Automation of learning-set testing: the video-task paradigm

Cognition in the field: comparison of reversal learning performance in captive and wild passerines

Animal cognitive abilities have traditionally been studied in the lab, but studying cognition in nature could provide several benefits including reduced stress and reduced impact on life-history traits. However, it is not yet clear to what extent cognitive abilities can be properly measured in the wild. Here we present the first comparison of the cognitive performance of individuals from the same population, assessed using an identical test, but in contrasting contexts: in the wild vs. in controlled captive conditions. We show that free-ranging great tits (Parus major) perform similarly to deprived, captive birds in a successive spatial reversal-learning task using automated operant devices. In both captive and natural conditions, more than half of birds that contacted the device were able to perform at least one spatial reversal. Moreover, both captive and wild birds showed an improvement of performance over successive reversals, with very similar learning curves observed in both contexts for each reversal. Our results suggest that it is possible to study cognitive abilities of wild animals directly in their natural environment in much the same way that we study captive animals. Such methods open numerous possibilities to study and understand the evolution and ecology of cognition in natural populations.

An autonomous, automated and mobile device to concurrently assess several cognitive functions in group-living non-human primates

Research methods in cognitive neuroscience using non-human primates have undergone notable changes over the last decades. Recently, several research groups have described freely accessible devices equipped with a touchscreen interface. Two characteristics of such systems are of particular interest: some apparatuses include automated identification of subjects, while others are mobile. Here, we designed, tested and validated an experimental system that, for the first time, combine automatization and mobility. Moreover, our system allows autonomous learning and testing of cognitive performance in group-living subjects, including follow-up assessments. The mobile apparatus is designed to be available 24h a day, 7days a week, in a typical confined primate breeding and housing facility. Here we present as proof of concept, the results of two pilot studies. We report that rhesus macaques (Macaca mulatta) learned the tasks rapidly and achieved high-level of stable performance. Approaches of this kind should be developed for future pharmacological and biomedical studies in non-human primates.

Do monkeys choose to choose?

Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task-a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated.

Comparability of developmental cognitive assessments between standard and computer testing methods

Substantial questions have been raised about the validity of using computer-based testing to assess cognitive development with young children. However, little work has been done to assess the comparability of performance elicited using computerized methods with performance garnered using standard testing methods. The purpose of this study was to establish whether computerized testing resulted in performance that was different than established performance norms for infant monkeys (Macaca nemestrina) tested on four highly used cognitive tasks. Infants performed comparably on simple discrimination, reversal learning, and delayed nonmatch to sample rule learning. However, the infants tested in a computer testing-environment appeared to have difficulty on a task that required them to form response strategies. The results of the study reveal some apparent limitations of computer-based testing with infants, but do show that performance on several common cognitive tasks is comparable between the environments.

A computer touch screen system and training procedure for use with primate infants: Results from pigtail monkeys (Macaca nemestrina)

Computerized cognitive and perceptual testing has resulted in many advances towards understanding adult brain-behavior relations across a variety of abilities and species. However, there has been little migration of this technology to the assessment of very young primate subjects. We describe a training procedure and software that was developed to teach infant monkeys to interact with a touch screen computer. Eighteen infant pigtail macaques began training at 90-postnatal days and five began at 180-postnatal days. All animals were trained to reliably touch a stimulus presented on a computer screen and no significant differences were found between the two age groups. The results demonstrate the feasibility of using computers to assess cognitive and perceptual abilities early in development.

Rhesus monkeys (Macaca mulatta) immediately generalize the uncertain response

Rhesus monkeys (Macaca mulatta) have learned, like humans, to use an uncertain response adaptively under test conditions that create uncertainty, suggesting a metacognitive process by which human and nonhuman primates may monitor their confidence and alter their behavior accordingly. In this study, 4 rhesus monkeys generalized their use of the uncertain response, without additional training, to 2 familiar tasks (2-choice discrimination learning and mirror-image matching to sample) that predictably and demonstrably produce uncertainty. The monkeys were significantly less likely to use the uncertain response on trials in which the answer might be known. These results indicate that monkeys, like humans, know when they do not know and that they can learn to use a symbol as a generalized means for indicating their uncertainty.

Computer-assisted enrichment for zoo-housed orangutans (Pongo pygmaeus)

The study of environmental enrichment has identified a variety of effective forms of enrichment, but there are widespread problems associated with their use. Few forms of enrichment are cognitively challenging, and even the most effective often result in rapid habituation. This study examined the use of a computer-joystick system, designed to increase in complexity with learning, as a potential form of enrichment. Eight orangutans (Pongo pygmaeus), housed in male/female pairs, were observed for 120 h during a baseline period and 120h when the computer-joystick apparatus was available. Data were collected in 1 h sessions using instantaneous group scan sampling with 30 s intervals. The orangutans spent 25.9% of the scans using the joystick system. One member of each pair monopolised the computer system: ‘high users’ spent 48.9% of scans using the joystick system compared with 2.9% by ‘low users’. Behavioural changes associated with the provision of the computer included increases in aggressive behaviour, anxiety-related behaviours, solitary play, contact with and proximity to a social partner, and decreases in feeding. The lack of habituation by the high users, both within and across sessions, indicates that computer-assisted tasks may be a useful form of environmental enrichment for orangutans. However, the significant increase in aggression indicates that this form of enrichment may be more suitable for singly caged animals, or that the provision of multiple apparatuses should be tested for the ability to eliminate potential competition over the device.

