The statistical evidence for negative transfer in part-whole free recall

A series of studies on part-whole free recall led to the conclusion that learning part of a list before learning the entire list produces negative transfer late in learning. The statistical evidence for this conclusion is shown to depend upon assumptions about (1) the asymptotic level reached and (2) the relative magnitude of the variance between conditions as compared to the variance of Ss within conditions. Evidence concerning these assumptions is reviewed, and it is argued that there was insufficient evidence to support a conclusion of negative transfer in part-whole free recall.     

Power and speed components of individual differences in letter matching

Several previous studies have reported a correlation (typically around −.30) between standardized verbal ability test scores and name identity minus physical identity reaction times (NI-PI) in a letter-matching task. This correlation has usually been thought to reflect the mutual dependence of both measures on long-term memory access time. The present research was designed to assess Carroll's (1981) suggestions that: (a) NI — PI may not be the optimal formula for predicting standardized test scores from letter matching data, and (b) NI — PI may actually be related to the speed rather than the power component of standardized tests. Fifty-one subjects previously tested with a standardized reading test participated in letter-matching and word-reading tasks. The latter tasks required subjects to read words and specially constructed pseudowords. Power and speed measures were derived from the word-reading tasks and the standardized test on theoretical grounds (and supported by a principal components analysis). The results supported both of Carroll's contentions. NI — PI reaction time was related more to speed than power and the NI — PI statistic (as usually used) was not the optimum formula for predicting standardized test scores.     

The word order problem in agrammatism : II. Production

This study demonstrates that agrammatic aphasics have difficulty describing relations that are signified by the order of noun phrases around verbs or prepositions. The word order deficit is found in a Sentence Order Task, in which written words must be arranged linearly to form a sentence, as well as in oral production. Ordering tendencies reflect factors like animacy or potency, rather than the systematic use of syntactic rules. These results point to a fundamental syntactic disorder in agrammatism.     

Semantic mechanisms in paralexia

This study explores the effects of semantic constraints on the occurrence of paralexic responses in two patients who tend to produce semantic errors in reading aloud. In the first experiment, semantic constraints were provided by using words as proper names (e.g., “brown” vs. “Sam Brown”), and in the second by using short, highly familiar phrases to restrict the meaning of the target word (e.g., the polar bear; green with envy). These constraints were found to be effective in reducing the frequency of paralexic errors.     

Studies of operant and reflexive key pecks in the pigeon

The duration of pigeons' key pecks was studied in three experiments. Experiment I revealed that key pecks early in exposure to continuous reinforcement were of short duration, as were key pecks observed on an omission procedure in which pecks prevented food delivery. Key pecks later in exposure to continuous reinforcement, and those that occurred on positive automaintenance procedures, were of long duration. In Experiment II, pigeons were exposed to fixed-interval and fixed-ratio reinforcement schedules, and durations were recorded separately for each quarter of each interval or ratio. On fixed interval, durations were shorter in the first quarter of each interval than in subsequent quarters; on fixed ratio, durations were longer in the first quarter of the ratio than in subsequent quarters. These data parallel observations of concurrent operant responding and salivation in dogs. In Experiment III, pigeons were exposed to a discrete trial, differential-reinforcement-of-low-rate 6-sec schedule. Durations of responses in the first 2 sec of the trial were substantially shorter than those of responses that occurred later. The data from all three experiments support the view that the pigeon's "key peck" actually consists of two subclasses of peck, one reflexive and one operant.     

COLLEGE STUDENTS AS CONTINGENCY MANAGERS FOR ADOLESCENTS IN A PROGRAM TO DEVELOP READING SKILLS1

Behavior-modification procedures and an individualized tutorial program were used to remediate reading skill deficits in seventh-grade adolescent subjects. Forty-two college students were trained as reading tutors and contingency managers to use reading diagnostic and remedial materials, and to develop contracts and reinforce positive verbal responses toward reading. Significantly greater increases in reading scores of experimental groups, compared to control groups, substantial improvement in target behaviors, and significant changes in verbalizations toward reading were observed after 10 weeks of treatment. Six-month followup studies showed that all groups had consolidated their gains and that grade scores continued to improve. The improvement of the experimental subjects remained significantly ahead of the control subjects.     

Failure to produce response variability with reinforcement

Two experiments attempted to train pigeons to produce variable response sequences. In the first, naive pigeons were exposed to a procedure requiring four pecks on each of two keys in any order, with a reinforcer delivered only if a given sequence was different from the preceding one. In the second experiment, the same pigeons were exposed to this procedure after having been trained successfully to alternate between two specific response sequences. In neither case did any pigeon produce more than a few different sequences or obtain more than 50% of the possible reinforcers. Stereotyped sequences developed even though stereotypy was not reinforced. It is suggested that reinforcers have both hedonic and informative properties and that the hedonic properties are responsible for sterotyped repetition of reinforced responses, even when stereotypy is negatively related to reinforcer delivery.