A comparison of the classification capabilities of the 1-dimensional kohonen neural network with two pratitioning and three hierarchical cluster analysis algorithms

Neural Network models are commonly used for cluster analysis in engineering, computational neuroscience, and the biological sciences, although they are rarely used in the social sciences. In this study we compare the classification capabilities of the 1-dimensional Kohonen neural network with two partitioning (Hartigan and Späthk-means) and three hierarchical (Ward's, complete linkage, and average linkage) cluster methods in 2,580 data sets with known cluster structure. Overall, the performance of the Kohonen networks was similar to, or better than, the performance of the other methods.     

The importance of Hinayāna and Mahāyāna

Volume 1. Hinayāna. Den tidlige indiske buddhisme. Volume 2. Mahāyāna. Den senere indiske buddhisme. Christian Lindtner, 1998, Copenhagen, Spektrum/Forum Publishers, Vol. 1: 228 pp., ISBN 87 7763 170 6; Vol. 2: 256 pp., ISBN 87 7763 174 9     

Schizotypy, taxometrics, and disconfirming theories in soft science: Comment on

Among the most consistently replicated findings in literature addressing the latent structure of psychopathology is evidence for a discrete latent class of individuals who are vulnerable to schizophrenia (schizotypes). Rawlings, Williams, Haslam, and Claridge (2008) challenge these findings by subjecting schizotypy scale scores to taxometric analysis, using a data simulation technique to accommodate variable skew. The authors conclude that schizotypy reflects a latent dimension, and that evidence for discrete latent structure from previous studies is likely an artifact of skewed variables. In this comment, we discuss (a) the philosophical implications of disconfirming well replicated findings in soft science with a single study, (b) important considerations when defining the schizotypy construct, (c) intricacies in executing and interpreting a taxometric analysis, and (d) problems with drawing strong conclusions from null results. Considerable evidence suggests that schizotypy is a discrete latent class, a conclusion that is unlikely the result of skewed variables.     

A repetition-suppression account of between-trial effects in a modified Stroop paradigm

Theories that postulate cognitive inhibition are very common in psychology and cognitive neuroscience [e.g., Hasher, L., Lustig, C., & Zacks, R. T. (2007). Inhibitory mechanisms and the control of attention. In A. Conway, C. Jarrold, M. Kane, A. Miyake, A. Towse, & J. Towse (Eds.), Variation in working memory (pp. 227-249). New York, NY: Oxford, University Press], although they have recently been severely criticized [e.g., MacLeod, C. M., Dodd, M. D., Sheard, E. D., Wilson, D. E., & Bibi, U. (2003). In opposition to inhibition. In H. Ross (Ed.), The psychology of learning and motivation (Vol. 43, pp. 163-214). Elsevier Science]. This paper poses and attempts to answer the question whether a research program with cognitive inhibition as its main theoretical assumption is still worth pursuing. We present a set of empirical data from a modified Stroop paradigm that replicates previously reported findings. These findings refer to between-trial effects previously described in the literature on Stroop, negative priming, and inhibition-of-return. Existing theoretical accounts fail to explain all these effects in an integrated way. A repetition-suppression mechanism is proposed in order to account for these data. This mechanism is instantiated as a computational cognitive model. The theoretical implications of this model are discussed.     

Grammatical and Phonological Influences on Word Order

ABSTRACT— During the grammatical encoding of spoken multiword utterances, various kinds of information must be used to determine the order of words. For example, whereas in adjective-noun utterances like "red car," word order can be determined on the basis of the word's grammatical class information, in noun-noun utterances like "… by car, bus, or …," word order cannot be determined on the basis of a word's grammatical class information. We investigated whether a word's phonological properties play a role in grammatical encoding. In four experiments, participants produced multiword utterances in which the words' onset phonology was manipulated. Phonological-onset relatedness yielded inhibitory effects in noun-noun utterances, no effects in noun-adjective utterances, and facilitatory effects in adjective-noun, noun-verb, and adjective-adjective-noun utterances. These results cannot be explained by differences in the stimulus displays used to elicit the utterances and suggest that grammatical encoding is sensitive to the phonological properties of words.     

Recognition of affective prosody in brain-damaged patients and healthy controls: A neurophysiological study using EEG and whole-head MEG

A passive oddball experiment was used in which stimuli were emotional exclamations differing in their affective tone. In both electroencephalography (EEG) and magnetoencephalography (MEG), deviants elicited an N300 component, sometimes accompanied by a slow wave. Both components had a symmetrical distribution, but the former was more posterior than the latter. The same responses to prosodic stimuli were significant in 6 of 27 patients with severe disorders of consciousness (persistent vegetative state and minimally conscious state) and in all 3 of the examined locked-in patients, indicating that the procedure can be applied for testing neurological patients. The occurrence of significant responses depended on the presence or absence of a lesion to the right temporal lobe. Obviously, the N300 depends on the activity of the right temporal cortex but does not originate there. We suggest that the component is related not to the recognition of affective prosody as such, but to the following detection of affective mismatch due to violations of emotional context of stimulation.