Increase in reaction time for solving problems during learning-set formation

Six rhesus monkeys were tested for a change in reaction time for problem-solving during a learning-set task, in which they showed progressive improvement in the rate of learning successive problems of visual discrimination. To evaluate the processing time for cognitive processes in problem-solving, the differences in release latency and movement time between the visual discrimination task and the visuomotor control task were defined. In their first experience, the monkeys required several hundreds of trials for solving the problem, and the Deltarelease latency was constant throughout the learning. With increasing experience, they solved problems within fewer trials than with the first problem. At this stage, the Deltarelease latency was high at the beginning and then decreased. The rise in the Deltarelease latency within the learning acquisition period increased depending on the amount of experience with problems they had solved, whereas the Deltamovement time within that period was not significantly affected by the experience with problems. The present findings suggest that the number of problem-solving experiences could promote profound cognitive processing, which may be related to a conceptual representation that actualizes the flexibility of learning, namely, the learning set.

The games psychologists play (and the data they provide)

Computer games and the technologies marketed to support them provide unique resources for psychological research. In contrast to the sterility, simplicity, and artificiality that characterizes many cognitive tests, game-like tasks can be complex, ecologically valid, and even fun. In the present paper,the history of psychological research with video games is reviewed, and several thematic benefits of this paradigm are identified. These benefits, as well as the possible pitfalls of research with computer game technology and game-like tasks, are illustrated with data from comparative and cognitive investigations.

The NASA/LRC Computerized Test System

A new testing package, including apparatus and tasks, is described for the study of behavior of a variety of species in a variety of experiments. The package is described with respect to the kinds of comparative psychological investigations for which it is well suited. The preliminary data generated within this new testing paradigm demonstrate that the NASA/LRC Computerized Test System provides a flexible yet powerful environment for the investigation of behavioral and psychological processes.

PC-compatible computer-generated stimuli for video-task testing

Whereas computer technology allows for the automation of experimentation and data collection, the process of stimulus production has remained a relatively labor-intensive process. A program for automatic computer generation of novel nonverbal stimuli is described in this paper. The program, STIMGEN, allows menu-driven control over the type and appearance of stimuli. Data are presented in which two monkeys matched to sample with high accuracy using stimuli generated with STIMGEN. These data are interpreted to support the usefulness and value of automatic stimulus generation in a variety of applications.

Effects of cognitive challenge on self-directed behaviors by chimpanzees (Pan troglodytes)

In primates, including humans, scratching and other self-directed behaviors (SDBs) have recently been reported to be differentially displayed as a function of social interactions, anxiety-related drugs, and response outcomes during learning tasks. Yet few studies have focused on the factors influencing SDBs in our closest living relatives, the chimpanzees (Pan troglodytes). Furthermore, no previous experimental study has examined handedness of SDBs as a function of changes in task difficulty. Using matching-to-sample tasks of varying difficulty, the present study examines the effect of manipulations of task difficulty on rates, handedness, and type of SDBs in an experimental study of eight chimpanzees. SDBs were categorized as rubs, gentle scratches, and rough scratches. SDBs increased during difficult discriminations, but only for subjects who started the experiment on an easy discrimination; subjects who started on a difficult discrimination exhibited no differential rates of SDBs as a function of task difficulty. There was a tendency to exhibit relatively more SDBs with the right hand in the more difficult task. Rates of SDBs decreased after auditory feedback signals, suggesting a link between SDBs and uncertainty. Rubs were directed more to the face (trigeminal), and gentle and rough scratches more to the body (spinothalamic), suggesting that face-directed SDBs may index a different motivational basis than scratches. Taken together, these results extend previous research on SDBs to the domain of cognitive stress in nonsocial contexts, demonstrating that SDBs are sensitive to manipulations of task difficulty in chimpanzees.

Toward a new outlook on primate learning and behavior: complex learning and emergent processes in comparative perspective

Primate research of the 20th century has established the validity of Darwin's postulation of psychological as well as biological continuity between humans and other primates, notably the great apes. Its data make clear that Descartes' view of animals as unfeeling "beast-machines" is invalid and should be discarded. Traditional behavioristic frameworks--that emphasize the concepts of stimulus, response, and reinforcement and an "empty-organism" psychology--are in need of major revisions. Revised frameworks should incorporate the fact that, in contrast to the lifeless databases of the "hard" sciences, the database of psychology entails properties novel to life and its attendant phenomena. The contributions of research this century, achieved by field and laboratory researchers from around the world, have been substantial--indeed revolutionary. It is time to celebrate the progress of our field, to anticipate its significance, and to emphasize conservation of primates in their natural habitats.

Apparatus as milestones in the history of comparative psychology

Significant apparatus developments from the history of comparative psychology are reviewed, including the contemporary trend toward computer use in research with nonhuman animals. It is argued that milestone apparatus served not only to open new lines of inquiry but also to shape or delimit the nature of the answers that were obtained.

Rhesus monkey (Macaca mulatta) complex learning skills reassessed

Results from three experiments on basic learning and transfer in rhesus monkeys (Macaca mulatta) are reported in which fully automated testing paradigms, afforded by the Language Research Center's Computerized Test System (LRC-CTS), were employed. Performance levels for discrimination learning set, transfer index, and mediational-learning testing were uniformly higher than was predicted from the literature, in contrast to previous reports of compromised learning under similar conditions (automated apparatus, planimetric stimuli, spatial discontiguity between stimuli and response loci). Analyses reveal relatively advanced learning set performance, transfer-index ratios, and positive transfer of learning even at stringent criterion levels. Moreover, the data suggest that rhesus monkeys tested in these experiments exhibit mediational instead of associative learning strategies, as do great apes and in contrast to previous reports of rhesus learning. We argue that the LRC-CTS enhances learning by nonhuman primate subjects, obviating those factors, reported in the literature from experiments in which manual or other automated systems were employed, that compromise learning.