Stimulus similarity and order as factors in visual short-term memory in nonhuman primates.

Rats performed a new delayed matching-to-sample task-the continuous nonmatching-tosample task. A variable number of trials with one stimulus alternated with trials with a second stimulus. A response on the trial following a stimulus change (nonmatch trial) was reinforced. Responses to repeated stimuli were never reinforced. Rats could maximize reinforcement by remembering across the intertrial interval which stimulus was presented on the previous trial. Sequential analysis indicated that interference from previous conflicting trials (proactive interference, PI) reduced response accuracy but did not affect retention: Accuracy was lower on trials following a nonmatch trial than on trials following repeated stimuli. Furthermore, accuracy increased as a function of the time between the to-be-remembered nonmatch trial and the previous interfering trial. However, neither time between trials nor the distance from a stimulus change affected the rate of decline in accuracy over the retention interval.

Section: Discussionmentioning

confidence: 99%

Effects of proactive interference on rats’ continuous nonmatching-to-sample performance

Pontecorvo

1983

“…In this version of DMTSS, the birds were required to peck the comparison stimuli in a particular order. Devine and Jones (1975) and Devine, Burke, and Rohack (1979) required their rhesus monkeys to respond in a "forward" order to the comparison stimuli-that is, a response to the comparison corresponding to the first sample (SI) followed by a response to the comparison corresponding to the second sample (S2) was reinforced. However, pilot testing revealed higher accuracy when the birds were required to respond in a "backward" S2-S1 order.…”

Section: Methodsmentioning

confidence: 99%

“…Other animals also have difficulty mastering this task. Devine, Burke, and Rohack's (1979) rhesus monkeys each required approximately 10,000 trials to reach the criterion level of accuracy, and that task was made easier for 1 monkey by the omission of sample sequences containing two samples from the same dimension (i.e., two colors or two shapes). In the present task, the same three stimuli (all colors) were used as both samples and comparison stimuli throughout training and testing.…”

Section: Accuracy Datamentioning

confidence: 99%

Delayed matching-to-successive-samples in pigeons: Short-term memory for item and order information

MacDonald

1993

Short-term memory for order information in pigeons was explored by using a delayed matchingto-successive-samples task (DMTSS). Experiment 1 indicated that pigeons can accurately report the order of two successively presented samples. Experiments 2, 3 and 4 specifically addressed the representation of order information in short-term memory. Experiment 2 showed that when the duration of the first sample (S1) was very long, or when the duration of the second sample (S2) was very short, order errors increased relative to baseline (S1 and S2 of equal duration), suggesting that memory strength plays an important role in the discrimination of order. The possibility that strength information is necessary for accurate DMTSS performance was tested in Experiments 3 and 4. Pigeons continued to match accurately when memory strength and order were uncorrelated.Previous research directed specifically at the processing of sequences of events has shown that animals can learn to discriminate and to produce sequences of temporally ordered stimuli. Sequence discrimination experiments require animals to discriminate a particular sequence of stimuli from several possible alternative sequences. Typically, responding after only one of many possible sequences is reinforced. The results of sequence discrimination studies have shown that animals can accurately discriminate two-and three-element sequences (e.g., Cowey & Weiskrantz, 1976;D'Amato & Columbo, 1988; Roitblat, Scopatz, & Bever, 1987;Terrace, 1987;Weisman & DiFranco, 1981;Weisman, Duder, & von Konigslow, 1985;Weisman, Gibson, & Rochford, 1984;Weisman, Wasserman, Dodd, & Larew, 1980). Sequence production studies require animals to respond to a set of stimuli in a particular order. The reinforced order remains constant across trials, although the configuration of stimuli varies randomly from trial to trial. A considerable amount of research has shown that pigeons can learn to produce sequences of up to five elements with no explicit intratrial feedback and can generalize this production to novel stimulus configurations (e.g., Straub, Seidenberg, Bever, & Terrace, 1979;Straub & Terrace, 1981; This research was part of a doctoral dissertation submitted by the author to the University of Alberta. It was supported in part by a NSERC postgraduate scholarship and by a University of Alberta Dissertation fellowship. Preparation of this article was supported by a NSERC Operating Grant to the author. Thanks to Douglas S. Grant, C. Don Heth, Marcia L. Spetch, Ron Weisman, and especially to Peter Urcuioli, for their valuable comments on previous drafts. Correspondence concerning this article should be addressed to Suzanne E. MacDonald, Department of Psychology, York University (Atkinson College), 4700 Keele St., Toronto, ON, Canada M3J IP3 (e-mail: suzmac@vml.yorku.ca). 1986a, 1986b, 1987, 1991 Terrace & Chen, 1991a, 1991b. In addition, pigeons can perform quite accurately on subsets of the training sequence, indicating that they do not simply learn stimulus-response chains in the original se...

“…Capaldi et al, 1980;Hulse, 1978), the role of interference in long-delay learning in animals (see, e.g., This research was supported by NSF Grant BNS 80-01171 to E. J. Capaldi. Lett, 1979), and the ability of animals to remember two or more events and their order of occurrence (e.g., Capaldi, 1964;Devine, Burke, & Rohack, 1979;Shimp, 1976).…”

mentioning

confidence: 99%

Serial order anticipation learning in rats: Memory for multiple hedonic events and their order

Capaldi

Verry

1981

107

Many characteristics of a series of discrete independent hedonic events may be remembered by rats in terms of, for example, how many events were rewarded and how many were nonrewarded. Such memory for multiple hedonic events, which has been shown to be a potent factor controlling instrumental responding, was examined here in five investigations employing serial anticipation learning in a runway. It was found that the ability of rats to remember the hedonic events reward and nonreward is highly developed, accurate, and quite resistant to forgetting and interference. Rats not only remembered a rewarded event and a nonrewarded event, but they also remembered the order in which the two events occurred. Rats remembered how many nonrewarded events there had been accurately enough to suggest that they were using some form of a counting mechanism. Rats exhibited little forgetting of eight prior discrete hedonic events, one rewarded followed by seven nonrewarded, even when these occurred over an interval of 20 min and involved considerable potential interference. In the serial learning situation employed here, marked primacy effects were obtained, earlier nonrewarded trials in a series being better anticipated than later ones. The primacy effect was found to depend upon the type of series employed. By assuming that stimulus generalizations occur between the multiple hedonic events remembered by rats, all anticipatory learning obtained here could be explained in considerable detail.