Psychophysiological Identification of Depression Subtypes in Older Adults: Problematic Diagnostic Heterogeneity in the DSM-III-R and DSM-IV

The DSM-IV does not subclassify patients with depression on the basis of anxiety level. Hence a significant confound may exist in all outcome studies that employ DSM definitions of depression. To establish that objectively identifiable anxious and nonanxious subtypes of depression do indeed exist, a psychophysiological assessment battery was used with 114 treatment-seeking older adults. Dichotomous criterion categorization as either Nonanxious Depressed or Anxious Depressed was based on (a) DSM-III-R/DSM-IV diagnosis, and (b) standardized questionnaires of psychopathology. Multivariate analyses revealed no differences between groups when DSM criteria were used to classify participants. However, identical analyses using phenomenological diagnostic criteria indicated that anxious and nonanxious depressed participants differed in their psychophysiological response to negative imagery. Although anxious and nonanxious depressed participants evince different psychophysiological response patterns, these differences unfortunately are obscured by the DSM. Consequently, a phenomenological classification system may be more appropriate with affective disorders.     

An item response model with internal restrictions on item difficulty

An IRT model based on the Rasch model is proposed for composite tasks, that is, tasks that are decomposed into subtasks of different kinds. There is one subtask for each component that is discerned in the composite tasks. A component is a generic kind of subtask of which the subtasks resulting from the decomposition are specific instantiations with respect to the particular composite tasks under study. The proposed model constrains the difficulties of the composite tasks to be linear combinations of the difficulties of the corresponding subtask items, which are estimated together with the weights used in the linear combinations, one weight for each kind of subtask. Although the model does not belong to the exponential family, its parameters can be estimated using conditional maximum likelihood estimation. The approach is demonstrated with an application to spelling tasks. We thank Eric Maris for his helpful comments.     

Program Constructions that are Safe for Bisimulation

It has been known since the seventies that the formulas of modal logic are invariant for bisimulations between possible worlds models — while conversely, all bisimulation-invariant first-order formulas are modally definable. In this paper, we extend this semantic style of analysis from modal formulas to dynamic program operations. We show that the usual regular operations are safe for bisimulation, in the sense that the transition relations of their values respect any given bisimulation for their arguments. Our main result is a complete syntactic characterization of all first-order definable program operations that are safe for bisimulation. This is a semantic functional completeness result for programming, which may be contrasted with the more usual analysis in terms of computational power. The 'Safety Theorem' can be modulated in several ways. We conclude with a list of variants, extensions, and further developments.     

Socialism in One Country: A Reassessment

Until 1917 Lenin and Trotsky believed that an isolated revolutionary Russia would have no chance of survival. However, from 1917 to 1923 Lenin's standpoint on this matter underwent a complete reversal. First he came to the conclusion that socialism could be built in an isolated Russia, although it would remain incomplete in the absence of the world revolution. By 1923 he was abandoning that latter qualification too. The standpoint of Stalin and Bukharin in the debate on socialism in one country of 1925–26 was more orthodox-Leninist than the position taken by Trotsky, who had at first also embraced the notion of incomplete socialism, but subsequently returned to the old concept, abandoned by Lenin, that the restoration of capitalism was inevitable in the absence of the world revolution.     

Interfering with the Central Executive by Means of a Random Interval Repetition Task

Four dual-task experiments are reported in which a short-term memory task is performed concurrently with a random interval repetition task, which was designed to interfere with functions normally attributed to the central executive in the working memory model of Baddeley and Hitch (1974). The task was found to interfere with supra-span serial recall and with backward memory span, but did not disrupt performance on a forward-memoryspan task. The effects were observed in dissociation with effects of articulatory suppression and matrix tapping, so that the locus of the effects of the new task is not due to the slave systems. In addition, single-task random-interval repetition performance was sampled and compared to performance in the dual-task conditions of all four experiments. Although quality of tapping performance differed between the single-task and the dual-task conditions, it was not related to recall performance. All the results are discussed with reference to the working memory model.     

