Learning & Behavior最新文献

Behavioral measures of impulsivity and other traits often show weaker test-retest reliability than self-report measures. Weaker reliability impacts the assessment of individual differences in the trait or state being assessed. Behavioral tasks demonstrate greater sensitivity to state variables which may be a key reason for changes in ranked performance across time. The present study examines a single impulsivity task, the escalating interest task, and considers the design principles that may alter the within-session stability of the assessed behavior. A reanalysis of existing data is contrasted with new behavioral data to reveal that rapid changes in task contingencies produced more stable individual differences than prolonged exposure to each contingency. This outcome may be driven by expanding the number of contingencies experienced at each assessment or by keeping behavior in transition. An attempt to avoid floor or ceiling effects by increasing the ambiguity of the contingency, however, did not produce the desired result. The implications of these results for the escalating interest task as well as other behavioral tasks are considered.

The ability to visually recognize objects despite differences in orientation would be advantageous for fish because they see objects from many viewpoints as they navigate their three-dimensional aquatic environment. We tested the ability of goldfish to recognize 3D chromatic and achromatic stimuli from four aspect angles in three rotation planes using a two-alternative forced-choice task. The fish were trained to discriminate between plastic models of a frog and turtle at 0°, then tested with the same objects at 0°, 90°, 180°, and 270°. In Experiments 1 and 2, the stimuli were presented in color, whereas in Experiment 3, the same stimuli were painted black. In Experiment 1, the fish performed significantly better than chance at all aspect angles (0°, ±90°, 180°) and in all three rotation planes. The goldfish displayed viewpoint-invariant performance in the picture plane, but showed enhanced performance at 0° for the two depth plane rotations, which suggests some viewpoint-dependent processes. In Experiment 2, performance accuracy was high regardless of whether the reinforced stimulus (S+) or the non-reinforced stimulus (S-) was rotated in the picture plane. In Experiment 3, two of four fish were successful in recognizing rotated achromatic stimuli. These results, taken together with other studies, suggest that goldfish more easily achieve visual object constancy when the stimuli contain surface features (color, texture, shading).

The study of animal cognition has hosted a long debate about the nature of mental representation. Specifically, whether spatial (map-like) or associative (node-like) models better explain learning and behavior. To explore this, the present experiments tested three pigeons using a novel spatial discrimination task to assess how they learn to discriminate different multidimensional geometric structures. Each trial involved a go/no-go procedure in which a 1.5 cm green target appeared at a random location in an unmarked 15 × 15 cm touchscreen display area. Food reinforcement depended on the target's location. Across experiments, pigeons were tested on discriminations defined by three invisible spatial structures of varying complexity. In the first two experiments, they successfully learned discriminations based on well-formed geometric divisions involving either a vertical or a diagonal discriminative boundary, respectively. In contrast, they failed to learn a mosaic discrimination involving complex, irregular, non-linear divisions of the space. These findings indicate pigeons can learn invisible multidimensional visuospatial discriminations and do so better when the underlying structure is geometrically coherent. Further, this learning appears independent of the discriminative boundary's orientation. The latter matches previous findings testing analogous rule-based (vertical) and information-integration (diagonal) organizations using visual dimensions. It is consistent with the hypothesis that a single non-analytic associative mechanism mediates learning in both cases. Implications for understanding the discriminative representations used by pigeons in solving problems involving fundamental dimensions, like space, are considered.

Motivated behavior is characterized by a high degree of behavioral activation and effort. Preclinical models of operant effort-based decision-making are useful for studying motivational symptoms seen in many psychopathologies as well as observing individual vulnerability. In this study, we evaluated the impact of having alternative reward choices with different effort demands on the decision-making process that may lead to individual differences in working. Adult CD1 male mice, trained on a fixed ratio (FR) 8, were divided into two groups: the no-choice (FR8 for 10% sucrose) and choice (FR8 for 10% sucrose plus concurrent free access to 3% sucrose) conditions. After 5 weeks, a progressive ratio (PROG) schedule was introduced under the same choice conditions. Results indicate that only the no-choice group adjusted their work-output after changing from FR8 to PROG. The choice group did not increase lever pressing when PROG was introduced, but it maintained total fluid intake (10% plus 3%). Water restriction increased intake of all fluids in both choice conditions, independently of the effort required. Additionally, a median split based on PROG performance was used to compare high and low performers. Individual differences in lever pressing were seen under both choice conditions, but only high-performers significantly increased work output when PROG was introduced. Among the choice group, high-PROG performers did not increase total volume obtained compared with low-performers. Thus, the choice condition induced individual differences based mostly on willingness to work rather than to obtain the maximum amount of reinforcer. Further studies in both sexes should characterize this "high-worker" profile.

Cognitive enrichment is essential for improving the welfare of animals in kennels, shelters, and laboratory environments. Whereas touchscreens have been used to engage dogs cognitively, they are limited in functionality. This study tested whether a domestic dog could use a four-button computerized gaming system adapted from the Enclosure Video Enrichment (EVE) system originally designed for sea lions. We trained Orlo, a therapy dog in training, to operate the Canine Experimental Video Enrichment (CEVE) system, which is the first documented instance of a dog engaging with a nontouchscreen gaming interface. Over 11 months, Orlo completed 66 training sessions (~ 21 h), demonstrating steady improvement in both response time and accuracy. He consistently met the button press efficiency criterion (fewer than seven presses per trial) but had longer latencies than sea lions, which trainer observations suggest reflected active engagement rather than misunderstanding. This study provides proof of concept that dogs can operate a four-button interface for gaming; however, the substantial training investment may limit immediate applicability in many shelter or multidog settings. Future research should evaluate strategies to streamline training, incorporate formal welfare measures, expand the sample size to assess breed and individual differences, and determine whether dogs voluntarily engage with the system in the absence of external rewards or in the presence of other enrichment options.

