Wisconsin General Test Apparatus Research Articles

An investigation of number-concept appreciation in a rhesus monkey

In order to determine if nonhuman primates have some type of number-concept appreciation, the ability to form a concept of the third object in a row of three, four, five, six or seven objects was studied in an adolescent rhesus monkey. The problem was presented to the subject in a Wisconsin General Test Apparatus. Square wooden blocks, placed on a 45-hole formboard were used as the experimental stimuli. Position of rows of blocks was varied, either being placed in the center of the first row or randomly on the formboard. The subject learned to discriminate the third block in a row of blocks in a total of 62 days. The results of the present experiment indicate that monkeys can learn the concept of third. These results agree with those of other studies of number concept in nonhuman primates and lend further support to the idea that nonhuman primates have at least some type of number appreciation.

An involvement of acetylcholine in object discrimination learning and memory in the marmoset

Five marmosets ( Callithrix jacchus) were tested, using a Wisconsin General Test Apparatus, on a series of junk object visual discrimination tasks, including new learning, 24-hr reversal and 24-hr retention. The effects of administering the cholinergic receptor blocking agent, scopolamine either just before or immediately after the new learning task, or just before the 24-hr reversal and retention tasks, were assessed. Results suggest that scopolamine impairs new learning and impairs the encoding of new information in long term memory. Some evidence of a mild retrieval deficit under scopolamine was also seen, while state-dependent effects were not apparent.

Cholinergic learning deficits in the marmoset produced by scopolamine and ICV hemicholinium.

Common marmosets (Callithrix jacchus) were trained to perform daily position discrimination learning tasks in a Wisconsin General Test Apparatus. Acetylcholine receptor blockade with scopolamine was found to impair position learning. Testing on the day after scopolamine treatment suggested that a task learnt under scopolamine was not encoded into long term memory. Acetylcholine depletion achieved by the intraventricular injection of hemicholinium 4 h before testing resulted in a profound impairment of position discrimination learning. It is suggested that central acetylcholine depletion in primates may provide a useful model of senile dementia.

Visual recognition memory in squirrel monkeys

Squirrel monkeys (Saimiri sciureus) were trained on visual recognition memory tasks in a Wisconsin General Testing Apparatus with a trial-unique procedure that used 250 objects as stimuli. In Experiment 1, acquisition of a trial-unique delayed non-match-to-sample task (DNMS) was compared with acquisition of a trial-unique delayed match-to-sample (DMS) task. The DNMS task was learned in significantly fewer trials and with significantly fewer errors. Two animals in the DNMS group demonstrated highly accurate retention of the DNMS strategy despite an 11-month hiatus in experimental testing. In Experiment 2, the same procedures were used to study the learning of lists of 3, 5, 10, or 20 serially presented items. Although the animals were able to accurately remember lists of up to 20 items, there was no evidence of serial position effects.

Pretraining and learning: Are “adaptable” monkeys “bright”?

Two groups of rhesus (Macaca mulatta),two groups of cynomolgus (M. fascicularis),and one group of stumptailed monkeys (M. arctoides)were adapted to testing in the Wisconsin General Test Apparatus using a standardized procedure that produced an objective measure of the speed of adaptation (pretraining). Four of the groups were then given standard object-discrimination learning-set training. The fifth group, one of the groups of rhesus monkeys, was given delayed response training before the learning-set training and delayed matching-to-sample learning-set training after. Only performance on the delayed response task was correlated with speed of pretraining. The results suggest that differences in pretraining performance reflect primarily emotional and/or temperamental differences, whereas differences in learning-set performance reflect primarily differences in cognitive functioning.

