Operant conditioning of eye movement in the monkey (Macaca nemestrina)

With the horizontal electrooculographic potential as the operant, four monkeys (Macaca nemestrina) were conditioned to move their eyes at high and low rates by initial use of fixed-ratio schedules of reinforcement, followed by a changeover to multiple schedules of fixed-ratio reinforcement and discriminated differential reinforcement of low rate. These differences in rate of eye movement were not observed in a control animal given the same patterns of discriminative stimuli and deliveries of the reinforcing agent independent of its eye movements.     

Spatial problem solving by rats: Exploration and cognitive maps

Two experiments were performed in an attempt to examine the contribution of the exploratory experience to performance on Maier's 3-table spatial problem-solving task. In the first experiment, the runway configurations were altered between exploration and testing. It was found that following an initial impairment animals exposed to the altered runway configurations could perform as well as animals not confronted with an altered runway configuration on the test trial. In the second experiment, animals were allowed to explore only elements of the problem space. Exploration of either the runways only or the tables only led to unsuccessful performance on the 3-table task. The results of both experiments were related to current theory of cognitive mapping.     

Microcomputers in schools: Impact on the social life of elementary classrooms

Microcomputers are becoming increasingly available to schools, but little research is available concerning the impact of this technology for children. Two studies were conducted to examine some possible social effects of the use of microcomputers in elementary school classrooms where children are learning to program in LOGO. First, the task-related interaction that children engaged in with each other was observed and recorded in two classrooms (8- to 9-year-old s, and 10- to 11-year-olds) as the children worked on both computer and non-computer tasks. The children in both classrooms were significantly more likely to collaborate with each other when they worked with the computers, when compared with their interaction over other classroom tasks. The second study examined children's perceptions of their peers as resources for help with a variety of classroom tasks. When compared with other work, the computer context was the one where children more consistently identified certain of their peers as resources for help.     

The reaction to frustration of middle- and lower-class children

Preschool age, white children from lower and middle socioeconomic backgrounds were exposed separately to the same operant analog of the Amsel “double alley” procedure. Two measures of responding, latency of press and pressing rate, were taken following frustration and reward of prior responding. The middle-class children responded slower, in both measures, on nonrewarded compared to rewarded trials, a reversal of the more frequently observed frustration effect (FE). The lower-class children, by contrast, showed the usual FE, shorter response latencies following frustrative nonreward. The FE was not observed with the rate measure. The obtained socioeconomic class difference in reaction to frustration was discussed in terms of the possible relationship to class differences in perceived locus of control of reinforcement. An alternative explanation relating the results to the maximizing vs response patterning behavior in three-choice probability learning tasks was also discussed.     

The selection of homograph meaning: Word association when context changes

In a study of lexical ambiguity processing, responses to homographs were examined in a word association task. The context of repeated exposures of a homograph was manipulated by requiring a response to a word related to a meaning of the homograph on the trial prior to homograph presentation. A change of that relationship reduced the effectiveness of the contextual item as a prime on the second occurrence of the homograph. In response to a third unprimed occurrence of the homograph, associations were consistent with a conclusion that when semantic contexts are opposed, a "primacy effect" is obtained. The overall effects in the studies reported are seen as consistent with the theoretical view of Simpson and Kang (1994) that processing and responding to one meaning of a homograph result in the inhibition of alternative meanings. A mechanism to account for that inhibition is proposed.     

Item-focussed Trees for the Identification of Items in Differential Item Functioning

A novel method for the identification of differential item functioning (DIF) by means of recursive partitioning techniques is proposed. We assume an extension of the Rasch model that allows for DIF being induced by an arbitrary number of covariates for each item. Recursive partitioning on the item level results in one tree for each item and leads to simultaneous selection of items and variables that induce DIF. For each item, it is possible to detect groups of subjects with different item difficulties, defined by combinations of characteristics that are not pre-specified. The way a DIF item is determined by covariates is visualized in a small tree and therefore easily accessible. An algorithm is proposed that is based on permutation tests. Various simulation studies, including the comparison with traditional approaches to identify items with DIF, show the applicability and the competitive performance of the method. Two applications illustrate the usefulness and the advantages of the new method.     

Minimax d-optimal designs for item response theory models

Various different item response theory (IRT) models can be used in educational and psychological measurement to analyze test data. One of the major drawbacks of these models is that efficient parameter estimation can only be achieved with very large data sets. Therefore, it is often worthwhile to search for designs of the test data that in some way will optimize the parameter estimates. The results from the statistical theory on optimal design can be applied for efficient estimation of the parameters.A major problem in finding an optimal design for IRT models is that the designs are only optimal for a given set of parameters, that is, they are locally optimal. Locally optimal designs can be constructed with a sequential design procedure. In this paper minimax designs are proposed for IRT models to overcome the problem of local optimality. Minimax designs are compared to sequentially constructed designs for the two parameter logistic model and the results show that minimax design can be nearly as efficient as sequentially constructed designs.