We examined giant panda paw use while feeding on bamboo to determine if this species exhibits manual lateralization. Video recordings of 21 captive giant pandas (15 females and six males) were used to measure two unimanual behaviors: 1) duration of grasping and manipulating bamboo culm during feeding bouts and 2) number of reaches. We did not find paw preferences at the population level but found significant sex differences in paw use. Male giant pandas used their right paw significantly more than their left paw while manipulating bamboo culm, whereas females used their left paw more for both manipulating and reaching for bamboo. Our results differ from previous studies, in which males of most placental quadrupeds have been found to favor the left forelimb more so than females. This preliminary study also suggests that task differences influence the degree of manual lateralization in the giant panda, and challenges the hypothesis that a lack of a corpus callosum leads to sex differences in marsupial forelimb biases. Considering the giant panda's distinctive behavioral ecology, morphology, and evolutionary history, this species provides a valuable model for investigating manual lateralization. We recommend further research on giant pandas, to test our preliminary findings, as well as comparative studies across other ursid species, which exhibit substantial variation in habitat and feeding ecology.

Successive negative contrast (SNC) is a procedure in which animals trained with a large reward consume less of a subsequent smaller reward than animals always trained with the small reward. Studies of SNC in rats have emerged as an important tool in understanding the affective neuroscience of unexpected loss. Establishing a similar procedure in a murine model would allow access to a greater toolbox of neuroscience techniques (e.g., optogenetics, transgenics) that are more readily available in mice than rats. While the rat SNC literature has been thriving for decades, only a few studies report SNC effects in mice. This paper critically reviews the current literature on SNC in mice and presents a failure to replicate SNC using procedures commonly used in rats. Overall, the limited evidence available in mice and a lack of consistent findings suggest that mice may not be the most suitable model for studying the neurobiology of frustration, particularly when compared to the more established rat model.

Cognitive (or behavioral) flexibility is considered an executive function characterized by patterns of behavioral adjustment in response to changes in environmental demands, which tends to decline with aging. The simple discrimination reversal task is a useful way to evaluate this function, as it directly measures processes related to performance change, such as sensitivity to consequences, learning set formation, and concept formation. Few studies on aging have employed this task, and those that have did not examine its component processes or include middle-aged adults. This study aimed to evaluate cognitive flexibility and its component processes through a simple discrimination reversal task, applied to 100 participants divided into four age groups: emerging adults, younger adults, middle-aged adults, and older adults. After learning three simple simultaneous visual discriminations, the function of the positive and negative stimuli was reversed three times, with participants needing to meet a performance criterion each time. Older participants were more likely to fail to meet the performance criterion in some of the reversals, a pattern consistent with reduced sensitivity to consequences and failure in class formation. Moreover, older individuals who succeeded in the task learned the new function assigned to stimuli more slowly during reversals and were less likely to form classes in the second reversal. However, all participants who met the criterion across the three reversals showed evidence of learning-set formation, regardless of age.

Many plant populations are dependent on animal-mediated seed dispersal; however, in the study of mutualistic processes, animals are generally thought of as unselective consumers. This approach is problematic as it does not consider the decisions of the foraging animals, and little attention is given to the cognitive processes that underpin these behaviors. One such process is the ability to predict fruit availability, as this would allow animals to direct their foraging towards productive food sources and would ensure rapid seed removal when fruits are ready to be eaten. This is particularly important for species that cannot move rapidly between resources, such as tortoises. This study investigated temporal (24-h cycle) and visual cues use during food anticipation in captive red-footed tortoise (Chelonoidis carbonaria), an important seed disperser in its natural environment. A significant increase in activity was observed in the hour immediately preceding food delivery, suggesting that the tortoises learned to predict the availability of food. Test trials, in which the visual and temporal cues were put in conflict or removed, revealed that the tortoises used both sources of information to predict food availability. Moreover, extinction trials, in which the tortoises did not have reliable temporal or visual cues prior to feeding, resulted in a rapid loss of anticipatory behavior. These findings provide insights into the cognitive processes that control anticipatory foraging behavior and, as such, have important implications for both animal and plant fitness, furthering our knowledge of mutualistic services such as seed dispersal.

The social facilitation of feeding, where individuals increase their feeding behavior in the presence of conspecifics, is widely documented, but the underlying mechanisms remain unclear, particularly regarding passive versus active facilitation and the role of individual differences, such as sex and personality. We investigated how visual exposure to non-feeding conspecifics influenced feeding behavior in zebrafish (Danio rerio), examining food consumption and other feeding related behaviors, while also assessing individual variation in boldness and sociability. Zebrafish consumed significantly more food pellets and manipulated food differently when conspecifics were present, indicating that passive social facilitation due to the mere presence of conspecifics was sufficient to increase feeding behavior. Males exhibited stronger socially facilitated feeding responses, consuming more pellets, spitting pellets more frequently, and orienting food spitting away from stimulus fish, suggesting competitive motivations. Females showed more cautious feeding behavior, holding pellets in their mouths for longer. Contrary to predictions, neither boldness nor sociability predicted individual differences in feeding behavior or responses to social context. Our findings demonstrate that social facilitation due to a passive audience and sex-specific competitive strategies influence the feeding behaviors of zebrafish.