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Generalization in place learning and geometry knowledge in rats.

Rats were trained to search for a food reward hidden under sawdust in the center of a square-shaped enclosure designed to force orientation on the basis of the overall geometry of the environment. They were then tested in a number of enclosures differing in shape and in size (rectangular-, double-side square-, and equilateral triangle-shaped enclosures). Results showed that rats transferred their place-finding ability to the novel enclosures. Our results add evidence to the hypothesis that the evolutionary roots of spatial cognition entail a primitive encoding of geometric relationships, as already shown using other tasks in rats.

Animals↗
PubMed2004

A general framework for learning rules from data.

With the aim of getting understandable symbolic rules to explain a given phenomenon, we split the task of learning these rules from sensory data in two phases: a multilayer perceptron maps features into propositional variables and a set of subsequent layers operated by a PAC-like algorithm learns Boolean expressions on these variables. The special features of this procedure are that: i) the neural network is trained to produce a Boolean output having the principal task of discriminating between classes of inputs; ii) the symbolic part is directed to compute rules within a family that is not known a priori; iii) the welding point between the two learning systems is represented by a feedback based on a suitability evaluation of the computed rules. The procedure we propose is based on a computational learning paradigm set up recently in some papers in the fields of theoretical computer science, artificial intelligence and cognitive systems. The present article focuses on information management aspects of the procedure. We deal with the lack of prior information about the rules through learning strategies that affect both the meaning of the variables and the description length of the rules into which they combine. The paper uses the task of learning to formally discriminate among several emotional states as both a working example and a test bench for a comparison with previous symbolic and subsymbolic methods in the field.

Algorithms↗
PubMed2005

Evaluation of general behavior, memory, learning performance, and brain sexual differentiation in F1 offspring males of rats treated with flutamide during late gestation.

Flutamide is a drug with antiandrogen effects that are mediated through androgen receptors (ARs). In this study, flutamide was subcutaneously administered to female rats (3, 10 or 30 mg/kg/day) on gestation Days 16-21 to evaluate effects on memory and learning performance in F1 offspring. Brain sexual differentiation was also evaluated by measuring the volume of the sexual dimorphic nucleus of the preoptic area (SDN-POA) and analyzing levels of androgen receptor (AR) mRNA expression in the prostate, hypothalamus and hippocampus. In F1 offspring exposed in utero to flutamide, evaluation of motor activity, learning performance and spatial perception showed that flutamide tended to exert a dose-dependent increase on the motor activity in F1 males, but no significant differences were identified in the other measurements. Prominent changes in development of the SDN-POA were apparent in males after maturation. Doses of > or =3 mg/kg/day resulted in significantly decreased length and volume of the SDN-POA compared to controls. These differences tended to become more marked at higher doses. Volumes of the SDN-POA did not differ significantly between F1 males and females exposed to flutamide at 30 mg/kg/day. AR mRNA was assayed using the dot-blotting method in F1 animals. In flutamide dose groups, AR mRNA expression tended to be increased in the prostate gland and decreased in the hippocampus. These results might suggest that exposure to flutamide in utero might affect controlling AR expression on a hormonal signal transduction system mediated by testosterone. However, these changes were not clearly correlated to learning performance in male offspring other than motor activity.

Androgen Antagonists↗
PubMed1984

A new look at learning needs in general practice.

Over a period of 18 months, trainees in the West Midlands were given a multiple choice questionnaire at the start of the general practice year to assess their factual knowledge in 14 areas of medicine and were given the opportunity to take the same test six months later. Sixty-five trainees who completed the test twice are the basis of the study, and their results are compared with 99 trainers who completed the paper once. In the pre-training test, the trainees' scores were significantly lower than their trainers' in total and in most individual subjects. In the mid-training test, the trainees' knowledge of most subjects had improved significantly over the six months. These results indicate that the teaching and assessment of factual knowledge should not be dismissed as unimportant in general practice training.

Education, Medical, Graduate↗
PubMed2003

The emergence of abstract ideas: evidence from networks and babies.

What is abstraction? In our view, abstraction is generalization. Specifically, we propose that abstract concepts emerge as the natural product of associative learning and generalization by similarity. We support this proposal by presenting evidence for two ideas: first, that children's knowledge about how categories are organized and how words refer to them can be explained as learned generalizations over specific experiences of words referring to categories; and second, that the path of concepts from concrete to more abstract can be observed throughout development and that even in their more abstract form, concepts retain some of their original sensory basis. We illustrate these two facts by examining, in two kinds of learners--networks and young children--the development of three abstract ideas: (i) the idea of word; (ii) the idea of object; and (iii) the idea of substance.

Cognition↗
PubMed1987

The effects of emotional arousal and increased speaking rate on children's newly learned (r) productions.

Generalization of newly learned phones into spontaneous speech remains a serious problem for many children with articulation disorders. It has been suggested that generalization may be governed, at least in part, by the stability of the new phone. Various clinicians have argued that response stability, in turn, may be affected by emotion and speaking rate. The present study was designed to determine whether children's newly learned (r) phones would be adversely affected by unpleasant emotions and/or faster than normal speaking rates. Sixteen misarticulating children retold a story after frustration and no frustration procedures, in combination with slow and fast slide presentations. In contrast to previous clinical assumptions, no significant differences in subjects' (r) productions were found among the conditions. The research implications and limitations, and suggestions for future research, are discussed.

Acoustic Stimulation↗