Additive factors analysis of inhibitory processing in the stop-signal paradigm

This article reports an additive factors analysis of choice reaction and selective stop processes manipulated in a stop-signal paradigm. Three experiments were performed in which stimulus discriminability (SD) and stimulus-response compatibility (SRC) were manipulated in a factorial fashion. In each experiment, the effects of SD and SRC were assessed first for going and next for stopping. Two experiments yielded the anticipated additive relation between SD and SRC for going but stopping appeared to be insensitive to the SD manipulation. Increasing the SD demands in the third experiment by using a different display resulted in a significant (over-additive) interaction between SD and SRC for going and a non-significant (under-additive) interaction for stopping. The pattern of results that emerged from this set of experiments was interpreted to suggest that going and stopping are both similar and different. They are similar in that distinct stages can be identified in both going and stopping but they are also different, as selective stopping seems to be less sensitive to discrimination manipulations relative to going.     

Measuring the multidimensional self-concept and global self-worth of 6- to 8-year-olds

A downward extension of a Dutch version of Harter's Self-Perception Profile for Children (SPPC) was tested in a Flemish sample of 880 1st to 3rd graders (Mage = 7.18 years, SD = 0.80). In 2nd and 3rd graders, 5 SPPC factors were identified; in 1st graders only 4 were identified. Support was found for the equivalence of structure and measurement for 2nd and 3rd grades and for boys and girls. Most scales possessed reasonable to good internal consistency for these groups. The results support the multidimensionality of self-concept responses for young children and the improving of the distinctiveness of SPPC factors with age. Young children seem to have an ability to verbalize concepts of their global self-worth that can be tapped by self-report measures.     

Empirical evaluation of the MCMI-III personality disorder scales

The MCMI-III personality disorder scales were empirically validated with a sample of 870 clinical patients and inmates. Prevalence rates of personality disorders were in general lower on the MCMI-III than clinical ratings, but trait prevalence was generally higher; thus a base rate of 75 on the MCMI-III could be a guideline in the screening of trait prevalence. However, the sensitivity of some MCMI-III scales was very low. Moreover, the correlations of most personality disorder scales of the MCMI-III were significant and positive with corresponding measures on clinical ratings and MMPI-2 personality disorder scales, but these were, in general, not significantly higher than some other correlations. As a consequence the discriminant validity seems to be questionable. The MCMI-III alone cannot be used as a diagnostic inventory, but the test could be useful as a screening device as a part of a multimethod approach that allows aggregation over measures in making diagnostic decisions.     

Influence of instruction on velocity and accuracy of overarm throwing

This study investigated the influence of instruction on the ball velocity and accuracy of a goal-directed overarm throw. 9 experienced Norwegian male team handball players executed a throwing task randomly seven times under 5 different instructions varying from emphasizing speed to accuracy. When instructions increasingly emphasized accuracy, velocity decreased. However, accuracy did not improve when subjects were instructed to focus on it. A possible explanation for this finding could lie in the specific subject group. The subjects were highly experienced team handball players with an average of 12 years in the sport. Thus, the accuracy they demonstrated at high velocity might actually be already extremely high and difficult to improve upon when reducing throwing velocity. Further, the velocity of throwing when instruction emphasized accuracy was approximately 85% of the maximal velocity, indicating that experienced team handball players are trained to throw accurately at relatively high velocity.     

The Guilty Knowledge Test and the modified Stroop task in detection of deception: an exploratory study

The current study tested whether a simple Stroop paradigm can be used to detect deceptive behavior. 40 university students (34 women), half of whom committed a mock crime, were administered a Guilty Knowledge Test and modified Stroop task to detect guilt or innocence. The Guilty Knowledge Test is a well-known psychophysiological detection method, which consists of multiple-choice questions about details of the crime while skin conductance is recorded. Subjects possessing guilty knowledge are expected to show enhanced differential responses to the relevant stimuli. The modified Stroop task required color-naming of colored words related to the mock crime or an irrelevant crime. Each version of the Stroop task was presented in story form. Subjects possessing guilty knowledge were expected to produce larger reaction times to the relevant version relative to the irrelevant version. The test correctly identified 100% of innocent participants and 78% of guilty participants. In contrast, Stroop interference. i.e., reaction times for irrelevant crime details subtracted from those for mock crime details, did not differentiate between the two groups, suggesting that the story form of the Stroop paradigm is not suitable for lie detection.     

