INCREASING THE INDEPENDENT RESPONDING OF AUTISTIC CHILDREN WITH UNPREDICTABLE SUPERVISION

We investigated the role of predictable versus unpredictable supervision on the independent task responding of three autistic children. In a predictable supervision condition, the therapist was present in the setting for a regular period of time and then was absent for the remainder of the session. In an unpredictable supervision condition, the therapist's presence was scheduled on a random, intermittent, and unpredictable basis throughout the session. The multiple baseline analysis showed that the unpredictable supervision produced much higher levels of on-task responding during the therapist's absence for all three children. Analysis of work completed during the therapist's absence also favored the unpredictable supervision condition. The results are discussed in relation to the literature on generalization and educational practice.     

Automatic and strategic effects in semantic priming: An examination of Becker’s verification model

Becker’s (1980) verification model, in conjunction with a two-strategy hypothesis, is cited as an alternative to a dual-process model (e.g., Posner & Snyder, 1975) of word recognition and semantic priming. Becket’s approach suggests that individuals can use either an “expectancy” or a “prediction” strategy in word recognition, and maintains that the verification model successfully predicts certain patterns of facilitation and inhibition in a semantic priming task that a dual-process model cannot. The present study demonstrated that when a long stimulus-onset asynchrony (SOA = 1,000 msec) is used between prime and target, support is given to Becker’s findings, and to the verification model approach. However, at a short SOA (200 msec), no evidence is found for the hypothesized difference between strategic processes. The results are consistent with other findings (e.g., Neely, 1977) in showing that strategic factors in semantic priming are largely inoperative at short prime-target SOAs, and suggests that Becker’s model is not general enough to rule out some type of dual-process model.     

Instrumental and expressive socialization: A false dichotomy

Barry, Bacon, and Child's (1957) cross-cultural study of sex differences in childhood socialization has been influential in bolstering the instrumental—expressive sex-role dichotomy. We critique their method of data analysis and factor analyze their data. Expressive and instrumental socialization are found to be separate factors or dimensions, rather than opposite ends of a single dichotomy. Additionally, no factor representing sex differences in socialization emerges, but rather each factor tends to contain substantively similar emphases in the training of both boys and girls.     

Micromanaging time: Measuring and controlling timing errors in computer-controlled experiments

Computer-controlled experiments present a number of potential sources of error in timing the presentation of events, including video refresh rate, keyboard scanning rate, and disk I/O times. A terminate-and-stay-resident routine implementing multiple millisecond-accuracy timers is presented. Interfaces permitting use of the timer with several higher level languages (C, FORTRAN , Pascal, and QuickBASIC) are described, as is a design for a two- to four-button response system using the computer’s printer port. A general strategy is described for using multiple timers to control and measure variation in critical experimental events. A C language program is provided to benchmark variation in the time required to perform common experimental tasks (screen refreshing, switching video pages, disk I/O, loop calculations), and results are summarized for several representative computers that use the IBM design.     

The Analytic Truth and Falsity of Disjunctions

Disjunctive inferences are difficult. According to the theory of mental models, it is because of the alternative possibilities to which disjunctions refer. Three experiments corroborated further predictions of the mental model theory. Participants judged that disjunctions, such as Either this year is a leap year or it is a common year are true. Given a disjunction such as Either A or B, they tended to evaluate the four cases in its ‘partition’: A and B, A and not‐B, not‐A and B, not‐A and not‐B, as ‘possible’ or ‘impossible’ in ways that bore out the difference between inclusive disjunctions (‘or both’) and exclusive disjunctions (‘but not both’). Knowledge usually concerns what is true, and so when participants judge that a disjunction is false, or contingent, and evaluate the cases in its partition, they depend on inferences that yield predictable errors. They tended to judge that disjunctions, such as follows: Either the food is cold or else it is tepid, but not both, are true, though in fact they could be false. They tended to infer ‘mirror‐image’ evaluations that yield the same possibilities for false disjunctions as those for true disjunctions. The article considers the implications of these results for alternative theories based on classical logic or on the probability calculus.     

Positive and negative patterning in human causal learning

Investigations of patterning discriminations by nonhuman animals have generally found that positive patterning is easier to learn than negative patterning. Studies of patterning discriminations in human causal learning tasks have failed to document any differences between positive and negative patterning. In the present study, human participants predicted an outcome on trials involving either a compound cue or its elements. Positive and negative patterning problems were successfully solved in a within-subjects design; negative patterning problems proved to be more difficult when an additional, 50% contingent cue was included (Experiment 2), but not when it was excluded (Experiment 1). Possible reasons for these results are discussed. The discussion concludes with an analysis of exemplar models (e.g., Pearce, 1994) of human causal learning and considers the conditions under which these models do and do not anticipate our results.