Time-shrinking: the process of unilateral temporal assimilation

Our previous research on auditory time perception showed that the duration of empty time intervals shorter than about 250 ms can be underestimated hugely if they are immediately preceded by shorter time intervals. We named this illusion 'time-shrinking' (TS). This study comprises four experiments in which the preceding interval, t1, was followed by a standard interval, t2. When t1 < or = 200 ms, and t1 < or = t2, the underestimation of t2 came into view clearly. The absolute difference between t2 and t1 was the crucial factor for the illusion to appear. The underestimation increased when t2 increased from t1 to t1 + 65 ms, stayed at about 45 ms when t2 was between t1 + 65 ms and t1 + 95 ms, and disappeared suddenly when t2 exceeded t1 + 95 ms. This pattern of results was observed across all values of t1 < or = 200 ms. A model was fit to the data to elucidate the underlying process of the illusion. The model states that the perceived duration difference between t1 and t2 is reduced by cutting mental processing time for t2; in other words, that t2 assimilates to t1.     

Does action make the link between number and space representation? Visuo-manual adaptation improves number bisection in unilateral neglect

If the visual world is artificially shifted by only 10 degrees, people initially experience difficulty in directing their actions toward visual goals, but then rapidly compensate the visual distortion. The consequence of such adaptation can be measured as visual and proprioceptive aftereffects, as well as by performance on pointing tasks without visual feedback. Recent work has shown that more cognitive deficits can be improved following prism adaptation in patients with unilateral neglect. Here we show that a short visuo-manual adaptation to prisms improves performance on a mental number-bisection task recently shown to be impaired in unilateral neglect. The association previously found between space and number representation (the mental number line) may thus be grounded in common action principles. Our results suggest that visuo-motor plasticity functionally links parietal areas involved in space and number representation.     

Examining genetic and environmental effects on reactive versus proactive aggression

This study compared the contribution of genes and environment to teacher-rated reactive and proactive aggression in 6-year-old twin pairs (172 pairs: 55 monozygotic girls, 48 monozygotic boys, 33 dizygotic girls, 36 dizygotic boys). Genetic effects accounted for 39% of the variance of reactive aggression and for 41% of the variance of proactive aggression. The remainder of the variance was explained by unique environmental effects. Genetic as well as unique environmental effects were significantly correlated across reactive and proactive aggression (genetic correlation = .87, environmental correlation = .34), but this overlap was largely due to a common underlying form of aggression (i.e., teacher-rated physical aggression). Once common etiological factors due to physical aggression were accounted for, reactive and proactive aggression shared no other genes and only a few environmental influences, although additional specific genetic and environmental effects were observed for both reactive and proactive aggression. These specific effects indicate that both reactive and proactive aggression may be influenced mostly by socialization experiences that are specific to each type of aggression and only to a very small degree by specific genes.     

Do Early Difficult Temperament and Harsh Parenting Differentially Predict Reactive and Proactive Aggression?

The goal of this study was to examine the links between difficult temperament (i.e., negative emotionality) and harsh parental discipline during toddlerhood, and reactive and proactive aggression in kindergarten. These links were assessed on a longitudinal population-based study of 1516 boys and girls followed longitudinally from the age of 17 months through the age of 72 months. Two possible models were tested to examine the interplay between negative emotionality and harsh parenting in predicting later reactive aggression compared to proactive aggression. The first was an additive model where both aspects make unique contributions in predicting later reactive aggression. The second model was an interactive model where harsh parenting exacerbates the link between negative emotionality and reactive aggression. Results showed a specific contribution of negative emotionality to reactive aggression. The results relative to harsh parenting are more mixed but nonetheless in line with developmental models stressing different pathways to reactive and proactive aggression.     

Theoretical structure of adolescent alienation: a multigroup confirmatory factor analysis

This study examined the construct validity of adolescent alienation using second-order confirmatory factor analysis of the five dimensions conceptualized by Seeman (1959). Analysis was based on data from 275 high school students aged 14 to 18. The hypothesized multidimensionality of the construct was confirmed for both boys and girls using a second-order factor labeled alienation. Central dimensions of alienation as a latent construct were self-estrangement and powerlessness. Social isolation, meaninglessness, and especially normlessness were poorly explained by the second-order factor, suggesting that these dimensions entail enough specificity to be considered separately. A different theoretical model relating these dimensions is suggested and discussed.     

