Reinforcement expectancy and trial spacing effects in delayed matching-to-sample by pigeons

Four experiments assessed the role of reinforcement expectancies in the trial spacing effect obtained in delayed matching-to-sample by pigeons. In Experiment 1, a differential outcome (DO) group received reinforcement with a probability of 1.0 for correct comparison responses following one sample stimulus and a probability of 0.2 for correct comparison responses following the other sample stimulus. The nondifferential outcome (NDO) group received reinforcement with a probability of 0.6 for correct responses to either stimulus. While matching accuracy was higher for the DO group than for the NDO group, both groups showed an equivalent decline in accuracy as the intertriai interval (ITI) duration was decreased. However, within the DO group, ITI duration affected performance on low-probability-of-reinforcement trials but not on high-probability-of-reinforcement trials. In Experiment 2, delay interval (DI) duration was 5, 10, or 15 sec and accuracy was higher for the DO group than for the NDO group at all DI durations. In addition, accuracy decreased similarly on high- and low-probability-of-reinforcement trials for the DO group as DI was increased. In Experiment 3, all birds were studied under DO conditions and ITI duration was manipulated along with DI duration. At the short DI duration, decreasing ITI duration had a detrimental effect on low-probability-of-reinforcement trials but no effect on high-probability-of-reinforcement trials. At the long DI duration, decreasing ITI duration had detrimental effects on both types of trials. In Experiment 4, unsignaled ITI reinforcers disrupted accuracy when the DI was long and when the ITI was short. The applicability of scalar expectancy theory to these data is discussed.     

Temporal discrimination factors in the delayed matching-to-sample task in monkeys

The temporal discrimination hypothesis (TDH) of delayed matching-to-sample (DMTS) stresses the animal’s ability to discriminate which choice-stimulus alternative has appeared most recently as sample. Thus, the emphasis is placed on discriminative processes, temporal in nature, rather than on the traditional trace or buffer storage mechanisms of short-term memory. Some of the predictions of the TDH were tested within the context of the DMTS task. Experiment I showed that the difficulty of sample-stimulus sequences could be predicted by the TDH. Experiment II showed DMTS performance to be an increasing function of the number of sample stimuli employed, a result predicted by the TDH, but not by a traditional proactive interference interpretation. The results demonstrate the importance of temporal discriminative processes in DMTS. The possibility for a simpler theoretical approach to memory, in general, is discussed.

     

Control of delayed matching-to-sample performance using directed forgetting techniques

Pigeons acquired a successive delayed matching-to-sample task at a delay interval of 4 sec. Instructional stimuli were interpolated in the delay interval signaling the occurrence (R-cue) or nonoccurrence (F-cue) of comparison stimuli, a procedure modeled after the directed forgetting techniques commonly used in human memory studies. Accuracy on probe trials (in which comparison stimuli were presented following F-cues) was reduced relative to performance on standard training trials in which R-cues signaling the occurrence of comparison stimuli appeared in the same temporal location. The extent of the reduction in accuracy depended on the temporal location of the F-cues, the reduction being greater when the cue was more remote from the comparison stimuli. Examination of retention interval keypecking revealed a strong correlation between matching performance and retention interval responding.     

Retroactive interference and rate of forgetting in delayed matching-to-sample performance

Previous evidence suggests that a disruptive stimulus presented during the delay interval of a delayed matching-to-sample trial increases the rate of forgetting by pigeons. However, disruptive events have generally been presented for a period of time proportional to the delay interval. Thus, the observed increase in forgetting may be the result of greater exposure to these events at longer delays than at shorter ones. This possibility was examined by comparing the effects of houselight illumination for the entire delay, half the delay, or a constant 1.5 sec of each delay on pigeons’ delayed matching-to-sample accuracy. Presenting the houselight for a period of time proportional to each delay (i.e., the entire delay or half the delay) impaired accuracy more at longer delays than at shorter delays. By contrast, when the houselight was illuminated for 1.5 sec, irrespective of delay length, there was a greater impairment in accuracy at shorter delays than at longer delays. Thus, the increased rate of forgetting previously reported in the literature may be the result of unequal application of a disrupting stimulus across delays.     

Influence of intertrial interval duration on the intertrial agreement effect in delayed matching-to-sample with pigeons

Accuracy on even-numbered trials was assessed as a function of (1) the relation between the sample on the immediately preceding trial and that on the current trial and (2) the length of the intertrial interval (ITI) that intervened between odd- and even-numbered trials. A relatively long interval intervened between pairs of trials in the clustered-dyads procedure, whereas this interval was equal to the ITI in the massed-trials procedure. Both procedures revealed an intertrial agreement effect in that accuracy was higher when the sample on the immediately preceding trial was identical rather than opposite. A decrease in the magnitude of this effect at longer ITIs was apparent only in the clustered-dyads procedure. The insensitivity of the intertrial agreement effect to variations in ITI in the massed-trials procedure may reflect floor effects and the carryover of memory from multiple prior trials that mask the true magnitude of the intertrial agreement effect at short ITIs.     