Storage of verbal associations is sufficient to activate the left medial temporal lobe

Neuroimaging studies have shown that memory encoding activates the medial temporal lobe (MTL). Many believe that these activations are related to novelty but it remains unproven which is critical - novelty detection or the rich associative encoding it triggers. We examined MTL activation during verbal associative encoding using functional magnetic resonance imaging. First, associative encoding activated left posterior MTL more than single word encoding even though novelty detection was matched, indicating not only that associative encoding activates the MTL particularly strongly, but also that activation does not require novelty detection. Moreover, it remains to be convincingly shown that novelty detection alone does produce such activation. Second, repetitive associative encoding produced less MTL activation than initial associative encoding, indicating that priming of associative information reduces MTL activation. Third, re-encoding familiar associations in a well-established way had a minimal effect on both memory and MTL activation, indicating that MTL activation reflects storage of associations, not merely their initial representation.     

We almost had a great future behind us: The contribution of non-linear dynamics to developmental-science-in-the-making

Classical developmental theories, like those of Piaget, Werner and Vygotsky, were on the verge of developmental science, the study of phenomena from the point of view of development. Methodological and theoretical shifts in the 1960s changed the original goals and questions and turned developmental psychology into a discipline that is, on the whole, more like a subservient than a leading branch of psychology. Dynamic systems theory, which has its roots in mathematics and physics, can help developmental theory out of its current blind alley by providing the general theoretical frameworks and methods for bringing the dynamic aspects of change back to the fore. By doing so, it will help turn the scientific course back in the direction of developmental science.     

Parental loss of close family members and propensities towards absorption in offspring

Parental unresolved/disorganized responses to loss assessed in the Adult Attachment Interview predict infant disorganized (D) attachment. Parental experiences of loss near the birth of an infant should therefore increase the likelihood of D attachment to that parent. Liotti (1992) suggested that D attachment may increase tendencies to altered states of consciousness, and some support for this hypothesis has been obtained in clinical and high-risk samples. Here, Tellegen's Absorption Scale was used to measure propensities to altered consciousness in two low-risk samples of young adults (N=136, N=308). In both studies, participants whose parents experienced familial loss within two years of their birth showed elevated levels of absorption. These outcomes (a) support the proposed connection between disorganized attachment and tendencies to altered consciousness, and (b) suggest that queries regarding parental loss experiences should be further explored as a ‘rough and ready’ estimate of disorganized attachment in large-scale studies.     

Symmetry and selective attention: A dissociation between effortless perception and serial search

It is widely assumed that symmetry is an important visual primitive, probably encoded without the need for attention. Julesz’s (1981) definition ofeffortless perception, which states that any stimulus property perceived for exposure durations of 160 msec or less is detected preattentively, contributed greatly to this belief.Single pattern studies confirm that symmetry is detected within this limit. In the present study, however, Julesz’s operationalization is compared with themultiple pattern visual search task, to see whether symmetry as a wholistic property is detected in parallel. The results show that symmetry detection times are highly dependent on the number of distractor patterns. The findings are similar for dot patterns, wire polygons, solid block shapes, and simple parentheses. We conclude that symmetry detection per se requires selective attention, but that some related grouping or segmentation mechanism may operate preattentively.     

A solution to the effect of sample size on outlier elimination

Results from a Monte Carlo study demonstrate how a non-recursive, a simple recursive, a modified recursive, and a hybrid outlier elimination procedure are influenced by population skew and sample size. All the procedures are based on computing a mean and a standard deviation from a sample in order to determine whether an observation is an outlier. Miller (1991) showed that the estimated mean produced by the simple non-recursive procedure can be affected by sample size and that this effect can produce a bias in certain kinds of experiments. We extended this result to the other three procedures. We also create two new procedures in which the criterion used to identify outliers is adjusted as a function of sample size so as to produce results that are unaffected by sample size.