The bilingual Loch Ness Monster raises its non-asymmetric head again-or, why bother with such cumbersome notions as validity and reliability? Comments on Evans et al. (2000)

All of the experimental studies of the past 25 years combined and the meta-analyses of their findings have not advanced our knowledge of the lateralization of language in bilingual speakers one bit. We are left with a clutter of inherently uninterpretable contradictory results. Successive studies do not contribute a single brick to the edifice or a single piece to the puzzle-only more confusion. study is no exception. So far, there has been no demonstration of the validity of any experimental paradigm claiming to measure degree of language laterality in bilingual speakers. Experimentation is pointless unless the nature of what is alleged to be lateralized is clearly defined and the validity of the measures employed has been established. Because of the lack of validity of the paradigms used in bilingual laterality studies, experiments and meta-analyses of their findings cannot have any scientific significance. Like their predecessors, Evans et al. pay lip service to a number of methodological problems, but ignore their implications and simply carry on anyway. The authors ought to demonstrate, rather than assume, that degree of visual half-field advantage for single words corresponds to degree of lateralization of any component of language (even if only of words).     

Rewiring the dyslexic brain

Overcoming learning disorders is now becoming a realistic goal for neuroscientists and therapists. Seven years after their twin papers in Science suggesting the efficacy of intensive auditory training in children with language learning impairment, the Tallal-Merzenich team now report convincing evidence of just what such training programs can change in these children's brain. With the help of functional imaging, they demonstrate significant reorganization in both hemispheres after only eight weeks of daily training.     

Alzheimer's disease disrupts arithmetic fact retrieval processes but not arithmetic strategy selection

Three groups of healthy younger adults, healthy older adults, and probable AD patients, performed an addition/number comparison task. They compared 128 couples of additions and numbers (e.g., 4 + 9 15) and had to identify the largest item for each problem by pressing one of two buttons located under each item. Manipulations of problem characteristics (i.e., problem difficulty and splits between correct sums and proposed numbers) enabled us to examine strategy selection and specific arithmetic fact retrieval processes. Results showed that arithmetic facts retrieval processes, which were spared with aging, were impaired in AD patients. However, AD patients were able to switch between strategies across trials according to problem characteristics as well as healthy older adults, and less systematically than healthy younger adults. We discuss implications of these findings for further understanding AD-related differences in arithmetic in particular, and problem solving in general.     

Subject-Verb Agreement in Children and Adults: Serial or Hierarchical Processing?

Two processes, serial and hierarchical, are generally opposed to account for grammatical encoding in language production. In a developmental perspective, the question addressed here is whether the subject-verb agreement during writing is computed serially, once the words are linearly ordered in the sentence, or hierarchically, as soon as the number features are determined in a hierarchical frame. Adults and children from 3rd to 5th grades were requested to listen to sentences with built-in prepositional phrases or relative clauses and to transcribe them as quickly as possible. A serial hypothesis assumes that subject-verb agreement errors should be equally frequent with both preambles because each has the same length separating the subject head noun and the main verb. Conversely, according to a hierarchical view, errors should be more frequent with a prepositional phrase because the syntactic distance between the subject and the verb is greater than with a relative clause. The results revealed a main effect of the preamble manipulated in 5th graders and adults, but not in 3rd graders. These data were in favor of a hierarchical processing in older writers and a serial one in younger children. However, in 3rd grade, we assumed that the potential serial account was a result of the resource constraint on writing more than of a real serial processing of the agreement.     

An alternative perspective on von Winterfeldt et al.'s (1997) test of consequence monotonicity

D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (1997) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a bootstrap method. Their application offers new insights into consequence monotonicity as well as into von Winterfeldt et al.'s 3 experimental paradigms: judged certainty equivalents (JCE), QUICKINDIFF, and parameter estimation by sequential testing (PEST). For QUICKINDIFF, the authors found no indication of violations of "random consequence monotonicity." This sharply contrasts the findings of von Winterfeldt et al., who concluded that axiom violations were the most pronounced under that procedure. The authors found potential evidence for violations in JCE and certainty equivalents derived from PEST.