Tactile short-term memory

Subjects tried to recall the location of a tactile stimulus on the underside of the forearm after delays of 0, 3, 5, 10, 15, 30, 45 and 60 sec. When “rehearsal” was prevented by requiring subjects to count backwards during the delay, accuracy of recall decreased systematically reaching an asymptote after 45 sec. When subjects were left free to “rehearse,” this did not affect the decline in accuracy over the first 10 sec. Between 10 and 15 sec. there was a significant increase in accuracy followed by a slow decline which had not reached asymptote by 60 sec. It is suggested that tactile STM (short-term memory) depends on two processes, a fading sensory trace which is unaffected by distraction and a less labile system which does not appear to be verbal but which depends on “rehearsal.”     

The effect of two schedules of primary and conditioned reinforcement

Of 23 pigeons, 11 received continuous reinforcement for key pecking, and 12 received an FR 10 schedule of reinforcement. The birds were then tested without food, but with potential conditioned reinforcers presented either on the same schedule as in training, on the other schedule, or not at all. Each bird in the subgroup trained on CRF and tested with S^r's at FR 10 not only gave more responses in testing than did each bird in both subgroups receiving no S^r's, but also gave more responses than did each bird in the S^r subgroup receiving CRF training and S^r's at CRF. Cumulative records are presented to show the effects of different schedules of conditioned reinforcers.     

A model for detection and recognition with signal uncertainty

A model for signal detectability suggested by Luce is extended to situations in which the observer is uncertain of some important characteristic of the signal, such as frequency. By making a single assumption concerning the observer's covert response behavior, two solutions are obtained corresponding to qualitatively different behavior. Decrements in detectability and in recognition with uncertainty are shown to be particular functions of discriminability and detectability of the stimuli in other situations. Relevant experimental data are considered.This work was supported by grant NSF-G5544 from the National Science Foundation. The author is indebted to R. Duncan Luce for critical discussion of the content and helpful suggestions concerning the form of this paper. Useful comments have been made by David M. Green, Francis W. Irwin, Roger M. Shepard, and W. P. Tanner, Jr.     

The prediction of adjustment at age 7 from activity level at age 5

One-hundred and ninety-two children (equally split between boys and girls) were studied when they were 5 years old in two settings, school and home. The children were observed in playgroups and at home, and were rated on activity level by their parents on the Rothbart Child Behavior Questionnaire. At age 7, the children were tested in our laboratory on the Harter Test of Perceived Competence and on an achievement task, and parents filled out the Child Behavior Checklist, the Child Behavior Questionnaire, and the Conners Parent Rating Scale. Home observations of activity level were significantly related to parent ratings of activity level, but not to school observations. Activity level at age 5 was related to parents' ratings of aggression and hyperactivity and to girls' learning problems at age 7. Activity level was not related to the children's self-perceived competence, but mothers' rating of high activity level at age 5 was related to low reading comprehension at age 7.Preparation of this paper was supported in part by the Center for Research for Mothers and Children, NICHD, U.S. PHS grant HD 19739 to Beverly I. Fagot.     

Why believe what people say?

The basic alternatives seem to be either a Humean reductionist view that any particular assertion needs backing with inductive evidence for its reliability before it can retionally be believed, or a Reidian criterial view that testimony is intrinscially, though defeasibly, credible, in the absence of evidence against its reliability.Some recent arguments from the constraints on interpreting any linguistic performances as assertions with propositional content have some force against the reductionist view. We thus have reason to accept the criterial view, at least as applied to eyewitness reports. But these considerations do not establish that any rational enquirer must have the concept of other minds or testimony. The logical possibility of the lone enquirer, who uses symbols and thereby expresses some knowledge of his world, remains open — but it is a question we have no need to pronounce upon.The practice of accepting observation-statements is in fact extended to chains of testimonies believed to start in perception or in some other kind of justification, but the arguments for doing this are not so clear.I am indebted for helpful discussions of earlier versions of this paper to audiences at Macquarie University (where I was kindly given research facilities), at the conference of the Australasian Association for Philosophy in Sydney in 1990, at St. Andrews, and also to a referee for this journal.     

Combining quantitative and qualitative methods in evaluating a course of family therapy

This paper reports on the use of a single case (A-B) design, with multiple measures of first and second order change and family satisfaction. A within-session process analysis was also made. Second order change was found to relate most clearly to the process of sessions. The single case design and process study is easy to apply in practice and is a potential response to clinical audit. The problems of combining quantitative and qualitative approaches are discussed.     

Reference in single sentences and in texts

This study investigated the comprehension and production of reference terms in both sentences (Experiments 1 and 2) and texts (Experiments 3 and 4) using a sentence completion task. In Experiments 1 and 2, the use of a sentence-level strategy (subject assignment) was investigated. In Experiments 3 and 4, the use of a text-level strategy (topic assignment) was also investigated. There was a clear preference for continuing the sentences by referring to the subjects of the sentences regardless of the availability of gender cues, in both single sentences and in texts. There was also an influence of the topic of each text on both the choice of referent and the type of reference term used. However, the choice of reference term was affected by the number of potential antecedents in the preceding text. Overall, the results suggest that the sentence subject is a salient item in working memory. This salience is increased if the sentence subject is also the textual topic. In addition, it appears that the presence of a pronoun in a text triggers a specific strategy to assign the pronoun to the (salient) sentence subject.This work is based on a doctoral dissertation submitted by R. A. Crawley to the University of Durham and supported by the Medical Research Council of Great Britain.