Further consideration of the learning impairment after aceperone in the marmoset: Effects of the drug on shape and colour discrimination and on an alternation task

Ten marmosets ( Callithrix jacchus) learned to discriminate between pairs of small grey objects differing only in shape or small plain plaques differing only in colour, in a Wisconsin General Test Apparatus. Each day, each animal was presented with three consecutive visual discrimination problems in the order shape-colour-shape or colour-shape-colour. After aceperone, an α-noradrenergic antagonist, animals were impaired at learning the first but not the subsequent tasks of each trio. These results suggest that the previously observed impairment [10] on the first of a pair of object discrimination tasks after aceperone is a consequence of disruption of a mechanism common to both shape and colour discrimination learning. The fact that there is no impairment on task 2 in a dimension differing from task 1 suggests that the deficit is not one of attending to, or switching attention to, the appropriate visual dimension. Three further marmosets were trained to perform an alternation task and tested under aceperone. No impairment in performance was seen, suggesting that a variety of cognitive skills other than stimulus-reward association were intact. We conclude that the impairment following aceperone is a dysfunction of processes involved in association formation, but that it is one which is manifest only when the animal is faced with a type of task which has not recently been performed and that it can be overcome with persistence even when the animal encounters novel stimuli.

A new approach to the role of noradrenaline in learning: Problem-solving in the marmoset after α-noradrenergic receptor blockade

Nine marmosets ( Callithrix jacchus) were tested on a variety of visual discrimination learning tasks in a Wisconsin General Test Apparatus with or without α-noradrenergic receptor blockade achieved by the administration of aceperone. After aceperone, animals were found to be severely and consistently impaired at learning the first task of each test session and to be impaired on new and repeated reversal learning. They were, however, unimpaired on learning another similar task in each test session and on performance of a well-learnt-task. Results are interpreted as evidence for defective association formation which can be compensated for by suitable priming or practice.

Performance correlates of social behavior and organization: Social rank and complex problem solving in crab-eating macaques (M. fascicularis)

Seventeen male crab-eating macaques, drawn from two captive troops, were tested on a series of complex problem solving tasks in a Wisconsin General Test Apparatus (wgta). The animals were trained on a series of 6-trial object quality learning set problems followed by a series of 10-trial object quality learning set problems. They were then given problems in which the correct stimulus object was reversed part way through the problem. After the animals reached criterion on this task, the reversal learning set was then extinguished. High ranking animals made more intraproblem errors than low ranking animals on the 6-trial problems, but there was no relationship between social status and the rapidity with which the object quality learning set was established. Animals that received overtraining on the 6-trial problems transferred their learning virtually intact to the 10-trial problems; however, high ranking animals without overtraining made more errors than low ranking animals. On reversal learning and reversal extinction, high ranking animals made more errors on critical trials, indicating that they formed and extinguished the reversal set more slowly than low ranking animals. Object quality sets, as measured by trial-2 performance, were not affected by the reversal conditions.

An apparatus for automating object discriminations with pigeons.

Summary.-A simple motorized mechanism for repeated presentations of non-projected stimulus displays in visual discrimination experiments is described. Studies on the visual perceptual processes of animals have depended heavily on the use of planometric displays, either of some abstract form or pictures of objects. An increasing amount of research (Cabe, in press) has called into question the validity of the assumption that responses to planometric displays reflect adequately the processes which come into play when the animal subject is confronted with stereometric, three-dimensional displays. For organisms with well-developed manipulative abilities, devices such as the Wisconsin General Test Apparatus, or a variant of it, may be employed to test object discriminations. However, a major difficulty with the apparatus is the labor required to use it: an experimenter must manually change the display from trial to trial. With non-primate organisms, furthermore, a good deal of time and effort must be devoted to shaping an appropriate manipulative response. Automation of object (stereometric) discrimination problems would obviously be advantageous, particularly for use with 'visual' but not especially 'manual' organisms such

Pseudolearners in discrimination reversal.

This research investigated the shape of the acquisition and reversal functions in retardates' discrimination learning, with safeguards against suspected artifacts in other studies. A modified Wisconsin General Test Apparatus was used with 60 retardates in a 2 X 2 factorial design. Another 11 were classified as pseudolearners. The variables were the prereversal criteria and the number of irrelevant dimensions. After meeting criterion subjects were given 30 more trials for the detection of pseudolearners, but all received reversal training. Performance was stationary in both acquisition and reversal, suggesting all-or-none learning. For learners, differences of midreversal plateaus appeared which were opposite to predictions of the Zeaman and House (1963) theory. When pseudolearners were included, however, the plateau effect partially conformed to the theory.

