Vibrotactual choice reaction time,tactile receptor systems and ideomotor compatibility

In most of the literature on human performance the results of an experiment by Leonard (1959) are quoted as the most outstanding example of perfect S-R-compatibility. In that experiment the fingertips were stimulated by a 50 Hz vibration; the vibrating armature had to be depressed and the reaction times of the right index finger were recorded. The reaction time was found not to increase with an increasing number of tactual choices. In experiment 1 of the present study, also applying 50 Hz vibrations, the reaction times of other fingers were also reported. In addition the response stimulus interval (RSI) was varied. Leonard's results were not replicated: reaction time increased with the number of tactual choices at all levels of RSI. In experiment 2 the frequency and amplitude of vibration were systematically varied and it turned out that these variables could account for the differences between the results found. An increase in reaction time with the number of tactual choices was found with weak vibrations, but not with strong vibrations. The differences in reaction time patterns appeared to be caused by differences in tactile receptor systems (i.e. the non-Pacini versus the Pacinian system). It was concluded that the concept of S-R-compatibility did not cover the pattern of results but that the concept of ideomotor compatibility did.     

Psychometric properties of the five facet mindfulness questionnaire in depressed adults and development of a short form

In recent years, there has been a growing interest in therapies that include the learning of mindfulness skills. The 39-item Five Facet Mindfulness Questionnaire (FFMQ) has been developed as a reliable and valid comprehensive instrument for assessing different aspects of mindfulness in community and student samples. In this study, the psychometric properties of the Dutch FFMQ were assessed in a sample of 376 adults with clinically relevant symptoms of depression and anxiety. Construct validity was examined with confirmatory factor analyses and by relating the FFMQ to measures of psychological symptoms, well-being, experiential avoidance, and the personality factors neuroticism and openness to experience. In addition, a 24-item short form of the FFMQ (FFMQ-SF) was developed and assessed in the same sample and cross-validated in an independent sample of patients with fibromyalgia. Confirmatory factor analyses showed acceptable model fit for a correlated five-factor structure of the FFMQ and good model fit for the structure of the FFMQ-SF. The replicability of the five-factor structure of the FFMQ-SF was confirmed in the fibromyalgia sample. Both instruments proved highly sensitive to change. It is concluded that both the FFMQ and the FFMQ-SF are reliable and valid instruments for use in adults with clinically relevant symptoms of depression and anxiety.     

The face of an angel: Effect of exposure to details of moral behavior on facial recognition memory

The Dangerous Decisions Theory (DDT; Porter & ten Brinke, 2009) posits that instantaneous perceptions of trustworthiness based on a stranger's face influence the manner in which ensuing information about the target is processed. This study tested a bi-directional DDT model, proposing that information concerning a target's moral behavior could distort eyewitness memory for the individual's facial trustworthiness. Participants (N = 141) viewed a target individual's face (previously rated as appearing “neutral” on trustworthiness) and then were exposed to one of the three vignettes describing the target's behavior (either immoral, morally neutral, or altruistic). Following a delay, observers were asked to identify the target individual on a facial morph video (continuously ranging in levels of perceived trustworthiness). Results indicated that behavioral information varying in morality influenced facial recognition memory; specifically, faces were recalled as having less trustworthy features following a disclosure of immoral/criminal behavior.     

Personality in proportion: a bipolar proportional scale for personality assessments and its consequences for trait structure

Trait structures resulting from personality assessments on Likert scales are affected by the additive and multiplicative transformations implied in interval scaling and correlational analysis. The effect comes into view on selecting a plausible alternative scale. To this end, we propose a bipolar bounded scale ranging from -1 to +1 representing an underlying process in which the assessor would review and discount positive and negative behavioral instances of a trait. As an appropriate index of likeness between variables X and Y, we propose LXY = SigmaXY/N, the average of the raw scores cross products. Using this index, we carried out a raw scores principal component analysis on data consisting of 133 participants who had each been rated by 5 assessors including self on 914 items. Contrary to the Big-Five structure that was found in these data on standard analysis, the results showed a relatively large first principal component F1 and 2 very small ones, F2 and F3. The sizes LFF=SigmaF2/N, the averages of the squared component scores, were modest to small. It thus appears that the scale, bipolar proportional versus standard, has a profound impact on the size and structure of personality assessments. The dissimilarity remains on analyzing self-ratings rather than averaged (over the 5 assessors) ratings.     

Retrieving the correlation matrix from a truncated PCA solution: The inverse principal component problem

Whenr Principal Components are available fork variables, the correlation matrix is approximated in the least squares sense by the loading matrix times its transpose. The approximation is generally not perfect unlessr =k. In the present paper it is shown that, whenr is at or above the Ledermann bound,r principal components are enough to perfectly reconstruct the correlation matrix, albeit in a way more involved than taking the loading matrix times its transpose. In certain cases just below the Ledermann bound, recovery of the correlation matrix is still possible when the set of all eigenvalues of the correlation matrix is available as additional information.     

A case of extreme simplicity of the core matrix in three-mode principal components analysis

In three-mode Principal Components Analysis, theP ×Q ×R core matrixG can be transformed to simple structure before it is interpreted. It is well-known that, whenP=QR,G can be transformed to the identity matrix, which implies that all elements become equal to values specified a priori. In the present paper it is shown that, whenP=QR − 1,G can be transformed to have nearly all elements equal to values spectified a priori. A cllsed-form solution for this transformation is offered. Theoretical and practical implications of this simple structure transformation ofG are discussed. Constructive comments from anonymous reviewers are gratefully acknowledged.     

A series of lower bounds to the reliability of a test

Two well-known lower bounds to the reliability in classical test theory, Guttman's ₂ and Cronbach's coefficient alpha, are shown to be terms of an infinite series of lower bounds. All terms of this series are equal to the reliability if and only if the test is composed of items which are essentially tau-equivalent. Some practical examples, comparing the first 7 terms of the series, are offered. It appears that the second term (₂) is generally worth-while computing as an improvement of the first term (alpha) whereas going beyond the second term is not worth the computational effort. Possibly an exception should be made for very short tests having widely spread absolute values of covariances between items. The relationship of the series and previous work on lower bound estimates for the reliability is briefly discussed.The authors are obliged to Henk Camstra for providing a computer program that was used in this study.     

Orthogonal procrustes rotation for two or more matrices

Necessary and sufficient conditions for rotating matrices to maximal agreement in the least-squares sense are discussed. A theorem by Fischer and Roppert, which solves the case of two matrices, is given a more straightforward proof. A sufficient condition for a best least-squares fit for more than two matrices is formulated and shown to be not necessary. In addition, necessary conditions suggested by Kristof and Wingersky are shown to be not sufficient. A rotation procedure that is an alternative to the one by Kristof and Wingersky is presented. Upper bounds are derived for determining the extent to which the procedure falls short of attaining the best least-squares fit. The problem of scaling matrices to maximal agreement is discussed. Modifications of Gower's method of generalized Procrustes analysis are suggested.