Choice of extinction-signalling stimuli by rats

Rats in a two-lever situation were exposed to alternating periods of intermittent reinforcement and extinction. Extinction periods were either unsignalled or were signalled by a response-produced stimulus. The signal was sometimes a stimulus paired with food delivery in the reinforcement periods and sometimes a stimulus that occurred only in extinction periods. Both kinds of signal accelerated extinction relative to the unsignalled condition. When the signal was the stimulus paired with food in reinforcement periods, the rats tended to prefer the lever that gave that signal even though the signal accelerated extinction. There was no comparable effect for the stimulus that occurred only in extinction periods; when this signal was contingent on only one of the two levers, the rats either avoided it (Experiment 3) or were indifferent (Experiment 4). It is concluded that a stimulus can be a “secondary reinforcer” as measured by preference, even though it decreases resistance to extinction; the implications are discussed with reference to formal theories of choice behavior.     

Precocious conservation in context: The solution of quantity tasks by nonquantitative strategies

C. Sinha and B. Carabine's (1981, Journal of Child Language, 8, 109–129) claim of a U-shaped course to the development of quantitative knowledge with an early stage of conservation based on functional significance was tested in two experiments. Children at three age groups from 3 to 6 years were presented with the original procedure or control versions in which the display was slightly altered. Results showed that although Sinha and Carabine's result was replicable, their interpretation is unwarranted. Performance in the younger groups was best interpreted as the use of nonquantitative possession or position strategies.     

Autocorrelation of choice-reaction times.

A choice-reaction (CR) task requires that the subject estimate, raking the warning signal or his response on the preceding trial as a reference point, the time when the reaction stimulus is due, so that he can begin deciding on his response at an appropriate time. This paper presents a model for the reproduction of temporal intervals, with particular emphasis on the sequential statistics of a series of such reproductions. When this model is concatenated with the sequential probability ratio test model for 2CRT, it provides a quantitative account of the pattern of autocorrelation found in a series of RTs. There is no corresponding autocorrelation in the incidence of errors, however, because after an error the subject systematically adjusts the epoch at which he begins sampling as a precaution against a further error. These post-error adjustments can readily be incorporated into the model. The ideas presented enable several different CR phenomena to be related, and they have implications for the relation between speed and accuracy, for the form of empirical distributions of RTs, and for the effects of temporal uncertainty.     

Choice reaction performance following an error

Some data are presented showing the changes in choice-reaction time (CRT) and the probability of error (PE) on the five trials following an error in a two-choice experiment. The magnitudes of the increase in RT and the decrease in PE are different according as the error-trial stimulus is re-presented or the alternative stimulus is preservec. In addition, RT is quicker to recover its equilibrium value than is PE.This pattern of changes implicates two distinct adjustments to the underlying decision process following an error: (i) a selective outward adjustment of the boundary at which the error was uttered, and (ii) a delay, with respect to presentation of the reaction stimulus, of the epoch at which the subject begins sampling information from the stimulus display. When these ideas are concatenated with the sequential probability-ratio-test model for CRT, a theoretical relation can be derived between the difference in mean RT for an error and for the same response given correctly, on the one hand, and the decrease in PE on the trial following an error, given that the alternate stimulus is presented, on the other. This relation is satisfied by the data.     

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.     

Nest material and food as reinforcers for fixed-ratio responding in mice

Three experiments investigated the importance of operant-reinforcer distance as a factor affecting continuous reinforcement (CRF) and fixed-ratio (FR) performance in mice, with nest material and food as reinforcers. In Experiment 1, nest material (paper strips) was presented on a series of FR schedules of increasing size, with the operandum located as close as possible to the reinforcer dispenser. Subjects compensated for increases in FR size by proportionately increasing their response output, but ratio strain occurred at low FR values. In Experiment 2, response rate was found to be inversely related to operant-reinforcer distance on a CRF schedule with nest material as reinforcer. In Experiment 3, food was presented on a series of FR schedules at two levels of deprivation, and with three operant-reinforcer distances. Operant-reinforcer distance was found to affect CRF response rate, degree of compensation for increases in FR size, and occurrence of ratio strain, but only when deprivation level was low. The results support the view that nest material and food share fundamentally similar reinforcing properties, but that nest material is a weaker reinforcer under normal test conditions.     

