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Empathy is a complex cognitive ability that has been studied in many social animals, including dogs. Previous studies have found that dogs would rescue their distressed owner more quickly than a calm owner and that dogs respond physiologically and behaviorally to the sound of crying strangers. However, no studies have explored the empathetic and emotional contagion capabilities of dogs towards strangers in rescue paradigms. In the present study, a stranger was placed behind a clear door and was told to cry (distress) or hum (neutral). The dogs' door opening, stress behaviors, tone of approach, and physiological responses were measured. Dogs did not open more frequently or more quickly for the stranger in the distressed condition compared to the neutral condition. Additionally, there was no significant difference between the behavioral or physiological indicators of stress across conditions. It was also found that non-openers were reported by owners to have more fear and, in the empathy test, were more aggressive and fearful in their tone of approach. These results suggest that dogs may be less likely to exhibit empathy-like behaviors to unknown humans in an unfamiliar environment and that owners may be necessary to moderate a dog's stress to show empathetic behaviors.

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Testosterone and its metabolites facilitate male-typical social behaviors in sexually experienced animals. The metabolite estradiol acts on estrogen receptors (ERs) within the bed nucleus of the stria terminalis (BNST) to facilitate socio-sexual behaviors. While circulating testosterone does not increase in naïve males, aromatase-expressing neurons within the BNST of naïve males are necessary for sex recognition, suggesting that local estradiol production may be responsible. In the present study, we examined ERɑ-immunoreactive (ir) cell number within the brain of sexually naïve male rats 24 h after an encounter with a novel animal. As expected, males investigated females more than males. Additionally, males that encountered females had fewer ERɑ-ir cells within both anterior and posterior BNST compared to those who encountered a novel male or a non-social control. There were no changes within the AVPV, MPN, or MeA. The decrease in ERɑ-ir cell number within the posterior BNST only occurred in males that encountered estrus females whereas the decrease in the anterior BNST occurred only in males that encountered non-estrus females. Additionally, anogenital investigations were correlated with fewer ERɑ-ir cells in the posterior BNST, while cage sniffing correlated with the number ERɑ-ir cells in the anterior BNST. There were no differences in serum testosterone 45 min or 24 h after the encounter, suggesting changes in ERɑ were due to local changes in estradiol levels. Our results expand upon previous research regarding the role of estradiol within the subregions of the BNST in naïve male rat socio-sexual behavior.

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Dogs have a reputation for empathy toward their owners, which is also supported by some research (e.g., Carballo et al., 2020; Sanford, Burt, & Meyers-Manor, 2018). Many dog owners anecdotally report that dogs comfort them by making visual and/or physical contact when they cry or help them when they are sick. These behaviours provide a good way to assess the capacity for empathy and its physiological correlates in dogs. This study is a replication and extension of Custance and Mayer (2012). We examined whether using laughing as an alternative stimulus to humming produced similar responses to crying. Dogs were tested in their homes while a stranger and owner pretended to cry, laugh, and while the owner and stranger were talking. During each counterbalanced condition, the dog was observed for person-oriented behaviours and simultaneously had their heart rate variability measured. Like Custance and Mayer, dogs showed more behaviours directed toward the person crying, whether the owner or the stranger, than during baseline or laughing conditions. We did not find an effect of laughing on person-oriented behaviours, suggesting that dogs respond to the crying uniquely and not as a novel stimulus. In the condition when the stranger was crying, dogs that showed higher stress responses, as indicated by lower heart rate variability, were most likely to show person-oriented behaviours toward the stranger. This suggests that dogs that experience more distress, through emotional contagion, are more likely to show person-oriented behaviours toward the distressed stranger, indicating a possible mechanism for empathy-like behaviours. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

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Dogs are thought to evaluate humans' emotional states, and attend more to crying people than to humming people. However, it is unclear whether dogs would go beyond focusing attention on humans in need by providing more substantive help to them. This study used a trapped-other paradigm, modified from use in research on rats, to study prosocial helping in dogs. A human trapped behind a door either cried or hummed, and the dog's behavioral and physiological responses (i.e., door opening and heart rate variability) were recorded. Then, dogs participated in an impossible task to evaluate gaze at the owner as a measure of the strength of their relationship with their owner. Dogs in the distress condition opened at the same frequency, but significantly more quickly, than dogs in the control condition. In the distress condition, the dogs that opened showed lower levels of stress and were able to suppress their own distress response, thus enabling them to open the door more quickly. In the control condition, opening was not related to the dog's stress level and may have instead been motivated by curiosity or a desire for social contact. Results from the impossible task suggest that openers in the distress condition may have a stronger bond with their owner than non-openers, while non-openers in the control condition showed a stronger bond than openers, which may further suggest that the trapped-other paradigm is reflective of empathy.

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In an ever-changing world, the ability to track what significant events occur and where and when is beneficial to a variety of animal species. The purpose of the present studies was to assess the presence of this ability to track what-where-when memory in pigeons based both on when during the day the events occurred and how long ago events occurred. In these studies, pigeons were trained to discriminate between two foods that differed in quality (what), making one more "attractive" than the other. The birds were required to alter their choice of keylights (where) to get these differential foods based on the time of day (Experiments 1-2) or how long ago (Experiments 3-5) they were in a session (when). Pigeons were able to correctly choose the key that yielded the "attractive" food using both time of day and how long ago, indicating a what-where-when memory. However, the pigeons failed to transfer this knowledge to a novel situation, showing limited flexibility in use of the learned what-where-when information. These findings suggest that pigeons have abilities to track what-where-when events as do caching birds and other animal species, but perhaps represented in a more rigid manner.

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Cytokine-induced CNS inflammation has been theorized to contribute to cognitive dysfunction in sickness and neurodegenerative disease. We investigated the effects of systemic endotoxin-induced acute immune activation and inflammation on working memory and attention functions in pigeons assessed through two variations of an operant symbolic matching-to-sample (SMTS) task, employing doses of lipopolysaccharide (LPS) sufficient to induce fever. LPS produced moderate impairments in comparison to saline on the SMTS task designed to measure visual vigilance and attention, but the impairments were not as marked as those produced by chlordiazepoxide (CDP) which is known to disrupt attention. In contrast, LPS had no significant effect on short-term working memory performance compared to saline, while scopolamine, a cholinergic antagonist known to disrupt working memory, did impair performance. The results have implications for the cognitive impairments seen in illnesses characterized by chronic cytokine activation (e.g., Alzheimer's disease) as well as illnesses treated with cytokines (e.g., multiple sclerosis) suggesting that some cognitive failures attributed to working memory impairments per se may better be attributed to prior attention impairments.

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