A critical comparison of two random-walk models for two-choice reaction time

Two random-walk models for two-choice reaction time, being the sequential probability ratio test model initially suggested by Stone and the relative judgment theory recently proposed by Link, are here compared. The comparison shows the precise mathematical relation between the models, the predictions they have in common, and two points at which they differ. Three experiments concerned with the effect of stimulus probability on two-choice reaction time are examined with respect to three predictions from the models. In this three-way comparison the two models are more like each other than either is to the data; a greater variety of phenomena is revealed than either model can at present accommodate.     

Behavioral treatment of obsessive-compulsive neurosis

Three chronic and severe obsessive-compulsive neurotics were treated with behavioral intervention strategies and psychotropic medication. The effects of treatment were evaluated in three separate experiments with single case experimental designs. The results suggest that response prevention was effective in reducing ritualistic behavior while the effects of flooding and antidepressant medication added little to outcome. The results also suggest that strategies aimed only at reducing compulsive behavior per se are insufficient in eliminating other associated difficulties (e.g., depressive symptoms, interpersonal problems) and that a comprehensive approach to treatment is needed.     

Required relaxation: a method of inhibiting agitative-disruptive behavior of retardates

Institutionalized retardates frequently exhibit agitative-disruptive behavior. Recent experiments have shown that overcorrective training in specific types of behavior can inhibit inappropriate behavior. A procedure was developed in which overcorrective practice in relaxation was given to each of eight adult retardates for their disruptions. The agitated resident was required to spend a fixed period of time in relaxation in his own bed upon each occurrence of agitation. This overcorrective relaxation resulted in a rapid, enduring and almost complete reduction in such behavior as self-injury, threats, physical aggression, screaming, crying, cursing and tantrums. Ward attendants strongly preferred the required relaxation procedure to the time-out technique and other inhibition procedures they had used. The procedure appears to be about as effective as alternative techniques and to have the advantages of ease of implementation and acceptability by ward staff and retardates as a ‘reasonable’ reaction to agitation.     

The cognitive basis of the comprehension and production of relational terminology

The comprehension of big, little, and same number and the productio of relational terminology was assessed in 168 preschool children. Stimuli were used which varied the relationships of length, number, and density. Language comprehension and production were related to the complexity of cognitive operations required by the task. Specifically, comprehension was easier in the situations in which length and number were positively correlated than when length provided no cue to number. Comprehension was most difficult when length and number were negatively correlated. There was asymmetry in language comprehension such that the positive term big, was comprehended earlier than little in some tasks; there was also asymmetry in production in that the child was more likely to use language related to the positive pole than to the negative pole. These data were interpreted as providing support for theories of the cognitive basis of language acquisition.     

Task parameters affecting the efficacy of a visual imagery learning strategy in younger and older children

Second- and sixth-grade children were presented a list of paired associates (concrete nouns) either at a faster (6-second) or a slower (12-second) presentation rate, under either an instruction to generate an interactive image for the pairs or a no strategy, control instruction. The list was composed of two pair types: easy-to-imaginally relate and difficult-to-imaginally relate pairs, as determined from a prior norming study. At the faster presentation rate, 2nd graders were able to benefit from the imagery strategy with easy pairs, but not with difficult pairs. At the slower rate, however, they applied the imagery strategy equally well to both pair types. Older children benefited from the imagery strategy with both pair types at both rates.     

Origin of the speech apparatus and its reconstruction in fossils.

Renewed enthusiasm has produced provocative speculations in recent literature on the origin of speech. The purpose of the present investigation is to expose the adaptive renovations underlying the emergence of a “Vocal Tract” and from this to define its anatomical substrate which governs the biomechanics of speech production. The vocal tract is a double resonator tube coupled in series and composed of oral and pharyngeal cavities. Analysis is made of the crucial structural elements of this complex from detailed dissections in modern man and the study of modern and fossil hominid crania. The study focuses on relations of the skull base, jaw, hyoid bone and the contained tongue, pharynx and valvular devices, calling into question recent reconstructions built on classical Neanderthal skulls.     

Cognitive structures in comprehension and memory of narrative discourse

The effects of structure and content variables on memory and comprehension of prose passages were studied in two experiments. The experimental passages exemplify a class of simple narrative stories that is described by a generative grammar of plot structures. A comprehension model is proposed that assumes a hierarchical organizational framework of stories in memory, determined by the grammar, representing the abstract structural components of the plot. The quality and characteristics of subjects' memory for stories were tested on a variety of experimental tasks in which story organization was manipulated. Comprehensibility and recall were found to be a function of the amount of inherent plot structure in the story, independent of passage content. Recall probability of individual facts from passages depended on the structural centrality of the facts: Subjects tended to recall facts corresponding to high-level organizational story elements rather than lower-level details. In addition, story summarizations from memory tended to emphasize general structural characteristics rather than specific content. For successively presented stories, both structure and content manipulations influenced recall. Furthermore, repeating story structure across two passages produced facilitation in recall of the second passage, while repeating story content produced proactive interference. The implications for a model of memory for narrative discourse are discussed.     

Closed- and open-class lexical access in agrammatic and fluent aphasics

Bradley, Garrett, and Zurif (Bradley, Computational distinctions of vocabulary type. Unpublished doctoral dissertation, MIT Press; Cambridge, MA, 1978; Biological studies of mental processes, MIT Press, Cambridge, MA, 1980) have suggested that closed-class word access is normally mediated by a different route than the open-class one, and that the loss of this closed-class route might account for agrammatism. However, in an earlier study ( Gordon & Caramazza, Brain and Language, 15, 143–160, 1982) we were not able to confirm a meaningful difference between closed- and open-class word frequency responsiveness of the type Bradley (unpublished dissertation, 1978) had seemed to find in normal subjects. We have now done a direct comparison of closed-class frequency sensitivity in agrammatic and nonagrammatic aphasics, to directly test Bradley and colleagues' hypotheses and to avoid some of the experimental problems with between-class frequency comparisons. We find that closed-class words behave similarly whether or not the subject is agrammatic. Therefore, the differences between agrammatic and nonagrammatic aphasics must arise at a deeper level (or levels) of lexical processing than the one probed by the frequency sensitivity effect.