Learning & Behavior最新文献

Evidence has shown significant sex differences in freezing and darting behaviors in a rat model of aversive learning using fear conditioning. The present study explored sex differences in a rat model of aversive learning using a fear-conditioning method via measuring freezing and darting behaviors. Fear conditioning was induced by three footshocks (0.8 mA, 3 s, 30-s interval) paired with an auditory conditioned stimulus (75 dB, 3 s). Extinction was performed by broadcasting 20 auditory conditioned stimuli (75 dB, 3 s, 30-s interval), with no shocks, in three, or four, of five sessions. Freezing and darting behaviors, locomotor activity and time spent in the center squares (anxiety-like behavior) in the open field test, and brain-derived neurotrophic factor (BDNF) in the infralimbic region of the mPFC (medial prefrontal cortex) were evaluated. The results showed both sexes showed a high rate of freezing, with males showing more freezing. Females were more responsive to extinction. Darting behavior was only observed in females and diminished following extinction. Locomotion and anxiety-like behavior were increased and decreased following extinction learning in both sexes, respectively. BDNF expression level in the infralimbic region of the mPFC was increased following extinction learning, with a greater increase in females. In conclusion, we showed that females have a diverse behavioral response to the anticipation of a threat in a rat model of fear conditioning. The important role of BDNF in the modulation of both freezing and darting behaviors was also shown.

Two online experiments investigated whether the weakening of cue-outcome temporal contiguity impacts generalization gradients. Participants experienced strong temporal contiguity (the offset of a cue coincides with the onset an outcome) or weak temporal contiguity (there is a temporal gap between the offset of a cue and the onset of an outcome) in a continuous predictive learning task. Initial training involved a double negative discrimination, in which there was one reinforced cue (aqua-color rectangle) and two non-reinforced cues (one greener and one bluer than the reinforced cue), and participants had to make a response whenever they predicted the outcome. After training, in the generalization test phase, outcome expectancy in the presence of several stimuli along the full green-blue dimension was tested. Outcome expectancy was assessed with discrete ratings in Experiment 1 (n = 252) and a behavioral dependent measure (button presses, similar to the training phase) in Experiment 2 (n = 250). Regardless of the type of measure, when participants experienced weak cue-outcome temporal contiguity they showed a broader generalization response, although differences were more prominent in the green side of the color dimension. Furthermore, no significant differences emerged between the two groups experiencing strong temporal contiguity but differing in cue duration (controlling stimulus onset asynchrony, SOA), suggesting that cue-outcome temporal contiguity plays a more critical role than cue duration in shaping generalization. Overall, this result advances our understanding of the role of temporal contiguity at a basic level, while opening the possibility to study it as a critical factor in more applied settings.

Inhibitory control is an executive function that allows humans and non-human animals to suppress a prepotent response and continue in goal-directed behavior when outcomes are delayed. In non-human animals, inhibitory control has been proposed to be an important component of behavioral flexibility, where animals must inhibit previously used behaviors to establish new ones. The cylinder task has become a widely used, detour-reaching task to test motor response inhibition in many non-human animal species. Here we directly test motor inhibition in raccoons for the first time using a modified version of the cylinder task. Raccoons have demonstrated behavioral flexibility traits such as repeated innovation and reversal learning but have not been tested for motor response inhibition specifically. Five wild-caught, captive raccoons participated in the familiarization and detour procedures of the cylinder task, and we found an overall 60% pass rate in their cylinder task performance. We used k-means clustering to compare raccoons to other species tested in the cylinder task and found that raccoons cluster in the moderate performance group. Raccoons' expression of persistence may lead to their moderate cylinder task performance while benefiting them in tasks related to behavioral flexibility, such as problem solving.

Attention to relevant information is necessary to solve a categorization task. Prior studies monitoring peck location indicated that pigeons narrowly focus their attention on the relevant features of a category exemplar, whereas computational modeling suggested that pigeons' attention can be widely distributed. To help resolve these apparently contradictory results, we deployed both strategies - peck tracking and computational modeling - in the same experiment. Pigeons' peck-tracking scores neatly aligned with their category choices and with the results of the computational modeling. In addition, pigeons displayed distinctive learning and attentional patterns during training and testing. Half of our pigeons showed preferential, even exclusive, use of the most relevant category features, but the other half were inclined to use several of the available features. These results highlight the importance of combining an individual differences approach along with the pursuit of general cognitive principles.

