Attentional enhancement in matching-to-sample: Facilitation in matching acquisition by sample-discrimination training

The effects of paired kinesthetic movements on literacy skills acquisition with preschoolers

Students who fail to acquire foundational literacy skills during preschool are more likely to read below grade level average in elementary school and are at a heightened risk for future school failure, poverty, early mortality, and crime. The purpose of this study was to compare the effects and maintenance of and preference for paired kinesthetic movements (KM) to a traditional drill (TD) procedure on letter-sound correspondence and word recognition with 6 preschool children. In 6 of 11 evaluations, participants mastered the KM set in substantially fewer intervention sessions than the TD set. In 5 of 11 evaluations, participants mastered the KM and TD sets with little differentiation between the number of intervention sessions. No participant mastered the control set. Maintenance data demonstrate a higher number of correct responses for the KM condition across all weeks. Preference varied across participants and was not always consistent with the more effective intervention.

Discrimination training facilitates pigeons' performance on one-trial-per-day delayed matching of key location

Six pigeons were tested on a one-trial-per-day variant of delayed matching of key location. In one condition, a trial began with the illumination of a pair of quasi-randomly selected pecking keys in a large 10-key test box. Pigeons' pecks to one key (the sample) were reinforced with 8-second access to grain on a variable-interval 30-second schedule, whereas pecks to the other key (the distractor) had no scheduled consequences. In the second condition, the nonreinforced distractor was not presented. In both conditions, subjects were removed from the apparatus after 15 minutes and placed in a holding cage. Subjects were subsequently replaced in the box after a delay (retention interval) of 30 seconds and were reexposed to the illuminated sample and distractor keys for 1 minute. If a pigeon made more pecks to the sample during this interval, the distractor was extinguished and subsequent pecks to the sample were reinforced on the previous schedule for an additional 15 minutes. If, however, a pigeon made more pecks to the distractor, both keys were extinguished and the subject was returned to its home cage. For all subjects, matching-to-sample accuracy was higher in the first condition. In a second experiment, the retention interval was increased to 5, 15, and 30 minutes, and then to 1, 2, 4, 8, 12, and 24 hours. Most subjects remembered the correct key location for up to 4 hours, and in one case, up to 24 hours, demonstrating a spatial-memory proficiency far better than previously reported in this species on delayed matching tasks. The results are discussed in terms of the commonly held distinction between working and reference memory.

Effects of within-class differences in sample responding on acquired sample equivalence

Two experiments examined whether acquired sample equivalence in many-toone matching was affected by variation in sample-response requirements. In each experiment, pigeons responded on either identical or different response schedules to the sample stimuli that occasioned the same reinforced comparison choice (i.e., to the within-class samples). Transfer-of-control tests were then conducted to determine acquired equivalence, or lack thereof, between these samples. In both experiments, there was minimal or no evidence of acquired sample equivalence when pigeons responded differently to the samples within each common-choice class. By contrast, transfer was observed if pigeons responded (a) identically to all sample stimuli, or (b) identically to samples within each common-choice class (viz., to samples that occasioned the same reinforced choice) and differently to samples from different classes (viz., to samples that occasioned different choices). These results may help to explain the recent lack of evidence for response membership in pigeons' acquired equivalence (Urcuioli, Lionello-DeNolf, Michalek, & Vasconcelos, 2006). They also raise questions about the functional sample stimuli and about possible interactions between acquired equivalence and acquired distinctiveness.

Use of a differential observing response to expand restricted stimulus control

This study extends previous work on the use of differential observing responses (DOR) to remediate atypically restricted stimulus control. A participant with autism had high matching-to-sample accuracy scores with printed words that had no letters in common (e.g., cat, lid, bug) but poor accuracy with words that had two letters in common (e.g., cat, can, car). In the DOR intervention, she matched the distinguishing letters of the overlapping words (e.g., t, n, r) immediately prior to matching the whole words. Accuracy scores improved, and accuracy remained high when DOR requirements were withdrawn.

The role of common reinforced comparison responses in acquired sample equivalence

Different samples occasioning the same reinforced comparison response in matching-to-sample are interchangeable for one another outside of original training. The present studies were designed to verify the role of these common responses in producing acquired sample equivalence by explicitly varying the presence or absence of this commonality during training. In each of the two experiments, one group of pigeons made the same reinforced choice response following multiple sample stimuli, whereas controls either made different reinforced choices following each sample (Experiment 1) or reinforced choices after only two of four center-key stimuli (Experiment 2). Later, two of the original samples/center-key stimuli were established as conditional cues for new comparison responses, after which the ability of the remaining samples/center-key stimuli to occasion those new responses was assessed. Following common-response training, matching accuracy was higher on class-consistent than on class-inconsistent transfer tests, whereas accuracy in the controls was generally intermediate between these two extremes, a pattern similar to that reported in the human paired-associate literature. These findings confirm that occasioning the same reinforced choice response is one means by which disparate samples become functionally equivalent.

Reduction of stimulus overselectivity with nonverbal differential observing responses

Three individuals with mental retardation exhibited stimulus overselectivity in a delayed matching-to-sample task in which two sample stimuli were displayed on each trial. Intermediate accuracy scores indicated that participants could match one of the samples but not both of them. Accuracy in a baseline condition was compared to accuracy with a differential observing response procedure. This procedure prompted participants to make simultaneous identity-matching responses that required observation and discrimination of both sample stimuli. These observing responses were never followed by differential consequences. When observing responses were prompted, participants' accuracy scores improved. In a return to the baseline condition, when differential observing responses were no longer prompted, accuracy returned to intermediate levels. The results show that stimulus overselectivity can be greatly reduced by a behavioral intervention that controls observing behavior and verifies discrimination, but that exposure to such procedures alone may be insufficient for lasting benefits.

Effects of procedural parameters on response accuracy: lessons from delayed (non-)matching procedures in animals

The experimental analysis of behaviour in operant paradigms has identified numerous variables which affect performance. We will focus on the delayed (non-)matching tasks in order to illustrate the influence of procedural variables on acquisition and performance in operant tasks of cognitive function. Systematic variation of these parameters can help dissociate different cognitive processes which may be differentially affected by drug treatment or brain lesions. Use of different parameters, however, could equally account for controversial drug or lesion effects reported in the literature. Consideration of these factors will increase our understanding of the relative contribution of these and other features and parameters of the procedural arrangements to the final behavioural outcome.