Effects of caudate nuclei or frontal cortical ablations in cats and kittens: Paw usage

A modified Wisconsin General Test Apparatus was used to evaluate the paw usage of adult cats with bilateral aspiration lesions of the caudate nuclei, unilateral removals of the caudate, or bilateral removal of the frontal cortices. Lesions were inflicted either between 9 and 36 days of age of as adults (>15 months of age). Intact and sham-operated cats served as controls. The animals' ability to retrieve chunks of meat through a narrow opening was evaluated for 10 trials on 5 consecutive days. Intact and sham-operated cats showed a dominant movement consisting of a sweeping, sequential, forward, lateral, and medial thrust of the paw to envelop or hook the food with the claws. The animals with lesions showed definite changes in both the paw attitude and the number of swipes required to obtain the pieces of meat. Most severely affected were adult-operated and kitten-operated acaudates, where the dominant attitude was a straight, clubfooted movement with a pronated limb that was quite inaccurate, often many centimeters from the meat. Successful retrievals were usually followed by perseverative responding at that site. In neither of these groups was there a significant change in either attitude or accuracy as a function of training. The unilateral acaudates showed many of the same changes, but all improved with training. The adult-operated afrontals were extremely inconsistent in their behavior and showed a random mixture of normal swipes and dysmetric jabs. The kitten-operated afrontals often missed the meat by several centimeters but improved with practice. These data suggest that (a) the caudate nuclei have a role in controlling the attitude and direction of paw movements; (b) specific defects in paw usage may contribute to the deficits in speed of bar pressing that we have reported for acaudates; (c) the slowness in afrontal cats is probably due to inconsistencies and dysmetria; and (d) pre- and/or postlesion experience may have contributed to differences seen between adult- and kitten-operated groups.

Behavioral observations in squirrel monkeys ( Saimiri sciureus) following methylmercury exposure

Squirrel monkeys were exposed to methylmercuric chloride in various doses (0.0, 2.0, 3.0, 4.0 mg/animal or 3.0, 4.5, 6.0 mg/kg) and observed for general behavioral changes, electrophysiological changes, and quantitative changes in a Wisconsin General Test Apparatus (WGTA). Animals receiving high, medium, and low doses (6.0 mg/kg, 4.0 mg/animal, 4.5 mg/kg, and 3.0 mg/animal) showed signs of mercury poisoning including diminished activity, decreased food consumption, increased errors, latency, and duration in the WGTA, motor problems, and blindness. Electroretinograms (ERG) of blind and sighted animals were unimpaired. Severity of mercury poisoning was related to behavioral effects.

Spatial separation and dimensionality of stimuli in children's discrimination learning.

Research has shown that increasing the distance between stimuli interferes with 2choice simultaneous discrimination learning in kindergartners (2, 3 ) . This effect has been demonstrated both for easv and difficult discriminations. where difficultv is m a n i ~ u lated by varying stimulus similarity ( 3 ) . Another variable influencing task difficulty is stimulus dimensionality. Studies of 3to 5-yr.-old children usually have found that 3dimensional (3-D) stimuli are discriminated more easily than two-dimensional (2-D) stimuli; see review ( 1 ) . The present study explored the effects of spatial separation and dimensionality of stimuli on 2-choice size-discrimination learning of 4-yr.-olds. Six girls and six boys each were assigned to one of four conditions: 2-D near, 3-D near, 2-D far or 3-D far. The 2-D and 3-D stimuli, respectively, were two black cardboard squares and two black wooden cubes. The sides of the squares and of the cubes were 5.08 or 6.35 cm. Stimuli were separated by 6.35 cm. in the near condition and by 25.40 cm. in the far condition. They were presented in a modified Wisconsin General Test Apparatus. The subjects were told, I'm going to hide a marble under one of these squares. Your job is to lift the square you think the marble is under. Stimulus position was predetermined by a modified Gellermann order. The large stimulus was correct for half the subjects of each sex in each condition, and the small one was correct for the remaining half. The learning criterion was 10 consecutive correct responses. The subjects' projected responses on the remaining trials (up to number 60) were recorded as correct. Training was terminated after 60 trials if criterion was not reached. A 2 (separation) x 2 (dimensionality) x 2 (sex) analysis of variance based on number of correct responses yielded a significant main effect of separation = 22.41, p < .001). Subjects performed more poorly in the far condition ( M = 42.20) than in the near condition ( M = 55.43). No other significant main effects or interactions were obtained. These results replicate earlier findings (2, 3 ) that increasing the distance between stimuli interferes with young children's learning. The present study found this effect to be equally strong for 2and 3-dimensional stimuli.