Within-session changes in responding during delayed matching-to-sample and discrimination procedures

Two experiments examined within-session changes in responding during discrimination procedures. In Experiment 1, rate of responding changed significantly within sessions during symbolic delayed matching-to-sample tasks when the delay between the stimulus and the choice period was short (1–5 sec), but not when it was long (8–12 sec). The percentage of responses that were correct did not change within sessions. In Experiment 2, response rates increased and then decreased within sessions during both S1 and S2 when successive discrimination procedures provided high, but not low, rates of reinforcement. Discrimination ratios sometimes increased within sessions. These results question two potential definitions of attention as explanations for within-session changes in response rates. They are more compatible with explanations based on concepts such as arousal, satiation, habituation, and interfering responses.     

Sample duration and type of stimuli in delayed matching-to-sample in rhesus monkeys

Two experiments were performed to determine the effect of sample duration (0.1, 2, and 4 sec), delay interval (.03, 4, 8, 16, and 32 sec), and type of stimulus (color and shape) on the matching performance of rhesus monkeys. In Experiment 1, the 15 possible delay-duration combinations were randomly presented in blocks of 15 trials. In Experiment 2, each duration was held constant and the five delays randomly presented. Then each delay interval was held constant with the three durations randomly varied. Matching performance increased as sample duration increased (ps < .01 and .005), while length of delay did not significantly affect performance. The type of stimuli paired in the matching test significantly affected performance (ps < .05 and .10) with the shape/shape choices leading to the poorest performance. Stimulus discriminability and amount of training with brief sample durations were implicated as significant determinants of matching performance.     

Pigeons’ short-term memory for temporal and visual stimuli in delayed matching-to-sample

In the present experiment, we compared directly pigeons’ short-term memory of temporal and visual stimuli in a delayed matching-to-sample task. The sample stimuli consisted of red and green lights presented for 5 and 30 sec, followed by a retention interval and blue and yellow comparisons. For subjects in the visual group, duration was irrelevant and the color of the sample was the conditional cue. For animals in the temporal group, color was irrelevant and duration of the sample was the conditional stimulus. The results showed that acquisition of the matching task was faster and accuracy was higher in the visual than in the temporal group. More importantly, memory of either sample generally declined at a similar rate when the duration of the retention interval was increased and when the intertrial interval was reduced. Taken together, the results indicate that with 1–8-sec retention intervals, short-term memory for temporal stimuli is similar to that found with color-visual samples. The findings are discussed in terms of retrospective and prospective processing.     

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

In three experiments, we examined how matching-to-sample by pigeons is affected by discrimination versus nondifferential training between the matching stimuli. In Experiment 1A, pigeons responding differentially to the sample stimuli off-baseline acquired accurate matching performances more rapidly than did pigeons responding nondifferentially to those same stimuli. In Experiment 1B, tests involving reversal of the off-baseline requirements demonstrated that the birds were primarily controlled in their matching choices by the sample stimuli. The results of Experiment 2 showed that off-baseline nondifferential training did not retard acquisition relative to comparable training between stimuli unrelated to the matching task. Together, these results suggest that discrimination training can facilitate matching acquisition by enhancing attention to the sample stimuli.     

不同任务投入量对英语词汇习得的影响

在英语学习中,词汇的掌握起着重要的作用。不同的学习任务会对词汇附带习得产生不同的影响。任务投入量越大,词汇习得和保持的效果越好。本文基于"投入量假设"这一基本原理来探讨在阅读中,不同的任务投入量对词汇附带习得的影响。     

The influence of stimulus attributes on duration matching-to-sample in pigeons

A duration matching-to-sample procedure was used to examine the influence of signal properties on temporal estimation and working memory. The results indicated that pigeons responded to durations of a light as if they were longer than equal durations of the absence of the same light, but delay performances did not differ between the two sample types. Similarly, pigeons responded to durations of a bright white light as if they were longer than equal durations of a dim red light, but again, delay performances did not differ between the two sample types. These results are discussed in terms of theoretical issues pertinent to timing, attention, and working memory.     

