The Representation of Knowledge in Minds and Machines

Human knowledge can be represented as a propositional network in which the meaning of a node is defined by its position in the network. That is, the relationship between a node and its neighbours determines how this node is used in language understanding and production, i.e., its meaning. The propositions that make up such a network are predicate-argument structures with time and location slots. Schemas, frames, and production rules can be expressed in the same formalism. Implications for this contextual view of meaning are discussed. Since the construction of such a propositional network depends on hand coding and is therefore impractical, an alternative automatic statistical procedure is explored that yields a high-dimensional semantic space. Vectors in this space correspond to nodes in the propositional network, in that the meaning of a vector in the Latent Semantic Analysis space is given by its neighbouring vectors in that space.     

Commentary on "Family dynamics and children in medical research.

Gordon and Bonkovsky describe a disturbing case of research involving minors in their article "Family Dynamics and Children in Medical Research." As presented in the case, there is little doubt that the assent obtained from the children was inadequate for the proposed research and that the institutional review board (IRB) failed to assess sufficiently the risk-benefit ratio of the research to the child-subjects.     

An investigation of relationships between teachers' ratings of behavior and children's personality traits

This study examined the relationships between teachers' ratings of children's behavior on the Behavior Problem Checklist and children's selfreported personality source traits on ageappropriate Personality Questionnaires. The sample consisted of 254 children from first through eighth grades and 13 teachers in a rural Maine elementary school. Analysis of the data revealed that teachers' ratings and children's self-reports in grades four through six agreed more frequently about problematic behavior than did children's self-reports and teachers self-ratings in grades one through three and seven and eight. In general, the study (1) supported the validity of teacher judgments made with the Behavior Problem Checklist, (2) demonstrated the ckitical need for more than one perspective when identifying and defining maladaptive behaviors potentially indicative of emotional disturbance, and (3) suggested the need to increase the accuracy of teachers' perceptions and evaluations of children's behavior.     

Attributional Modesty in Women

Three experiments were conducted to test a two-factor model of the determinants of attributional modesty in women. Women tended to make modest attributions for success when they were concerned about how others would evaluate them and when they were concerned about their own self-image. Specifically, the knowledge that one's attributions would be public and the anticipation of future performance on similar tasks led to modesty. Self-derogatory attributions for failure occurred when the subjects thought their attributions would be public.     

Reversal learning of object and positional discriminations by mink, ferrets and skunks

Mink, ferrets and skunks were tested on successive reversals of two-choice object or positional discriminations in a modified Wisconsin General Training Apparatus. All species showed considerable improvement in performance after considerable training and some subjects exhibited one-trial reversal learning. Mink and ferrets persistently made more errors when position cues were relevant than when object cues were relevant; the reverse was true of skunks.     

Depth adjacency in simultaneous contrast

The Gelb phenomenon, as an example of whiteness contrast, was investigated with three amounts of separation in depth between the test and induction disc. The cue of binocular disparity was used to vary the perceived depth between the discs. It was found that the magnitude of the contrast effect decreased with an increase in the perceived depth between the two discs. This change was regarded as an instance of the adjacency principle. The problem of whether the binocular disparity cue per se or perceived depth was the significant variable was discussed. The consequences of the results were considered with respect to the relation between whiteness constancy and whiteness contrast and the problem of neural localization of the contrast effect.     

THE ROLE OF RESPONSE DELAY IN IMPROVING THE DISCRIMINATION PERFORMANCE OF AUTISTIC CHILDREN

This study investigated the influence of a response delay requirement on the discrimination performance of autistic children. In the context of a multiple baseline design with subsequent repeated reversals, two conditions were compared: a no-response-delay condition, where the child was allowed to make the target response immediately after presentation of the discriminative stimulus versus a response-delay condition, where the target response was permitted three seconds following the discriminative stimulus when the therapist would signal the child to respond. The results showed that the response-delay condition produced higher levels of correct responding than the no-response-delay condition. In addition, teachers in the research setting rated the response-delay procedure to be a practical and effective teaching technique that could be implemented in a classroom setting. The results were discussed in relation to the literature on impulsivity, and were interpreted as indicating that the response-delay procedure provides a valuable technique for teaching autistic children.     

A solid-state device for eliminating electrical noise and biopotentials in electromyographic (EMG) recordings

A small, low-cost, integrated circuit device is described. This circuit reduces electrical noise, such as that produced from a poor electrode-skin interface and power-line interference (60 Hz). Advantages of this device, with regard to use in electrically noisy environments and with long cables, are discussed.