Effects of Stimulus Number and Target-to-Distractor Ratio on the Performance of Random Array Letter Cancellation Tasks

Cancellation tests are commonly used in the clinical assessment of visuospatial function, but there has been little study of task characteristics influencing performance. This study was designed to assess factors which affect cancellation performance. Sixteen healthy subjects sequentially performed four random-array letter cancellation tasks. The forms contained 50 and 100 stimuli and target:distractor (T/D) ratios of 1:4 and 1:9 with target letter “A” and randomly selected letter distractors. The primary performance measure was calculated as the number of correctly cancelled targets divided by the time to complete the task, corrected for accuracy. This measure revealed a strong effect of T/D ratio (p< .0001), with performance adversely affected by higher proportion of distractors. There was no effect of stimulus number. This suggests that T/D ratio should be considered in cancellation test design and interpretation.     

Therapeutic Contract Program: preliminary report on a behavioral alternative to the token economy

The token economy has been the primary model for the behavioral management of inpatient populations. However, this basically operant approach seldom emphasizes the development of cognitive-coping skills to help patients more effectively manage stressors that result in hospitalization. The Therapeutic Contract Program (TCP) is described as an inpatient-treatment strategy that is designed to help foster such cognitive-coping and self-control skills. While external structure is provided by components of this program, subprograms of the TCP have as their goal the development of internally-attributed coping skills and self-perceptions of competence. This preliminary report describes the structure of the TCP, as well as planned and in-progress measures of program participation and treatment outcome.     

The Interpretation of Anaphoric Noun Phrases Time Course, and Effects of Overspecificity

Two experiments investigated the interpretation of anaphoric noun phrases, and in particular those thatcould only be linked to their antecedents via knowledge-based inferences. The first experiment showed that much of the inferential processing was carried out as the anaphoric noun phrase was read, although there was some indication that inferential processing continued to the end of the clause. The second experiment attempted to establish why anaphoric noun phrases that are more specific than their antecedents cause problems. It showed that the difficulty did not lie in adding the extra information carried by the anaphor to the representation of the referent. Rather, we suggest, putting extra information in the anaphoric noun phrase disrupts the process of linking that noun phrase to its antecedent.