Basic-level category discriminations by 7- and 9-month-olds in an object examination task

This study examines 7- and 9-month-olds' ability to categorize cats as separate from dogs, and dogs as separate from cats in an object examination task. In Experiment 1, 7- and 9-month-olds (N = 30) familiarized with toy cat replicas were found to form a category of cat that included novel cats but excluded a dog and an eagle. In Experiment 2, 7- and 9-month-olds (N = 30) familiarized with toy dog replicas were found to form a category of dog that included a novel dogs and a novel cat but excluded an eagle. These results mirror those of 3- to 4-month-olds tested with visual preference methods and stand in contrast to previously reported object examination results. Analyses of the distribution of features in the exemplars used to familiarize infants suggest that, like the 3- to 4-month-olds, the 7- and 9-month-olds in these studies form categories within the task, and on the basis of feature distributions.     

Writing errors by normal subjects

Writing is a complex process requiring visual memory, attention, phonological and semantic operations, and motor performance. For that reason, it can easily be disturbed by interfering with attention, memory, by interfering subvocalization, and so on. With 16 female third-year students (23.4 +/- 0.8 yr.) from the University of Trieste, we investigated the production of errors in three experimental conditions (control, articulatory suppression, and tapping). In the articulatory suppression condition, the participants produced significantly more linguistic impairments (such as agrammatism, unrelated substitutions, sentence omissions, and semantically deviant sentences), which are similar to linguistic impairments found in aphasia. On the tapping condition there were more perseverations, deletions, and substitutions of both letters and words. These data suggest that writing is not an automatic skill. Only after many years of experience and practice of processing information (through cortical to subcortical channels) can writing be considered an automatic skill. Limited experimental conditions can disrupt the writing system of normal subjects, probably interfering with the cortical to subcortical loops, and link normality to pathology.     

Effects of the Novel Acetylcholinesterase InhibitorN-Octyl-1,2,3,4-tetrahydro-9-aminoacridine on Locomotor Activity and Avoidance Learning in Mice

The acetylcholinesterase reversible inhibitorN-octyl-1,2,3,4-tetrahydro-9-aminoacridine (THA-C8) is a new synthesized derivative of tacrine (THA) characterized by an alkyl chain in the molecular structure which ameliorates the penetrability of the compound into the central nervous system. THA-C8 (0.1–5 mg/kg) significantly reduced spontaneous locomotor activity in CD1 mice at a dose of 3 mg/kg. Moreover, THA-C8 (0.2–2 mg/kg) significantly improved shuttle-box avoidance acquisition at doses (0.25, 0.3, 1 mg/kg) not affecting locomotion and that are much lower than the doses reported to be effective for THA in animal models. From the data reported it seems that the new compound could be interesting for therapeutic purposes.     

Figure-background segregation and the formation of illusory figures

Three experiments were carried out to test the relationship between figure-background segregation and illusory contours. Illusory figures are believed to arise as byproducts of figure-background segregation. When, in a scene, part of what should be the background becomes an illusory figure, a mechanism of contour attribution favoring the area in which the illusory figure appears takes place. This mechanism is prevented from operating when the attribution of the contour is inhibited by the presence of "groupable" (connectable) contours. Spatial proximity is one of the factors affecting such grouping: the closer the connectable contours, the more likely is their grouping in a single unit and the less likely is the emergence of an illusory figure. Experimental results showed that the illusory effect was established when contours were prevented from being connected. This outcome is interpreted as evidence that a mechanism of contour attribution is effective in the formation of illusory figures.     

Paradigms in Measure Theoretic Learning and in Informant Learning

We investigate many paradigms of identifications for classes of languages (namely: consistent learning, EX learning, learning with finitely many errors, behaviorally correct learning, and behaviorally correct learning with finitely many errors) in a measure-theoretic context, and we relate such paradigms to their analogues in learning on informants. Roughly speaking, the results say that most paradigms in measure-theoretic learning wrt some classes of distributions (called canonical) are equivalent to the corresponding paradigms for identification on informants.     

An Operational Logic of Proofs with Positive and Negative Information

The logic of proofs was introduced by Artemov in order to analize the formalization of the concept of proof rather than the concept of provability. In this context, some operations on proofs play a very important role. In this paper, we investigate some very natural operations, paying attention not only to positive information, but also to negative information (i.e. information saying that something cannot be a proof). We give a formalization for a fragment of such a logic of proofs, and we prove that our fragment is complete and decidable.     

Evidence for multiple routes in learning to read

We describe a multiple-route model of reading development in which coarse-grained orthographic processing plays a key role in optimizing access to semantics via whole-word orthographic representations. This forms part of the direct orthographic route that gradually replaces phonological recoding during the initial phases of reading acquisition. The model predicts distinct developmental trajectories for pseudo-homophone and transposed-letter effects - two benchmark phenomena associated with phonological recoding and coarse-grained orthographic processing, respectively. Pseudo-homophone effects should decrease over the first years of reading acquisition, whereas transposed-letter effects should initially increase. These predictions were tested in a lexical decision task with 334 children in grades 1-5, and 29 skilled adult readers. In line with the predictions, we found that the pseudo-homophone effect diminished as reading level increased, whereas the transposed-letter effect first increased and then diminished.     

Sex differences in how erotic and painful stimuli impair inhibitory control

Witnessing emotional events such as arousal or pain may impair ongoing cognitive processes such as inhibitory control. We found that this may be true only half of the time. Erotic images and painful video clips were shown to men and women shortly before a stop signal task, which measures cognitive inhibitory control. These stimuli impaired inhibitory control only in men and not in women, suggesting that emotional stimuli may be processed with different weights depending on gender.