The generalization of deferred imitation in enculturated chimpanzees (Pan troglodytes)

Deferred imitation of object-related actions and generalization of imitation to similar but not identical tasks was assessed in three human-reared (enculturated) chimpanzees, ranging in age from 5 to 9 years. Each ape displayed high levels of deferred imitation and only slightly lower levels of generalization of imitation. The youngest two chimpanzees were more apt to generalize the model's actions when they had displayed portions of the target behaviors at baseline, consistent with the idea that learning is more likely to occur when working within the "zone of proximal development." We argue that generalization of imitation is the best evidence to date of imitative learning in chimpanzees. Electronic Publication     

Investigation into Combinatory Systems with Dual Combinators

Combinatory logic is known to be related to substructural logics. Algebraic considerations of the latter, in particular, algebraic considerations of two distinct implications (, ), led to the introduction of dual combinators in Dunn & Meyer 1997. Dual combinators are "mirror images" of the usual combinators and as such do not constitute an interesting subject of investigation by themselves. However, when combined with the usual combinators (e.g., in order to recover associativity in a sequent calculus), the whole system exhibits new features. A dual combinatory system with weak equality typically lacks the Church-Rosser property, and in general it is inconsistent. In many subsystems terms "unexpectedly" turn out to be weakly equivalent. The paper is a preliminary attempt to investigate some of these issues, as well as, briefly compare function application in symmetric -calculus (cf. Barbanera & Berardi 1996) and dual combinatory logic.     

Agreement Checking in Comprehension: Evidence from Relative Clauses

Work on agreement processing in comprehension in English has provided evidence that the plural feature is specified or marked and that the syntactic structure of the subject plays a role in checking features. It is argued here that the structure intervening between the subject and verb also plays a role in checking and that there is pressure to check features immediately. A self-paced reading study tested this proposal in a previously unstudied configuration: agreement between the verb in a subject relative clause (RC) and the relative clause head (e.g., the niece of the actors who was/were¨). According to the Construal Hypothesis (Frazier and Clifton, 1995), the structural relation between the RC and head is not immediately fully specified (unlike, for example, the relation between the subject and verb of a main clause). Thus, at the point when an agreeing verb is processed, the structure underlying the check may not yet be fully specified. This assumption about structural processing, together with the proposal for agreement checking in comprehension predicts (1) that there will be a large asymmetry between the processing of singular and plural agreeing verbs in the RC (larger than those seen in direct subject-verb predication) and (2) that there could be a role for agreement in determining RC attachment. Clear evidence for the first prediction was found; evidence for the second was inconclusive.     

Morphological priming: Dissociation of phonological, semantic, and morphological factors

Previous experiments based on a masked-priming paradigm revealed robust morphological priming effects induced by two derivational morphemes in Hebrew: the root and the verbal pattern. However, considering the special characteristics of the masked-priming paradigm, the possible contributions of phonological and/or semantic factors to these morphological effects could not be firmly assessed. In the present study, the role of these factors in morphological priming was examined, using cross-modal presentation. Experiment 1 revealed that priming between morphologically related words in Hebrew is determined by higher level linguistic characteristics and cannot be reduced to phonological overlap. Experiment 2 confirmed that morphological priming occurs in Hebrew even when primes and targets are not semantically related but, nevertheless, increases with semantic similarity. The results support the claim that morphological priming cannot be accounted for by considering semantic and phonological factors alone, and they exemplify the potential of using both masked and cross-modal priming to examine morphological processing.     

Attention and joint attention in preschool children with autism

Three experiments examined the role of attention in explaining dyadic (child-adult) and triadic (child-adult-object) joint attention difficulties in autism. Experiments 1 and 2 investigated children's ability to orient to an adult's attention bid and to follow the direction of a human or nonhuman cue. Experiment 3 tested ability to disengage and shift attention to objects. Results showed autism-specific difficulties at both dyadic and triadic levels. Children with autism were less responsive than developmentally delayed controls in orienting to attention bids and in following a human head-turn cue yet had no difficulty in shifting attention and were faster overall in orienting to targets. Results suggest a specific developmental delay in which children with autism rely on the presence of objects in the visual field to guide action. The relation between this problem and autistic children's difficulties with human communicative signals is discussed.     

The role of morphological constituents in reading Finnish compound words

The processing of transparent Finnish compound words was investigated in 2 experiments in which eye movements were recorded while sentences were read silently. The frequency of the second constituent had a large influence (95 ms) on gaze duration on the target words, but its influence was relatively late in processing: A clear effect only occurred on the probability of a third fixation. The frequency of the whole compound word had a similar influence on gaze duration (82 ms) and influenced eye movements at least as rapidly as did the frequency of the second constituent. These results, together with an earlier finding that the frequency of the first constituent affected the first fixation duration, indicate that the identification of these compound words involves parallel processing of both morphological constituents and whole-word representations.     

Development of object permanence in food-storing magpies (Pica pica)

The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no "A-not-B error" occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous.     

Analityczne komponenty definicji arbitralnych

Tre: Wstp. I. Definicje arbitralne. II. Syntetyczne konsekwencje definicji arbitralnych III. Analityczne i rzeczowe komponenty definicji arbitralnych. IV. Zdania analityczne.Artyku ten w nieznacznym tylko stopniu róni si od pracy doktorskiej, któr przedstawiem w 1962 r. Jak najuprzejmiej dzikuj Prof. Dr M. Kokoszyskiej-Lutman, Prof. Dr J. Supeckiemu oraz Doc. Dr M. Przeckiemu za szereg uwag i wskazówek, z których tak wiele skorzystaem przygotowujc ostateczn redakcj pracy.     

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