Biomedical subjects
M E Bitterman
Publications and source records attributed to M E Bitterman.
Attempts to train goldfish to respond to magnetic field stimuli.
Two different conditioning procedures, one appetitive and the other aversive, were used in separate attempts to demonstrate response to magnetic fields in the goldfish, Carassius auratus. Our results lead us to question those of an orientation experiment by Becker, although we recognize the possibility that goldfish may be sensitive primarily to magnetic field direction rather than intensity and that their directional sensitivity may be evidenced most readily by orientation in the field.
The overlearning-extinction effect and successive negative contrast in honeybees (Apis mellifera).
In three experiments with free-flying honeybees, the previously discovered overlearning-extinction effect was replicated under different conditions and shown to depend on magnitude of reinforcement: The effect appeared in training with a 50% sucrose solution but not with a 20% solution. The results prompted a fourth experiment in which successive negative contrast was demonstrated: The animals were disturbed to find the 20% solution on a distinctive target that always before had been baited with the 50% solution. The conclusion is that the overlearning-extinction effect is an instance of contrast and can be understood in terms of frustration engendered by unrealized anticipation of reinforcement.
Classical conditioning of proboscis extension in honeybees (Apis mellifera).
Extension of the proboscis was conditioned in restrained honeybees with odor as the conditioned stimulus (CS) and sucrose solution--delivered to the antenna (to elicit extension of the proboscis) and then to the proboscis itself--as the unconditioned stimulus (US). In a first series of experiments, acquisition was found to be very rapid, both in massed and in spaced trials; its associative basis was established by differential conditioning and by an explicitly unpaired control procedure (which produced marked resistance to acquisition in subsequent paired training); and both extinction and spontaneous recovery in massed trials were demonstrated. In a series of experiments on the nature of the US, eliminating the proboscis component was found to lower the asymptotic level of performance, whereas eliminating the antennal component was without effect; reducing the concentration of sucrose from 20% to 7% slowed acquisition but did not lower the asymptotic level of performance; and second-order conditioning was demonstrated. In a series of experiments on the role of the US, an omission contingency designed to eliminate adventitious response-reinforcer contiguity was found to have no adverse effect on acquisition. In a series of experiments designed to analyze the resistance to acquisition found after explicitly unpaired training in the first experiments, no significant effect was found of prior exposure either to the CS alone or to the US alone, although the unpaired procedure again produced substantial resistance that was shown to be due to inhibition rather than to inattention; extinction after paired training was found to be facilitated by unpaired presentations of the US. The relation between these results for honeybees and those of analogous experiments with vertebrates is considered.
Second-order appetitive conditioning in goldfish.
Second-order appetitive conditioning was studied in a series of experiments on goldfish. The first-order conditioned stimuli were white lines of different orientations projected on a target, the second-order conditioned stimuli were diffuse colors projected on the target, the unconditioned stimulus was liquid food delivered through a nipple at the center of the target, and the measured response was target striking. In the first experiment, sustained second-order conditioning was demonstrated. Evidence of colon-line association then was sought without success in two further experiments--a sensory preconditioning experiment in which second-order pairings preceded the first-order pairings, and a first-order revaluation experiment in which responses to second-order stimuli were measured after reversal training with positive and negative first-order stimuli. The stimulus-response reinforcement principle affords the best interpretation of the second-order conditioning demonstrated here: Responding to a second-order stimulus is strengthened by a contiguous first-order stimulus that acquires reinforcing properties on first-order trials.
Modification of attention in honey bees.
Honey bees were trained in two consecutive two-dimensional (color-position) problems with one dimension (color or position) relevant and the other irrelevant in each problem. As in analogous experiments on dimensional transfer in rats and monkeys, performance in the second problem was more accurate when the relevant and irrelevant dimensions were the same as in the first problem than when they were interchanged. The results of further experiments suggest that the transfer is mediated by different modes of responding that develop in color and position problems rather than by some special process of dimensional selection, such as has been assumed to operate in vertebrates.
Incentive contrast in honey bees.
