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Biomedical subjects

M Jitsumori

Publications and source records attributed to M Jitsumori.

10 recordsLinked to original sources
PubMed1996

A prototype effect and categorization of artificial polymorphous stimuli in pigeons.

In a go-no-go discrimination task, pigeons were trained to discriminate artificial polymorphous stimuli differing along 3 six-valued features. Exemplars of each category were generated by systematic transformations of the features from a single stimulus, a base pattern (prototype). They were then tested for transfer to novel stimuli including the base patterns. The most pronounced discrimination occurred between the base patterns rather than between the extreme positive and negative stimuli. A distance-from-prototype rule and an additive integration of feature utilities or of feature frequencies are suggested to account for the prototype effect. In Experiment 2, pigeons were trained on a 2-key choice discrimination task, with the base patterns as conditional stimuli. Subsequent testing with distorted stimuli suggested that a distance-from-prototype model best explains the present findings.

Animals↗
PubMed1994

[Advances in the experimental analysis of behavior: issues of choice behavior, comparative cognition, and human language].

As the opportunity to contact with related areas has increased, the study of of the experimental analysis of behavior has experienced revolutionary changes. Some of the most active and important areas-studies of choice, comparative cognition, and human language--are reviewed to acquaint readers. Studies of CHOICE have linked to the molar theories of behavioral economics and behavioral ecology, which promoted research of choice by animals under uncertainty conditions. Further approach has been made to integrate the molar and molecular analyses on the basis of the ideas of behavior dynamics. COMPARATIVE COGNITION is a part of a larger field including cognitive science, behavioral neuroscience, and biological science. Recent developments, aided with a comparative perspective, made significant contributions to our understanding of the phylogeny and ontogeny of cognition. Advances in analysis of human behavior provided tools to study behavioral aspects of semantics, syntax, and pragmatics of HUMAN LANGUAGE. Using the paradigm of stimulus equivalence, the emergence of stimulus relations, stimulus-stimulus networks, hierarchical structure of verbal behavior, and other language-related behaviors have been investigated.

Choice Behavior↗
PubMed1994

Discrimination of artificial polymorphous categories by rhesus monkeys (Macaca mulatta).

Monkeys (Macaca mulatta) were trained to discriminate between sets of artificial stimuli such as those used by Jitsumori (1993) for pigeons and humans. The stimuli were arrays of symbols differing along three two-valued (positive or negative) dimensions. The discrimination required was between polymorphous categories in which a positive stimulus was defined by possession of any 2 out of 3 positive features. Of the 5 monkeys, 3 learned the discrimination much faster than did pigeons, but transfer to novel stimuli was less impressive than had been shown in pigeons. The 3 monkeys showed high levels of transfer to the stimuli that contained either all 3 positive or all 3 negative features, but 2 of the 3 monkeys failed to show transfer to stimuli that had 1 of the 3 features replaced with a novel one. Analysis of the monkeys' performance raised doubts on the additive integration of features but supported learning of feature combinations as a basis for the discrimination of polymorphous categories by this species.

Animals↗
PubMed1992

Directed forgetting of elements in compound samples.

Pigeons were trained in a delayed matching-to-sample procedure in which the sample stimuli consisted of a compound of color (red or green) and spatial location (left or right). A postsample cue (houselight on or off) signaled whether color matching or location matching would be required following the delay. In Experiment 1, the reduction in performance on probe trials (in which the houselight condition was reversed relative to that on regular trials) was greater for location matching than for color matching. The birds showed overt mediational behavior during the delays on location-matching trials. On color-matching trials, the birds exhibited behavior during delays that might have interfered with that mediational behavior. In Experiment 2, the houselight condition was changed shortly before presentation of the comparison stimuli on probe trials. Accuracy of location matching was reduced when the cue initially signaled color matching and was then changed to signal location matching, whereas matching accuracy was not reduced by a change in the opposite direction. Accuracy of color matching was reduced by a change in illumination level from dark to light, regardless of type of the relevant dimension signaled by houselight illumination. Discussion of these findings focuses on the variables critical to establishment of an effective cue to forget.

Animals↗
PubMed1990

Naming, rehearsal, and interstimulus interval effects in memory processing.