I am honored to have been asked to curate and introduce this special issue recognizing the vast contributions of Dr. Suzanne MacDonald, professor of psychology at York University, Toronto Ontario, Canada, to the field of comparative psychology. As can readily be determined by only a cursory glance at the contents of this special issue, Suzanne's influence has been felt across disciplines as her work encompasses an impressive breadth of species, topics, and contexts. Suzanne is the true embodiment of a comparative psychologist. It is rare that one has impacted so many areas of study and amassed such diversity of experiences, even in a field defined by breadth and comparative analyses. This breadth is reflected in the contributions to this special issue, inspired by the special symposium organized by the Comparative Cognition Society to honor Suzanne at the annual conference in Albuquerque, New Mexico, USA in March of 2025. I am humbled not just by recognition of the quantity of Suzanne's contributions, both in terms of research and service to the field, but also because of the astounding practical significance of her contributions.

One of the computational affordances of isomorphic magnitude representations is the extrapolation of temporal information based on previously experienced spatiotemporal pairings. We initially trained mice on the association of two intervals (10 s and 30 s) with two hoppers (H2 and H4, counterbalanced) in a five-choice nose-poke box with the following setup. One of the three novel hoppers (H1) neighbored H2 only, the other novel hopper (H5) neighbored H4 only, and the third novel hopper (H3) neighbored H2 and H4 (H1_Novel→ H2_Trained→ H3_Novel→ H4_Trained→ H5_Novel). During test trials, one of the five hoppers was illuminated. We estimated the trial time at which the anticipatory response rate was maximal (peak time) separately for each hopper. Mice extrapolated temporal information only in a forward fashion; the peak time for H5 was longer than that for H4. Mice did not extrapolate temporal information backward; the timed response curves in H1 and H3 were closely similar to those in H2. Thus, our findings suggest that mice can extrapolate temporal information, but also indicate that the computations underlying this process are directionally constrained. We discuss the possible reasons behind asymmetrical extrapolation.

Delayed matching-to-position (DMTP) and delayed nonmatching-to-position (DNMTP) tasks are widely used as standard paradigms for evaluating working memory in rodents. In these tasks, which employ a two-alternative forced-choice (2AFC) design, animals initiate each trial by nosepoking a back key, which triggers the illumination of a sample key (either the left or right front key). Upon nosepoking the sample key, a delay begins. During this delay, the back key remains illuminated and animals may nosepoke it, but these responses have no programmed consequence. After the programmed delay, the first nosepoke on the back key activates both front keys. Reinforcement is contingent on choosing the same key as the sample in the DMTP task, or the opposite key in the DNMTP task. Performance is typically measured as the proportion of correct responses across varying delays, which generally decline as delay increases. However, whether the imposed mediating responses used in many protocols effectively prevents the use of nonmnemonic strategies remains insufficiently explored. In this study, we recorded and analyzed the movements of mice during these tasks using automated video tracking. Our findings suggest that mice may rely on nonmnemonic strategies, such as maintaining body position relative to the sample keys, rather than solely on working memory. These results challenge the assumption that DMTP and DNMTP tasks exclusively measure working memory, highlighting the need for cautious interpretation of task performance.

Black-capped chickadees (Poecile atricapillus) are a species of nonmigratory, North American songbird that produce their namesake chick-a-dee call in a wide range of social contexts, including mobbing in the presence of predators. Chickadees produce more D notes per call in response to high-threat predators. Although many studies have examined responses to avian predators, few studies have examined the use of chick-a-dee mobbing calls in response to mammalian predators. Here, wild black-capped chickadees were exposed to avian (sharp-shinned hawk, red-tailed hawk, northern flicker) and mammalian (domestic cat, short-tailed weasel, American red squirrel, woodchuck) mounts of various threat levels, conducted in the field. We investigated production of chick-a-dee calls, number of D notes per call, and feeding in response to predators of varying threat levels. We found that: (1) chick-a-dee call production was significantly larger in response to a high-threat avian predator (sharp-shinned hawk) compared with high-threat mammalian predator (domestic cat); (2) chick-a-dee call D note production did not differ in response to the sharp-shinned hawk compared with the domestic cat mount; but (3) feeding was reduced to the sharp-shinned hawk compared with the domestic cat mount. These findings provide further insight into antipredator responses of black-capped chickadees to both avian and mammalian predators.

Dolphin communication scientists have led the philosophical vanguard of animal translation research since John C. Lilly popularized the idea of human-dolphin communication in the 1960s, and that tradition continues today as multiple teams pursue breakthroughs in understanding cetacean calls using new artificial intelligence tools. But can A.I. resolve the question of meaning-a challenge as elusive today as it was over 60 years ago?

A recent study trained three tool-naïve carrion crows (Corvus corone) to use a stick tool for getting a reward out of a crevice. Automated tracking of tool tips showed gradual changes of their trajectories, demonstrating improved efficiency in their tool dexterity over time (Moll et al. Current Biology, 35, 4845-4852, 2025).