个体差异中的动机因素对二语习得的影响

个体差异是客观存在的个体因素,个体差异因素中包括认知风格、个体智商、学习动机、学习风格和学习策略等等个体差异因素,其中最主要的还是学习动机。而这一因素在很大程度上影响着第二语学得,对英语的教学也起着至关重要的作用。该文主要论述的是国内外对动机类型,动机对第二外语习得影响的研究以及激励学习动机的策略。     

The effects of incidental teaching on vocabulary acquisition by young children

The effects on vocabulary acquisition of child-initiated versus adult-initiated instances of adult labeling were studied. 16 monolingual, English-speaking preschool children were exposed to a Spanish-speaking adult. In order to have access to toys placed out of their reach, children had to request the toys in Spanish. For the experimental group, adult labeling occurred when the children expressed interest in the toy. Control group children were yoked temporally to experimental group children for the purpose of adult labeling. Thus, adult labeling for the control group was randomly related to the children's expressions of interest. Although both groups of children learned some Spanish words, children in the experimental group produced significantly more Spanish words during the training sessions and showed superior performance on posttraining tests of Spanish production. Levels of comprehension of the Spanish words were equivalent for both groups. Results are interpreted in the context of the literature on "incidental teaching" and are viewed as demonstrating the critical role in language acquisition of the timing of exposure to language models.     

Effects of sample duration and spaced repetition upon delayed matching-to-sample in monkeys (Macaca arctoides andSaimiri sciureus)

Delayed matching-to-sample was used to study the effects of sample presentation time and spaced repetition upon delayed matching accuracy in one stumptail monkey and three squirrel monkeys. It was found in Experiment 1 that presenting the sample stimulus for 0.5 sec led to lower matching accuracy than was the case with longer presentation times of 2.5, 5.0, and 10.0 sec. Experiments 2 and 3 investigated the effects of temporally spacing the presentations of the sample stimulus. It was found that spaced repetition led to a deterioration of performance relative to massed repetition. These results are similar to the findings of experiments with pigeons and are contradictory to several previous experiments with monkeys or apes which found no effect of presentation time and a facilitative effect of spaced repetition. It is suggested that the use of monkeys inexperienced in short sample duration matching and tested in operant chambers using a limited set of noncomplex stimuli may be responsible for the discrepancies between these results and those of other experiments with primates.     

The effects of instructional method upon the acquisition of inquiry skills

This study investigated the effects of Guided Discovery vs. Didactic methods of instruction upon the acquisition of certain inquiry skills. At the same time, the effects of method on the attainment of factual-conceptual achievement was assessed. Hypotheses of no interaction of the methods variable with the learner variables—sex, measured intelligence, creativity, interest in science, general scholastic achievement, and science achievement—were also tested. The sample consisted of 140 8th-grade students. The duration of the experimental unit was six weeks. The subject matter was the same for each, “Early Man in America.” The results favored the Didactic group for the factual-conceptual achievement and the Guided Discovery for the acquisition of inquiry skills. However, in the latter there was an interaction of method with levels of measured intelligence and achievement.     

The effects of conditioned taste aversions on the acquisition and maintenance of schedule-induced polydipsia

Conditioned taste aversions produced a moderate, but transient, suppression of schedule-induced polydipsia. This suppression was greater and longer lasting when rats were offered a choice between water and the previously poisoned solution on the polydipsia baseline. A final experiment demonstrated that taste aversions were more effective in suppressing schedule-induced consumption when superimposed on a developing schedule-induced drinking baseline as opposed to a stable pattern of schedule-induced drinking. It was suggested that schedule-induced polydipsia is insensitive to conditioned taste aversions. This conclusion was discussed in terms of schedule-induced alcohol consumption and its potential as an animal model of alcoholism.     

Complexity and lexicality effects on the acquisition of Spanish spelling

This study investigated how Spanish orthographic code complexities influence learning to spell. Word and pseudoword dictation tests were carried out by 208 first- to fourth-grade students. Items included the following orthographic code complexities: digraph, contextual effect, position effect, letter H, inconsistency, and stress mark. The results revealed effect of grade and type of complexity on spelling performance. The type of complexity also interacted with grade and lexical value of the type of items (word vs. pseudoword). It seems that children acquire spelling skills early in terms of phoneme–grapheme correspondence rules, but lexical knowledge develops more slowly. The importance of lexical knowledge is highlighted, as well as the need of prosodic knowledge for the stress mark.     

Errors by macaques performing trial-unique delayed matching-to-sample: A function of memory per se or of distinguishing between the subsequent choices?

In trial-unique delayed matching-to-sample the animal must (1) remember the item given as the sample, and (2) subsequently distinguish it from a second item to make a match. With rather short delays, even very well trained monkeys continue to make errors on this task. The question is whether these errors arise as a consequence of poor memory per se, or whether inadequate memory makes the sample difficult to distinguish from the alternative. This question was examined using pairs of items presented on multiple occasions. The role of sample was systematically interchanged between the items forming a pair. Errors were found to be well correlated between trials in which the same item served as sample, but essentially uncorrelated when those trials were compared with trials having the other item as the sample. For example, if A and B were paired items, results of trials in which A was selected as the sample were well correlated with other trials using A as the sample (run on other days); however, trials using A as the sample were uncorrelated with trials using B as the sample, even though the comparison pair (A and B presented together) was identical. These results suggest that the monkeys’ errors are not dependent on the distinguishability of the comparison pair, despite a “faded” memory on which to base the distinction.