Color preference in the gibbon.

Color preference was tested by showing 6 colored objects to one adult gibbon. The subject demonstrated both color and position preferences on a modified Wisconsin General Test Apparatus. The blue object and, during some conditions, responses to the subject's right were most preferred.

Dynamic stimulus display for the WGTA

A description is given of the design and construction of a three-stimulus display to be used in conjunction with a standard Wisconsin General Test Apparatus (WGTA), The display employs planometric stimuli that are presented by rear illumination of transparent images on closed loops of 70-mm photographic film. These stimuli can be set in motion to provide a stimulus dimension distinct from color, shape, pattern, size, and number. The results of a pilot experiment indicate that movement of test stimuli can be a potent stimulus cue in primate learning tasks.

Successive spatial discrimination reversals in the prairie dog.

Six prairie dogs (Cynomys ludovicianus) were given reversal training on a spatial discrimination reversal task in a Wisconsin General Test Apparatus (WGTA). As with many other species, more errors occurred on the first reversal problem than during acquisition of the original discrimination. However, performance improved over training until each S eventually reversed after a single nonreinforced error. Initial findings indicate that prairie dogs perform at high levels in discrimination learning experiments and could be valuable subjects for psychological research.

Interocular transfer of lateral mirror-image discrimination by cats.

Interocular transfer of mirror-image discriminations has been shown to be paradoxical in split-chiasm monkeys tested in a lighted Wisconsin General Test Apparatus (WGTA) with 3-dimensional forms, but veridical in split-chiasm cats tested in a darkened 2-choice discrimination box with transilluminated patterns. In the present study, 8 split-chiasm cats showed veridical interocular transfer of a mirror-image and a non-mirror-image discrimination in a WGTA or a 2-choice discrimination box. On the basis of the testing parameters used, it is argued that the discrepancy in the literature arises from a species difference (having a behavioral rather than a gross neurological basis), and not from differences in behavioral testing apparatus or mode of stimulus presentation.

Device for Study of Communication of Dominance without Physical Contact

Dominance competition between paired rhesus monkeys ( ns = 4) was compared using a standard apparatus, the Wisconsin General Test Apparatus, and a new device called the Parallel Competition Box. The Parallel Competition Box does not allow physical contact between individual Ss during testing as does the Wisconsin General Test Apparatus. Results comparing the Parallel Competition Box and the Wisconsin General Test Apparatus on food incentive competition indicate that physical contact is not necessary for assertion and maintenance of dominance between socialized rhesus monkeys.

An Apparatus for the Automatic Presentation of Object Discriminations to Monkeys

Object discriminations have traditionally been presented to monkeys by hand in the Wisconsin General Test Apparatus. This method is time-consuming and prone to various kinds of experimenter error. It has proved possible to administer object discriminations automatically by using a modification of the Gloster Saro VM 51 vending machine. This machine, which has space for up to 371 objects, moves them on trays by two electric motors, and the control circuits of these are adapted for external operation by relays and modular programming equipment. A series of simple object discriminations or a concurrent (serial) discrimination task can then be given by remote control. The objects are so treated that by touching either of them the animal completes a circuit, enabling the response to be recorded and appropriately reinforced. Learning in the apparatus seems to be about as efficient as in the Wisconsin General Test Apparatus.

A semiautomated Wisconsin General Test Apparatus

A modification of the WGTA is described. It retains those features of the original apparatus which make it efficient. In addition, it provides (1) precise and largely automatic control of trial pacing and stimulus presentation, (2) simultaneous acquisition of data on problem-solving and locomotor activity of the S, (3) rapid change to any one of a wide variety of behavioral situations, and (4) thorough but quick cleaning and disinfection of the monkey cage.