Recognition memory was tested for lists of 6 briefly (0.08 s) presented pictures at different interstimulus intervals (ISI) of 0.08, 1, and 4 s. Experiment 1 showed a 16% performance increase (ISI effect) for increasing ISI for travel slide but not kaleidoscope pictures. Experiment 2 showed that learning names for the kaleidoscope pictures then resulted in a substantial (20%) ISI effect, not attributable solely to the added exposure to the pictures. Experiment 3 required names, color evaluations, or blank stares during list-memory presentations. Interviews established that the most effective memory strategy was chaining the names together, followed by repeating the most current name, and in turn followed by reliance upon only the sensory experience. All groups in Experiments 2 and 3, independent of ISI effects, showed U-shaped serial position functions. Rehearsal is shown to be nonessential and cannot be the general cause of the primary effect of the serial position function.

Adolescent↗
PubMed1989

[Schedule sensitivity in human operant behavior: instructed versus shaped verbal behavior].

Presses on left and right buttons by undergraduate students occasionally produced points exchangeable for money, according to a multiple random-ratio random-interval schedule. During interruptions in the schedule, the subjects were required to fill out sentence-completion guess sheets about how they should press the buttons to gain the points available. Three of six subjects were instructed about the rules of button pressing (the instructed group), whereas the others received no instructions but their guesses were shaped with differential points also worth money (the shaped group). The schedule was changed so that button pressing relying on the instructed or shaped rules substantially decreased the available points in the contact condition but not in the no-contact condition. A schedule change in the no-contact condition produced no performance change in either groups. In the contact condition, shaped group subjects showed a performance change, whereas instructed group subjects did not until they temporarily encountered an extinction schedule. When the no-contact condition was reintroduced, sensitive responding occurred in the shaped group but not in the instructed group suggesting that prior experience in the contact condition increased the schedule sensitivity of the shaped group. The findings clearly demonstrated that responding was more sensitive to schedule changes when the rules were shaped than when they were instructed.

Adult↗
PubMed1989

Buildup and release from proactive interference in a rhesus monkey.

The potential of the buildup and release from proactive interference (PI) technique in the study of animal categorization was demonstrated with a rhesus monkey. A serial probe recognition task was used with a list of 4 consecutive slide pictures (upper screen) followed by a single probe picture (lower screen). The monkey moved a lever to indicate whether or not the probe was contained in the list. PI built over 40 consecutive trials tested with either flowers or primate faces. PI was released on category change and then built during 40 trials with the second category. The first 2 serial positions showed somewhat greater PI buildup and release, supporting conclusions from human studies that the effects occur primarily in secondary memory. A second experiment provided 2 replications of the main effect and showed through color border changes and elimination of color differences that color was not a critical feature.

Animals↗
PubMed1988

Long-term proactive interference and novelty enhancement effect in monkey list memory.

Serial-probe-recognition (SPR) performance by 2 monkeys deteriorated over several months of training. Three hundred and twenty different items were presented without repetition within a session (trial unique) but were repeated between sessions. The cause of the deterioration was identified as proactive interference (PI) due to repetitive use of items from day to day. Introduction of novel stimuli across days improved performance from 63% to 82% correct (Experiment 1). Tests with only probe items and no list items (Experiment 2) revealed that the monkeys were using a familiar/novel response strategy in combination with a relational strategy (relating the probe item to the list items) to further improve their SPR performance. Intermixing familiar baseline trials and novel transfer trials within a session (Experiment 3) encouraged the subjects to use a relational strategy, and it improved performance on baseline trials as well as on transfer trials. Possible qualitative similarity between the relational strategy and the familiar/novel response strategy is discussed along with theoretical implications of these findings for experiments which have used small number of repeating stimuli within a session.

Animals↗
PubMed1982

Memory for two stimulus-response items in pigeons.

Six pigeons served in a discrete-trial experiment on short-term memory. Combinations of three key positions and two ordinal positions, yielding six possible sequences of stimulus-response pairs, were used as lists of items. A retention interval separated list presentation from the test phase in which two (for Group 1) or three (for Group 2) keys were illuminated with either red or green light. A reinforcer was delivered if a subject pecked the key of the first item on a red trial and the key of the second item on a green trial. When the retention interval was lengthened from one to five or nine seconds, a systematic loss of stimulus control resulted. Lengthening the interval between items from one to eight seconds had a much smaller effect for the birds in Group 1, whereas a systematic loss of stimulus control was found in red trials for the birds in Group 2. The functional relations between choice accuracy and delay provided an empirical basis for analysis of what relations among temporal events can become discriminative stimuli.

Journal Article↗