Visual Field asymmetries for verbal and dot localization tasks in monolingual and bilingual subjects

Visual Field asymmetries for verbal and dot localization tasks were examined in monolingual and bilingual subjects. Consistent right-visual-field advantages were found for verbal material in all groups, although bilingual subjects showed a reduced laterality for their second language in comparison with their native language, Monolingual subjects displayed left-visual-field advantages on the dot localization task, but no consistent asymmetries were shown by the bilingual subjects. The overall pattern of results is consistent with left-hemisphere involvement for the processing of verbal material, but the heterogeneity of performance on the dot localization task suggests that processing of such a task may be influenced by subjects' linguistic backgrounds.     

The effects of S-R uncertainty in the PRP paradigm: A reply to Kantowitz

Karlin and Kestenbaum (1968) reported a series of apparently complex interactions between S-R uncertainty and RT in an experiment using the psychological refractory period paradigm. McLeod (1977) showed that these effects could be predicted by a parallel processing limited capacity model. Kantowitz (1978) criticised that paper on the grounds that it paid insufficient attention to the predictions of response conflict theory and made no mention of errors.It will be shown (a) that response conflict theory, as described by Kantowitz, fails to predict the effects found by Karlin and Kestenbaum (b) that the comments about errors miss the point of McLeod (1977) (c) that in his final section Kantowitz falls into an old trap which awaits the unwary analyser of PRP data.     

Vocational maturity in adulthood: Toward turning a model into a measure

It is postulated that adult vocational maturity needs to be assessed because of the changing developmental tasks encountered during the course of a career. Vocational maturity having been found to be multidimensional, existing undimensional inventories of adult vocational maturity are considered of limited although demonstrated validity. Relevant theories of adult vocational development and adjustment are reviewed. Super's proposed adult vocational maturity model is examined for the promise that it offers and for the problems that arise in developing a multidimensional measure of vocational maturity. A way of surmounting these problems is proposed as a basis for work now being undertaken.     

Cue selection in verbal discrimination learning of retarded subjects.

A series of experiments was conducted to examine cue function in trigram verbal discrimination learning by retarded subjects. The issue was to determine the factors that control attention in this type of learning situation. The two variables of chief interest were trigram meaningfulness and reinforcement history. The major general conclusion was that retarded subjects employ complex cue selection strategies in solving a verbal discrimination involving compound verbal stimuli. Major findings were as follows: (a) Retarded subjects exhibit a response bias in favor of words over nonsense trigrams; (b) relatively little active cue selection based on meaningfulness was observed; (c) a compound stimulus discrimination was more difficult to learn than a discrimination involving single verbal stimuli; (d) compound and single stimuli may be processed differently in original discrimination learning; (e) cue position probably controls attention in compound discrimination learning; and (f) a frequency theory of verbal discrimination learning is supported by these data.     

Naming in aphasia: Interacting effects of form and function

The naming difficulties of Broca's and anomic aphasics were explored in relation to a recently developed model of the normal mental lexicon which stresses the importance of integrating perceptual and functional information in the act of naming, and equally stresses the inherent vagueness of conceptual categories based on such information. Subjects were shown line drawings of various food containers varying in physical features such as height and width; they were required to select a name for the object from a multiple choice list (cup, bowl, or glass). Prototypical as well as nonprototypical objects were shown. The Broca's aphasics showed relatively normal naming profiles. In contrast, the posterior patients were unable to integrate perceptual and functional information and were insensitive to the fuzzy boundaries between conceptual categories. The results obtained for the posterior patients are interpreted as reflecting an impairment in the underlying conceptual organization of the lexicon rather than retrieval difficulties.     

Errors in children's subtraction

Many of the errors that occur in children' subtraction are due to the use of incorrect strategies rather than to the incorrect recall of number facts. A production system is presented for performing written subtraction which is consistent with an earlier analysis of the nature of such a cognitive skill. Most of the incorrect strategies used by schoolchildren can be accounted for in a principled way by simple changes in the production system, such as the omission of individual rules or the inclusion of rules appropriate to other arithmetical tasks. The production system model is evaluated against a corpus of over 1500 subtraction problems done by 10-year olds and is shown to account for about two-thirds of the (nonnumber fact) errors. It also provides an alternative, simpler interpretation of the subtraction errors analysed by Brown and Burton (1978). Some implications for teaching are discussed.     

Commentary on social class differences in sociodramatic play in historical context: A reply to McLoyd

Historical origins of the research on the cultural correlates of imaginative behavior by the Israeli psychologists Feitelson, Smilansky, and Eifermann are presented. It is argued that despite McLoyd's searching analysis of the deficiencies in studies which attempt to relate level of imaginative play to social class, those earlier cross-cultural studies, together with some 50 years of prior research on social class and play in general, provide a context which gives support to those studies despite their particular methodological deficiencies.     

