Executive control and task switching in pigeons

Visual Perception Is Highly Flexible and Context Dependent in Young Infants: A Case of Top-Down-Modulated Motion Perception

Top-down modulation is an essential cognitive component in human perception. Despite mounting evidence of top-down perceptual modulation in adults, it is largely unknown whether infants can engage in this cognitive function. Here, we examined top-down modulation of motion perception in 6- to 8-month-old infants (recruited in North America) via their smooth-pursuit eye movements. In four experiments, we demonstrated that infants' perception of motion direction can be flexibly shaped by briefly learned predictive cues when no coherent motion is available. The current findings present a novel insight into infant perception and its development: Infant perceptual systems respond to predictive signals engendered from higher-level learning systems, leading to a flexible and context-dependent modulation of perception. This work also suggests that the infant brain is sophisticated, interconnected, and active when placed in a context in which it can learn and predict.

Executive Functions in Birds

Executive functions comprise of top-down cognitive processes that exert control over information processing, from acquiring information to issuing a behavioral response. These cognitive processes of inhibition, working memory, and cognitive flexibility underpin complex cognitive skills, such as episodic memory and planning, which have been repeatedly investigated in several bird species in recent decades. Until recently, avian executive functions were studied in relatively few bird species but have gained traction in comparative cognitive research following MacLean and colleagues’ large-scale study from 2014. Therefore, in this review paper, the relevant previous findings are collected and organized to facilitate further investigations of these core cognitive processes in birds. This review can assist in integrating findings from avian and mammalian cognitive research and further the current understanding of executive functions’ significance and evolution.

Focusing and shifting attention in pigeon category learning

Adaptively and flexibly modifying one's behavior depending on the current demands of the situation is a hallmark of executive function. Here, we examined whether pigeons could flexibly shift their attention from one set of features that were relevant in one categorization task to another set of features that were relevant in a second categorization task. Critically, members of both sets of features were available on every training trial, thereby requiring that attention be adaptively deployed on a trial-by-trial basis based on contextual information. The pigeons not only learned to correctly categorize the stimuli but, as training progressed, they concentrated their pecks to the training stimuli (a proxy measure for attention) on those features that were relevant in a specific context. The pigeons selectively tracked the features that were relevant in Context 1-but were irrelevant in Context 2-and they selectively tracked the features that were relevant in Context 2-but were irrelevant in Context 1. This adept feature tracking requires disengaging attention from a previously relevant feature and shifting attention to a previously ignored feature on a trial-by-trial basis. Pigeons' adaptive and flexible performance provides strong empirical support for the involvement of focusing and shifting attention under exceptionally challenging training conditions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Selective and distributed attention in human and pigeon category learning

Attention to relevant stimulus features in a categorization task helps to optimize performance. However, the relationship between attention and categorization is not fully understood. For example, even when human adults and young children exhibit comparable categorization behavior, adults tend to attend selectively during learning, whereas young children tend to attend diffusely (Deng & Sloutsky, 2016). Here, we used a comparative approach to investigate the link between attention and categorization in two different species. Given the noteworthy categorization ability of avian species, we compared the attentional profiles of pigeons and human adults. We gave human adults (Experiment 1) and pigeons (Experiment 2) a categorization task that could be learned on the basis of either one deterministic feature (encouraging selective attention) or multiple probabilistic features (encouraging distributed attention). Both humans and pigeons relied on the deterministic feature to categorize the stimuli, albeit humans did so to a much greater degree. Furthermore, computational modeling revealed that most of the adults exhibited maximal selectivity, whereas pigeons tended to distribute their attention among several features. Our findings indicate that human adults focus their attention on deterministic information and filter less predictive information, but pigeons do not. Implications for the underlying brain mechanisms of attention and categorization are discussed.

