Within-session reversal learning in rhesus macaques (Macaca mulatta) (original) (raw)
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Pigeons’ use of cues in a repeated five-trial-sequence, single-reversal task
Learning & Behavior, 2013
We studied behavioral flexibility, or the ability to modify one's behavior in accordance with the changing environment, in pigeons using a reversal-learning paradigm. In two experiments, each session consisted of a series of five-trial sequences involving a simple simultaneous color discrimination in which a reversal could occur during each sequence. The ideal strategy would be to start each sequence with a choice of S1 (the first correct stimulus) until it was no longer correct, and then to switch to S2 (the second correct stimulus), thus utilizing cues provided by local reinforcement (feedback from the preceding trial). In both experiments, subjects showed little evidence of using local reinforcement cues, but instead used the mean probabilities of reinforcement for S1 and S2 on each trial within each sequence. That is, subjects showed remarkably similar behavior, regardless of where (or, in Exp. 2, whether) a reversal occurred during a given sequence. Therefore, subjects appeared to be relatively insensitive to the consequences of responses (local feedback) and were not able to maximize reinforcement. The fact that pigeons did not use the more optimal feedback afforded by recent reinforcement contingencies to maximize their reinforcement has implications for their use of flexible response strategies under reversal-learning conditions.
Behavioral Neuroscience, 2021
Insight into psychiatric disease and development of therapeutics relies on behavioral tasks that study similar cognitive constructs in multiple species. The reversal learning task is one popular paradigm that probes flexible behavior, aberrations of which are thought to be important in a number of disease states. Despite widespread use, there is a need for a high-throughput primate model that can bridge the genetic, anatomic, and behavioral gap between rodents and humans. Here, we trained squirrel monkeys, a promising preclinical model, on an image-guided deterministic reversal learning task. We found that squirrel monkeys exhibited two key hallmarks of behavior found in other species: integration of reward history over many trials and a side-specific bias. We adapted a reinforcement learning model and demonstrated that it could simulate monkey-like behavior, capture training-related trajectories, and provide insight into the strategies animals employed. These results validate squirrel monkeys as a model in which to study behavioral flexibility.
Learning & Behavior
The midsession reversal task involves a simultaneous discrimination in which choice of one stimulus (S1) is correct for the first 40 trials and choice of the other stimulus (S2) is correct for the last 40 trials of each 80-trial session. When pigeons are trained on the midsession reversal task, they appear to use the passage of time from the start of the session as a cue to reverse. As the reversal approaches, they begin to make anticipatory errors, choosing S2 early, and following the reversal they make perseverative errors, continuing to choose S1. Recent research suggests that anticipatory errors can be reduced (while not increasing perseverative errors) by reducing the probability of reinforcement for correct S2 choices from 100% to 20%. A similar effect can be found by increasing the response requirement for choice of S2 from one peck to ten pecks. In the present experiments, we asked if a similar effect could be attained by increasing the number of stimuli that, over trials, could serve as S2. Instead, in both experiments, we found that increasing the number of S2 stimuli actually increased the number of anticipatory errors. Several interpretations of this result are provided, including the possibility that attention to the variable S2 stimuli may have interfered with attention to the S1 stimulus.
Midsession reversal learning: why do pigeons anticipate and perseverate?
Learning & Behavior, 2013
Past research has shown that when given a simultaneous visual-discrimination midsession reversal task, pigeons typically anticipate the reversal well before it occurs and perseverate after it occurs. It appears that they use the estimation of time (or trial number) into the session, rather than (or in addition to) the more reliable cue, the outcome from the previous trial (i.e., a win-stay/lose-shift response rule), to determine which stimulus they should choose. In the present research, we investigated several variables that we thought might encourage pigeons to use a more efficient response strategy. In Experiment 1, we used a treadle-stepping response, rather than key pecking, to test the hypothesis that reflexive key pecking may have biased pigeons to estimate the time (or trial number) into the session at which the reversal would occur. In Experiment 2, we attempted to make the point of reversal in the session more salient by inserting irrelevant trials with stimuli different from the original discriminative stimuli, and for a separate group, we added a 5-s time-out penalty following incorrect choices. The use of a treadle-stepping response did not improve reversal performance, and although we found some improvement in reversal performance when the reversal was signaled and when errors resulted in a time-out, we found little evidence for performance that approached the win-stay/lose-shift accuracy shown by rats.
