery of naming and phrase length in nonfluent aphasia.     

Stop that! Inhibition,sensitization, and their neurovisceral concomitants

There is increasing evidence that the behavior of living systems can be conceptualized as a self-organizing dynamical system. Moreover, evidence suggests that inhibitory processes give these systems the flexibility that is necessary for efficient functioning in the face of changing environmental demands. The process of sensitization can be conceived as a breakdown of inhibitory neural processes that can lead to maladaptive, perseverative behavior. In this paper we describe a model of inhibition and sensitization from a dynamical systems perspective. We show that inhibition is important for adaptive behavior across a number of levels of system functioning. Using our work on attention, emotion, and anxiety disorders we show the importance of both central - for example gamma-aminobutyric acid (GABA)-ergic - and peripheral - for example heart rate variability (HRV) - inhibitory processes and how they may be linked by a network of neural structures that guide the organism from one state of relative stability to another.