Cerebral dominance in aphasia recovery.

This investigation studied the patterns of ear preference of a group of 25 aphasic adults through the administration of two verbal dichotic tests and retests over a 2-month interval of time. These dichotic tests were a Dichotic Digits Test (DDT) and a Dichotic Animal Names Test (DANT). Schuell's short test of aphasia was given twice over this interval to assess language recovery. Results indicated that as aphasics improve in language, cerebral dominance becomes more firmly established in the right cerebral hemisphere. The data in this study tend to support a dominance shift hypothesis in the recovery of language after aphasia.     

Imagery and verbal encoding in left and right hemisphere damaged patients

Neuropsychological aspects of imaginal and verbal encoding in memory were explored in two forced-choice recognition memory experiments with patients suffering from left and right anterior cerebral hemisphere damage. In the first experiment stimulus type and rate of presentation were varied. Predictions of patient performance based on the hypothesis that left anterior hemisphere pathology impairs verbal memory coding and right anterior hemisphere pathology impairs imaginal coding were confirmed. In a second recognition memory experiment for pictures of common objects, system-specific (imaginal or verbal) interference and distractor effects were demonstrated by analyzing the effects of interpolated tasks and the nature of false-recognition errors.     

The demonstration of capacity limitation

The study of divided attention has produced many apparent demonstrations of “capacity limitation.” Possible ambiguities in such demonstrations are considered for three major types of experimental situation: simultaneous inputs with separate responses; choice; and classification. Two issues emerge. First, demonstrations always rest on assumptions about process set, i.e., the set of internal processes by which the task actually is performed. Alternative process sets are considered for situations of each type. Second, a demonstration of capacity limitation is made either by increasing the number of simultaneous processes, or by changing the bias between them. In either case effects unrelated to capacity limitation may influence the results. If several processes contribute to a single response, some performance decrement must accompany an increase in their number, simply through the increased overall chance for error. If the subject is biased toward one alternative in a choice or classification situation, the benefits enjoyed by this alternative may reflect not a preferential allocation of attentional capacity, but simply a willingness to decide in favor of this alternative with relatively little evidence.     

Retention of verbal information by rehearsal in relation to the fluency of verbal output in aphasia

The purpose of the present study was to determine if aphasic subject groups differentiated by the fluency of their verbal output employed rehearsal as a strategy for maintaining verbally coded information in primary memory. A task based upon the Brown-Peterson paradigm was administered to 10 fluent aphasic patients, 10 nonfluent aphasic patients, 10 right-brain-damaged patients, and 10 nonneurological patients. The findings indicate that the nonfluent aphasic patients did not rehearse the verbal information while the fluent aphasic, right-brain-damaged, and nonneurological patients did rehearse. In addition, both fluent and nonfluent aphasic patients encoded significantly less information into the memory system initially and performed worse on the task overall than right-brain-damaged and nonneurological patients.     

Neologistic jargon aphasia: A case report

This study examined aspects of speech produced by an aphasic subject with neologistic jargon. Grammatical category, syllabic structure, and phonemic characteristics of neologisms, paraphasias, and correct productions were analyzed and compared. Results tended to confirm an anomic component in this type of aphasia and to support a role for the postactivation of phonemic units from prior utterances in the phonemic composition of some neologistic productions. In opposition to prior claims, however, the results also showed a striking similarity between neologisms and paraphasias, suggesting that similar mechanisms may be involved in both types of aphasic error.     

Relation of the verbal transformation and the phonemic restoration effects

This study examined the relationship between illusory changes of repeated words (“verbal transformations” or VTs) and illusory presence of phonemes replaced by noise (“phonemic restorations” or PhRs). Separate groups of 20 subjects were each presented with one of four taped variations of the repeated stimulus word “magistrate”: stimulus intact (MAGISTRATE); speech sound “s” removed and replaced with a silent gap (MAGI TRATE); speech sound “s” removed and replaced with a louder extraneous sound (MAGI¹TRATE); syllable “gis” removed and replaced with a louder extraneous sound (MA⁷¹TRATE). The stimuli MAGI¹TRATE and MA⁷¹TRATE evoked PhRs, and with these stimuli, the phonetic changes corresponding to VTs were concentrated at the perceptually restored portions of the word. It is suggested that both PhRs and VTs are related directly to perceptual processes employed normally for the correction of errors and resolution of ambiguities in speech. Other effects of PhRs upon VTs are described and implications of these findings for mechanisms underlying speech perception are discussed.