Convergent validity of the MCMI-III personality disorder scales and the MMPI-2 scales

The MCMI-III personality disorder scales (Millon, 1994) were empirically validated in a sample of prisoners, psychiatric inpatients, and outpatients (N = 477). The scale intercorrelations were congruent with those obtained by Millon, Davis, and Millon (1997). We conclude that our Flemish/Dutch version shows no significant differences with the original version of the MCMI-III as far as intercorrelations are concerned. Convergent validity of the MCMI-III personality disorder scales was evaluated by the correlational data between the MCMI-III personality disorder scales and the MMPI-2 clinical (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) and personality disorder (Somwaru & Ben-Porath, 1995) scales. Improved convergence was obtained compared with previous versions of the MCMI-I. Only the compulsive MCMI-III personality disorder scale remains problematic. The scale even showed negative correlations with some of the related clinical scales and with the corresponding personality disorder scales of the MMPI-2.     

Electrophysiological correlates of anterior cingulate function in a go/no-go task: Effects of response conflict and trial type frequency

Neuroimaging and computational modeling studies have led to the suggestion that response conflict monitoring by the anterior cingulate cortex plays a key role in cognitive control. For example, response conflict is high when a response must be withheld (no-go) in contexts in which there is a prepotent tendency to make an overt (go) response. An event-related brain potential (ERP) component, the N2, is more pronounced on no-go than on go trials and was previously thought to reflect the need to inhibit the go response. However, the N2 may instead reflect the high degree of response conflict on no-go trials. If so, an N2 should also be apparent when subjects make a go response in conditions in which nogo events are more common. To test this hypothesis, we collected high-density ERP data from subjects performing a go/no-go task, in which the relative frequency of go versus no-go stimuli was varied. Consistent with our hypothesis, an N2 was apparent on both go and no-go trials and showed the properties expected of an ERP measure of conflict detection on correct trials: (1) It was enhanced for low-frequency stimuli, irrespective of whether these stimuli were associated with generating or suppressing a response, and (2) it was localized to the anterior cingulate cortex. This suggests that previous conceptions of the no-go N2 as indexing response inhibition may be in need of revision. Instead, the results are consistent with the view that the N2 in go/no-go tasks reflects conflict arising from competition between the execution and the inhibition of a single response.     

Large-scale ensemble averaging of ambulatory impedance cardiograms

Impedance cardiography has been used increasingly to measure human physiological responses to emotional and mentally engaging stimuli. The validity of large-scale ensemble averaging of ambulatory impedance cardiograms was evaluated for preejection period (PEP), interbeat interval, and dZ/dt_(min) amplitude. We tested whether the average of “classical” 60-sec ensemble averages across periods with fixed activity, posture, physical load, social situation, and location could be accurately estimated from a single large-scale ensemble average spanning these entire periods. Impedance and electrocardiograms were recorded for about 24-h from 21 subjects. Recordings were scored by seven raters, using both methods for each subject. Good agreement (average intraclass correlation coefficient was .91) between both ensemble averaging methods was found for all three cardiac function measures. The results indicate that for unambiguous ambulatory impedance cardiograms, large-scale ensemble averaging is valid, which makes measuring prolonged changes in cardiac sympathetic activity by measuring ambulatory PEP feasible even in large epidemiological samples.     

The role of the centre of projection in the estimation of slant from texture of planar surfaces

Displays were presented consisting of a perspective projection of a regular square grid, made up of vertical and horizontal equally spaced white lines, that was slanted in depth. The surface was viewed monocularly, through a circular aperture. A range of slants was shown (0 degree, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, or 60 degrees) and the observers' task was to match the slant by means of a mouse-driven probe. The viewing distance (50, 75, or 100 cm) as well as the focal distance (25, 50, 75, 100, or 125 cm) were varied. We expected the estimation error to be smallest when the viewing distance and the focal distance coincided. This was not the case. Instead, subjects seemed to use the perspective deformation of the texture elements in the stimulus display to make a slant estimation, regardless of the specific combination of viewing distance and focal distance.     

The Morality System with and without God

What I set out to do is to cast some doubt on the thesis that, in Bernard Williams's words, any appeal to God in morality either adds nothing at all, or it adds the wrong sort of thing. A first conclusion is that a morality of real, inescapable and (sometimes) for the agent costly obligations, while being at home in a theistic metaphysic, does not sit easily with metaphysical, atheistic naturalism. The second conclusion is that Christine Korsgaard's impressive ethical project which is neutral towards theism and atheism fails in giving a satisfying account of such obligations. My final claim is that a theistic account in terms of a strong divine command theory might succeed where non- and atheistic accounts seem to founder.