FUNCTIONAL ANALYSIS AND TREATMENT OF CIGARETTE PICA

A series of analyses was conducted to assess and treat the pica of cigarette butts by a young man with mental retardation and autism. First, we demonstrated that pica was maintained in a condition with no social consequences when the available cigarettes contained nicotine but not when the cigarettes contained herbs without nicotine. Second, a choice assessment (Fisher et al., 1992) confirmed that tobacco was preferred over the other components of the cigarette (e.g., paper, filter, etc.). Third, an analogue functional analysis (Iwata, Dorsey, Slifer, Bauman, & Richman, 1982/1994) demonstrated that cigarette pica was maintained independent of social consequences. Fourth, a treatment designed to interrupt the hypothesized response—reinforcer relationship reduced consumption of cigarettes to zero. Finally, because cigarette pica occurred primarily when the individual was alone or under minimal supervision, a procedure based on stimulus control was developed to improve the effectiveness of the intervention in these situations.     

Development of consensus about child oppositional behavior: Increased convergence with entry into school

This study examines the relation between parent and teacher ratings of oppositional behaviors in children from kindergarten to second grade. One cross-sectional sample of 85 boys in kindergarten, first, and second grade was assessed for problem behavior on the basis of reports from the children, parents, teachers, and trained observers. The second sample consisted of parent and teacher ratings of both boys and girls in a longitudinal design at 5 and 7 years of age. Results from both studies indicate that agreement does increase around the time of the child's transition into school and that each informant influences the ratings of the others over time.     

Eye movements while reading and searching spatially transformed text: A developmental examination

The effects of spatial manipulation on eye movement when subjects either read or searched through paragraphs were examined. Adults, third, and fifth graders were presented with paragraphs which were typed normally or in alternating case (upper and lower). The spacing between the words was either normal, filled, or absent. The results show that approximately twice as many character spaces are processed during search as during reading. Subjects made more fixations of shorter duration during search than reading. The data indicated that the ability to vary the size of the perceptual unit develops with experience. When spatial cues were unavailable, all subjects resorted to a letter-by-letter-like processing strategy in reading but not in search. Although reading and search were found to be sensitive to the same types of spatial manipulations, discrepancies of span and speed suggest qualitative differences; comprehension demands during reading can account for these differences. The data were interpreted to provide support for the two-stage model of Hochberg (1970).     

On the locus of the divided-attention effects

Reaction times in a choice reaction task were used to localize the livided-attention effect (less proficient performance under dual than under ingle-taks conditions) in a sequential-stage model of human information processing. Experiment 1 eliminated a central (memory-dependent) processing tage, while Experiment 2 suggested that a stimulus sampling process within the hitial encoding stage was the locus of the effect. Thus, the effect was localized in the input, not the central or an output stage of processing. A slower stimulus ampling rate was indicated under dual-than under single-task conditions.     

Estimating hypothesis strengths

Violation of the exhaustiveness postulate of Levine’s (1965) hypothesis model is shown to produce large errors in the estimation of the proportions of problems mediated by the various hypotheses. In two cases, when stat-subject simulations satisfied the postulates, estimates were reasonably close to actual values. One interpretation proposes that negative values of estimates are an indication that the exhaustiveness assumption is violated. An alternative computational method is described.     

A possible artifact in serial response behaviour

Using 12 subjects who worked for 12 min on a self-paced 5-choice serial response task, it was hypothesised that external events inserted by computer program in accordance with a random sequence of time intervals would bisect a greater proportion of long response times, and thus that the parameters of the resulting distributing would be greater than the parameters of the parent distribution or of a distribution in which responses were selected at random. The results confirmed the hypothesis and it was concluded that the Waiting Time Paradox as described by Feller (1966), is applicable to situations involving serial response tasks.