Midsession reversals with pigeons: visual versus spatial discriminations and the intertrial interval
Learning & Behavior, 2014
Discrimination reversal learning has been used as a measure of species flexibility in dealing with changes in reinforcement contingency. In the simultaneous-discrimination, midsession-reversal task, one stimulus (S1) is correct for the first half of the session, and the other stimulus (S2) is correct for the second half. After training, pigeons show a curious pattern of choices: They begin to respond to S2 well before the reversal point (i.e., they make anticipatory errors), and they continue to respond to S1 well after the reversal (i.e., they make perseverative errors). That is, pigeons appear to be using the passage of time or the number of trials into the session as a cue to reverse, and are less sensitive to the feedback at the point of reversal. To determine whether the nature of the discrimination or a failure of memory for the stimulus chosen on the preceding trial contributed to the pigeons' less-than-optimal performance, we manipulated the nature of the discrimination (spatial or visual) and the duration of the intertrial interval (5.0 or 1.5 s), in order to determine the conditions under which pigeons would show efficient reversal learning. The major finding was that only when the discrimination was spatial and the intertrial interval was short did the pigeons perform optimally.
Journal of Human Evolution, 1973
Discrimination-reversal learning was assessed in nine rhesus monkeys (Macaca mulatta) using an automated learning-set apparatus which permitted the measurement of learning-set skills and analysis of the patterns of incorrect responding. The three animals who attained the highest reversal scores (High) were compared with the three animals which had the lowest reversal scores (Low) with respect to the relative frequencies of errors involving either a single wrong response or more than one wrong response (2-9 consecutive errors). The groups did not differ from each other in acquisition, whereas in reversal the High Group made more errors involving a single incorrect response and faver strings of consecutive errors. For the Low Group the relationship was reversed. These results suggest that the patterning of incorrect responses is an index of discrimination-reversal performance which may be useful in comparative studies of primate learning.
Behavioural Brain Research, 2011
In humans and several nonhuman animals, repetitive behavior is associated with deficits on executive function tasks involving response inhibition. We tested for this relationship in nonhuman primates by correlating rates of normative behavior to performance on a reversal-learning task in which animals were required to inhibit a previously learned rule. We focused on rates of self-directed behavior (scratch, autogroom, self touch and manipulation) because these responses are known indicators of arousal or anxiety in primates, however, we also examined rates of other categories of behavior (e.g., locomotion). Behavior rates were obtained from 14 animals representing three nonhuman primate species (Macaca silenus, Saimiri sciureus, Cebus apella) living in separate social groups. The same animals were tested on a reversal-learning task in which they were presented with a black and a grey square on a touch screen and were trained to touch the black square. Once animals learned to select the black square, reward contingencies were reversed and animals were rewarded for selecting the grey square. Performance on the reversal-learning task was positively correlated to self-directed behavior in that animals that exhibited higher rates of self-directed behavior required more trials to achieve reversal. Reversal learning was not correlated to rates of any other category of behavior. Results indicate that rates of behavior associated with anxiety and arousal provide an indicator of executive function in nonhuman primates. The relationship suggests continuity between nonhuman primates and humans in the link between executive functioning and repetitive behavior.
The Midsession Reversal Task with Pigeons: Effects of a Brief Delay Between Choice and Reinforcement
2020
OF THESIS THE MIDSESSION REVERSAL TASK WITH PIGEONS: EFFECTS OF A BRIEF DELAY BETWEEN CHOICE AND REINFORCEMENT During a midsession reversal task, the session begins with a simple simultaneous discrimination in which one stimulus (S1) is correct and the alternate stimulus (S2) is incorrect (S1+/S2-). At the halfway point, the discrimination reverses and S2 becomes the correct choice (S2+/S1-). When choosing optimally, a pigeon should choose S1 until the first trial in which it is not reinforced and then shift to S2 (win-stay/lose-shift). With this task pigeons have been shown to respond suboptimally by anticipating the reversal (anticipatory errors) and continuing to choose S1 after the reversal (perseverative errors). This suboptimal behavior may result from a pigeon’s relative impulsivity due to the immediacy of reinforcement following choice. In other choice tasks, there is evidence that the introduction of a short delay between choice and reinforcement may decrease pigeons’ impul...