Bees trained to come to the laboratory for a 20% sucrose solution accept it readily, but bees trained with a 40% sucrose solution and tested with the 20% solution show a pattern of interrupted feeding that may last for several minutes. Bees trained with 20% and tested with 40% sucrose are undisturbed. When the animals are offered two samples of the 20% solution simultaneously, they drink to repletion from whichever they first taste on each visit, but if both a 20% and a 40% drop are offered the 20% solution is rejected after a single experience of the 40% solution. Although these results are analogous in many respects to incentive contrast effects found in mammals, they can be understood in sensory terms and do not require the assumption of learning about reward.
Intradimensional vs. extradimensional transfer in the discriminative learning of goldfish and pigeons.
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Blocking and overshadowing in two species of fish.
In Experiment 1, a mixed blocking-overshadowing effect of color on an auditory discrimination was demonstrated in goldfish. In Experiment 2 (with lines differing in color and angle), blocking of angle by color and of color by angle was demonstrated in goldfish, In Experiment 3 (again with lines differing in color and angle), overshadowing of angle by color was demonstrated in carp, but the same animals (like goldfish in a previous study) failed to show greater intradimensional than extradimensional transfer. These results are consistent with the hypothesis that blocking and overshadowing are general phenomena of vertebrate learning. They suggest also that the processes responsible for blocking and overshadowing are different from those which produce the dimensional transfer effect.
Autoshaping: further study of "negative automaintenance".
The key pecking of pigeons was autoshaped to three key colors paired with food in discrete trials. Then, the effects of three different color-correlated contingencies were compared: reward (presentation of food contingent on pecking), omission (presentation of food prevented by pecking), and extinction (no food). Two measures of performance were used: initial response (the number of trials with each color on which at least one peck was made) and multiple response (the total number of pecks per trial). In general, the reward color produced more pecking than the omission color, the omission color more than the extinction color, and the extinction color more than on blank trials with an unlighted key, although (relative to reward) omission produced a higher level of initial than of multiple responding. These results point clearly to the importance of stimulus-reinforcer continguity in the control of pecking.
Pavlovian analysis of avoidance conditioning in the goldfish (Carassius auratus).
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Reversal learning with singly presented stimuli in pigeons and goldfish.
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Differential reinforcement of other behavior (DRO): a yoked-control comparison.
After training to press a lever on a variable-interval 30-sec schedule, one group of rats was shifted to a differential-reinforcement-of-other-behavior 10-sec schedule, while a second group was shifted to a noncontingent yoked-control schedule that provided the same frequency and distribution of reinforcement. Then, both groups were extensively retrained on the variable-interval schedule, after which the first group was shifted to a series of differential-reinforcement-of-other-behavior 30-sec sessions alternating daily with variable-interval 30-sec sessions, while the second group was treated like the first on variable-interval days and yoked with the first as before on differential-reinforcement-of-other-behavior days. In both phases, response-decrement was more rapid and more marked in the differential-reinforcement-of-other-behavior animals than in the controls. The difference was due, at least in large measure, to sustainment of response in the control animals by adventitious reinforcement. All the differential-reinforcement-of-other-behavior animals developed "other" behavior-the same distinctive pattern of waiting at the foodcup-but there was no direct evidence that it contributed in any way to the decrement in lever pressing.
Interference and forgetting in bird and fish.
Retention in the pigeon and in the goldfish was measured 1 day or 2 weeks after the mastery of each of a series of color discrimination. The amount of forgetting in the pigeon increased with the number of prior problems and increased more rapidly at the longer than at the shorter interval. the amount of forgetting in the goldfish was independent, at both intervals, of the number of prior problems. These results point to the operation of different memory mechanisms in the two animals.
Learning in fish with transplanted brain tissue.
Material taken from fish embryos during gastrulation was implanted at prospective tectal sites in host embryos of the same age and species. When mature, the hosts were trained in a series of habit reversals. Two of six animals showed progressive improvement in reversal (a phenomenon not typically found in fish, but characteristic of higher animals), two showed unusually few errors, and two behaved normally. Differences in performance were correlated with differences brain structure.
Measurement of consummatory behavior in the fish.
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Reversal learning and forgetting.
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Two-dimensional discriminative learning in the pigeon.
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