Is knowledge base development a necessary and sufficient condition for memory development?

The hypothesis that knowledge base development is an important condition for memory development was tested in two experiments. In Experiment 1 subjects from grades K, 6, and college participated in an incidental learning task where they analyzed words according to one of four featural systems: physical, acoustic, semantic, and imagery. Large developmental differences in recall were found in the imagery and semantic conditions, small differences were observed in the acoustic conditions, and no developmental differences were found in the physical condition. Experiment 2 involved presenting college students and third graders words either from categories highly salient to third graders, e.g., cartoons, games, etc., or from corresponding Battig and Montague categories generated by college students. Free recall and clustering performances showed significant interactions, with third graders superior on the third-grade salient items, and college students superior on Battig and Montague items.     

Effects of neutral and positive stimuli on stuttering: “Calling attention to stuttering” revisited

This study investigated the effects of presumably positive and neutral response-contingent stimuli on the occurence of stuttering. Eight adult stutterers spoke spontaneously during a 60-min experimental session, which was divided into three 20-min periods. During Condition I no stimuli were delivered. During Condition II a digital counter and a pair of yellow lights were activated each time the subject stuttered. During Condition III these same response-contingent stimuli were delivered, but with the additional factor that the subject would earn 5¢ each time the counter moved forward and the lights were illuminated. Conditions II and III were counterbalanced across subjects. The experimenter was unaware of which of the two contingencies were operative during Conditions II and III. Results showed no significant changes in occurence of stuttering due to either response-contingent stimulus. A discussion of theoretical and experimental implications is given.     

An individualistic approach to the evaluation and remediation of stuttering

A decision model is presented to facilitate the evaluation of stuttering behavior. This model calls for the evaluation to be conducted along a continuum with specified initiation and termination points. Following the evaluation, the information is formulated into an organized remediation procedure leading to fluent productions in the individual. This approach allows evaluation and remediation to be individualized to meet the needs and capabilities of each stutterer while allowing the professional the flexibility to choose remediation materials on the basis of objective information. Two case studies are presented to illustrate the use of the approach.     

Some effects of lick-contingent delays on the development of schedule-induced polydipsia

Experiments 1 and 2 examined the effects of various durations of lickcontingent delays of reinforcement on the development of schedule-induced polydipsia. Food was provided every 1 min in the absence of licking. Delays of 1 min or more effectively disrupted the development of the licking behavior. In Experiments 3 and 4 a lick-contingent stimulus was provided in addition to the delay of food delivery. A light, which was turned on by a lick and turned off by food, greatly enhanced the development of polydipsia under delays that had previously prevented such development. A tone proved less effective than the light in promoting the development of polydipsia. Adventitious reinforcement and conditioned punishment explanations of these results were considered. A distinction was drawn between the mechanism responsible for the development of schedule-induced behavior and that responsible for its maintenance.     

Assessment of the relative importance of S+ and S− in rats using differential training on intercurrent discriminations

The present studies assessed the degree of stimulus control exerted by S+ and S? without confoundings of stimulus novelty and stimulus ambiguity. In Experiment 1, rats were trained on two intercurrent simultaneous discrimination problems with nine times more training given on one than the other. Then the animals were given transfer tests with re-paired stimuli. The results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination. Experiment 2 provided a test of the possibility that the relative degree of control by S? varies with different amounts of training. Three groups were trained on two intercurrent simultaneous discrimination problems; each group was given 7, 11, or 15 times more training on one problem than the other. Then transfer tests were given with re-paired stimuli. Again the results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination.     

Developmental auditory agnosia in the severely retarded: A further investigation

The hypotheses were investigated that (a) ability to recognize the auditory perceptual stimuli for familiar events is a developmental correlate to language acquisition and (b) the low functioning mentally handicapped suffer from auditory agnosia and are impaired in this ability. The subjects were 42 nonretarded children of ages 3 through 6 and 53 severely and moderately retarded, noninstitutionalized students. The retarded subjects were matched by mental age to the chronological age of the nonretarded children. The stimuli were 49 environmental sounds; the task consisted of sound-and-picture matching-to-sample. Group membership and developmental age were the factors in an analysis of variance design. The results revealed a strong effect of developmental age (p <. 0001). The effect of group was not significant, indicating that auditory agnosia may not be common among the lower functioning retarded. The assumption that agnosia may be a major factor underlying the language disability of the severely retarded was reexamined. It was suggested that the severely retarded achieve the requisite perceptual-semantic knowledge base for language too late, after the critical age for spontaneous and efficient language learning has passed.     

Effects of sentential stress and word class upon comprehension in Broca's aphasics

The roles which word class (open/closed) and sentential stress play in the sentence comprehension processes of both agrammatic (Broca's) aphasics and normal listeners were examined with a word monitoring task. Overall, normal listeners responded more quickly to stressed than to unstressed items, but showed no effect of word class. Aphasics also responded more quickly to stressed than to unstressed materials, but, unlike the normals, responded faster to open than to closed class words regardless of their stress. The results are interpreted as support for the theory that Broca's aphasics lack the functional underlying open/closed class word distinction used in word recognition by normal listeners.     

Central deafness and subcortical motor aphasia

Clinical and autopsy studies were made on a right-handed man who had central deafness and subcortical motor aphasia, and the literature on central deafness and on subcortical motor aphasia was analyzed. Central deafness is due to bilateral destruction of the primary auditory cortex. It is sometimes difficult to distinguish from word deafness and from auditory agnosia, which are due to pathology in other parts of the temporal lobes. There is almost always some preserved hearing in central deafness, possibly from some auditory pathway other than the classical pathway. In this patient the subcortical motor aphasia was due to bilateral destruction of the motor cortex for the mouth and throat. In some other cases subcortical motor aphasia was due to the same pathology that usually causes Broca's aphasia; in these cases the unexpected preservation of writing was perhaps related to some difference in how language functions were organized in the brain.