THE TRAINABILITY OF FORMAL THINKING: A CROSS-CULTURAL COMPARISON

In order to investigate what is learned in a training study on inductive reasoning, three tests were composed, involving two stimulus domains, namely letters and figures. Each test was composed on the basis of a set of explicitly defined item generating rules. The two figural tests were isomorphic tests, that is, they had identical problem structures but invoked different stimulus domains, simple geometric patterns and drawings of fruit. These tests were administered to pupils from grade 6 in The Netherlands, Surinam and Zambia. Half of each class was then trained at one of the three tests, while the other half did not get any training. During the training the pupils were taught to solve the items by trying to detect the features of the item generating rules. Four possible outcomes of transfer studies were postulated, differing in the generality of transfer of the results. By means of a Multivariate Analysis of Variance with Repeated Measures it was possible to differentiate between the four kinds of transfer; a pattern of fairly restricted transfer was demonstrated in each culture. Furthermore, in Zambia a remarkable score increase was found at the Letter Test, occurring both in the experimental and in the control condition. It was argued that this increase was caused by improved test-taking skills, learned at the first test administration.     

Postural determinants of frontal-position advantage in listening to speech

Previous work has shown that when a subject is seated with body, head, and eyes oriented in the same direction, speech coming from the front is better perceived than speech coming from other directions. The question asked was which segments of the body are critical in determining the advantage of the frontal position. It was found that the effect does not depend exclusively on the orientation of the head relative to the source, since the advantage is reduced not only when the head is deviated laterally towards a competing source, but also when the gaze or the trunk and the limbs are deviated in that direction. Frontal position advantage is thus not a purely acoustical or auditory phenomenon, but depends, at least partly, on interactions at deeper levels.     

Feature memory and binding in young and older adults

Intact memory for complex events requires not only memory for particular features (e.g., item, location, color, size), but also intact cognitive processes for binding the features together. Binding provides the memorial experience that certain features belong together. The experiments presented here were designed to explicate these as potentially separable sources of age-associated changes in complex memory—namely, to investigate the possibility that age-related changes in memory for complex events arise from deficits in (1) memory for the kinds of information that comprise complex memories, (2) the processes necessary for binding this information into complex memories, or (3) both of these components. Young and older adults were presented with colored items located within an array. Relative to young adults, older adults had a specific and disproportionate deficit in recognition memory for location, but not for item or for color. Also, older adults consistently demonstrated poorer recognition memory for bound information, especially when all features were acquired intentionally. These feature and binding deficits separately contribute to what have been described as older adults’ context and source memory impairments.     

Wajsberg algebras and post algebras

We give a presentation of Post algebras of ordern+1 (n1) asn+1 bounded Wajsberg algebras with an additional constant, and we show that a Wajsberg algebra admits a P-algebra reduct if and only if it isn+1 bounded.This autor is partially supported by Grant PB90-0465-C02-01 of D.G.I.C.Y.T. of SpainPresented byJan Zygmunt     

Visual search for global/local stimulus features in humans and baboons

Fagot and Deruelle (1997) demonstrated that, when tested with identical visual stimuli, baboons exhibit an advantage in processing local features, whereas humans show the “global precedence” effect initially reported by Navon (1977). In the present experiments, we investigated the cause of this species difference. Humans and baboons performed a visual search task in which the target differed from the distractors at either the global or the local level. Humans responded more quickly to global than to local targets, whereas baboons did the opposite (Experiment 1). Human response times (RTs) were independent of display size, for both local and global processing. Baboon RTs increased linearly with display size, more so for global than for local processing. The search slope for baboons disappeared for continuous targets (Experiment 2). That effect was not due to variations in stimulus luminance (Experiment 3). Finally, variations in stimulus density affected global search slopes in baboons but not in humans (Experiment 4). Overall, results suggest that perceptual grouping operations involved during the processing of hierarchical stimuli are attention demanding for baboons, but not for humans.     

Associative learning in baboons (Papio papio) and humans (Homo sapiens): species differences in learned attention to visual features

We examined attention shifting in baboons and humans during the learning of visual categories. Within a conditional matching-to-sample task, participants of the two species sequentially learned two two-feature categories which shared a common feature. Results showed that humans encoded both features of the initially learned category, but predominantly only the distinctive feature of the subsequently learned category. Although baboons initially encoded both features of the first category, they ultimately retained only the distinctive features of each category. Empirical data from the two species were analyzed with the 1996 ADIT connectionist model of Kruschke. ADIT fits the baboon data when the attentional shift rate is zero, and the human data when the attentional shift rate is not zero. These empirical and modeling results suggest species differences in learned attention to visual features. Received: 30 May 1998 / Accepted after revision: 13 September 1998     

Images of numbers, or "When 98 is upper left and 6 sky blue".

Some people declare that they possess a personal visual representation of numbers: some automatically "see" the numbers they are confronted with in a precise location in a structured mental space, others "associate" specific colours with given numbers. Such visuo-spatial representations of numbers were first described by Galton in 1880 but have since received little attention from psychologists. It is the aim of this article to describe these mental representations and discuss their role in number processing. The authors first review Galton's observations, and then present their own. Finally, they discuss the relevance of these visuo-spatial representations in relation to contemporary debates on number representation and calculation.     

Lateralization in haptic processing: An apparatus for analyzing manual strategies

We describe an apparatus for testing laterality in haptic processing in the discrimination of nonsense shapes in humans or monkeys. The system, which permits either mono- or dichhaptic discrimination, automatically provides data on the measurement of accuracy along with information on hand exploratory strategies.