Feature predictiveness and selective attention in pigeons' categorization learning

Prior categorization studies have shown that pigeons reliably track features that are perfect predictors of category membership (Castro & Wasserman, 2014, 2016a). One might further ask whether pigeons would also track features that are relevant, but imperfect predictors of category membership. In our present project, pigeons had to categorize multiple exemplars from 2 different artificial categories, in which the exemplars were composed of 4 different features that were associated with 1 of 2 different report responses. Each exemplar contained 1 feature that perfectly predicted category membership; 1 feature that imperfectly predicted category membership; and, 2 irrelevant features that did not predict category membership. We monitored pigeons' choice accuracy as well as the location of their pecks to each of the 4 exemplar features to determine to which attributes the birds attended. As categorization accuracy rose, pecks to the perfect predictor of each category rose as well. Pigeons also showed evidence of attending more to the imperfect predictor than to the irrelevant features, but to a lesser degree. Overall, our results provide evidence of selective attention in pigeons' categorization behavior. (PsycINFO Database Record

Task switching in rhesus macaques (Macaca mulatta) and tufted capuchin monkeys (Cebus apella) during computerized categorization tasks

The present experiments extended to monkeys a previously used abstract categorization procedure (Castro & Wasserman, 2016) where pigeons had categorized arrays of clipart icons based upon two task rules: the number of clipart objects in the array or the variability of objects in the array. Experiment 1 replicated Castro and Wasserman by using capuchin monkeys and rhesus monkeys and reported that monkeys' performances were similar to pigeons' in terms of acquisition, pattern of errors, and the absence of switch costs. Furthermore, monkeys' insensitivity to the added irrelevant information suggested that an associative (rather than rule-based) categorization mechanism was dominant. Experiment 2 was conducted to include categorization cue reversals to determine (a) whether the monkeys would quickly adapt to the reversals and inhibit interference from a prereversal task rule (consistent with a rule-based mechanism) and (b) whether the latency to make a response prior to a correct or incorrect outcome was informative about the presence of a cognitive mechanism. The cue reassignment produced profound and long-lasting performance deficits, and a long reacquisition phase suggested the involvement of associative learning processes; however, monkeys also displayed longer latencies to choose prior to correct responses on challenging trials, suggesting the involvement of nonassociative processes. Together these performances suggest a mix of associative and cognitive-control processes governing monkey categorization judgments. (PsycINFO Database Record

Cognitive flexibility and memory in pigeons, human children, and adults

This work examines cognitive flexibility using a comparative approach. Pigeons (Experiment 1), human children (Experiment 2a), and human adults (Experiment 2b) performed a task that required changing responses to the same stimuli twice across the experiment. The results indicate that all three groups demonstrated robust memory for learned information. In addition, pigeons showed comparable and substantial perseveration following both response shifts. In contrast, both children and adults exhibited some perseveration following a first response shift, while exhibiting no cost following the second response shift. These findings are discussed in relation to memory-based theories of cognitive flexibility, according to which perseveration occurs as a result of competition between long-term and working memory, revealing important differences in memory and cognitive flexibility between species.

Non-cortical magnitude coding of space and time by pigeons

Considerable research in cognitive science, neuroscience, and developmental science has revealed that the temporal, spatial, and numerical features of a stimulus can interact with one another [1,2], as when larger stimuli are perceived as lasting longer than smaller stimuli. These findings have inspired the prominent hypothesis that time, space, and number are processed by a 'common magnitude system', which represents these dimensions via the same unit of magnitude [3,4]. According to current theorizing, the parietal cortex mediates this system [4]. To test the species generality and neuroanatomical foundations of this hypothesis, we asked whether space-time interactions can be observed in birds. Unlike mammals, birds lack a cortex [5,6]; rather, they possess a neuron-dense pallium that is organized in clusters, in contrast to the laminar structure of the mammalian cortex [7]. Despite these striking neuroanatomical disparities, we observed reliable space-time interactions in pigeons. Our findings suggest that common magnitude systems are more widespread among animals than previously believed and need not be cortically dependent in all species.