International Journal of Comparative Psychology

Making an ethogram, a repertoire of the behavior of a species or several related ones, is obviously an important foundation for any theoretical studies of their behavior. In addition, it is useful for conservation, and evolution, and as a basis for good care in captivity. But such a thorough description is neither easy nor quick. This account takes the reader on the author’s journey through lab and field work on seven species and to the struggle to publish results that make up an ethogram of octopuses in the family Octopodidae. 

This addendum reports an additional statistical analysis of the data of our earlier paper on the effect of exposing bees to ethanol vapor. The analysis indicated that inhaled ethanol is absorbed into the hemolymph, similar to the more traditional method of feeding bees ethanol. Therefore, both ingestion and inhalation can be used as effective methods of ethanol administration in honey bees. 

The use of invertebrate models has allowed researchers to examine the mechanisms behind alcoholism and its effects with a cost-effective system. In that respect, the honey bee is an ideal model species to study the effects of ethanol (EtOH) due to the behavioral and physiological similarities of honey bees with humans when alcohol is consumed. Although both ingestion and inhalation methods are used to dose subjects in insect EtOH model systems, there is little literature on the use of the EtOH vapor-exposure method for experiments using honey bees. The experiment presented here provides baseline data for a dose EtOH-hemolymph response curve when using EtOH vapor-inhalation dosing with honey bees (Apis mellifera). Bees were exposed to EtOH vapors for 0, 1, 2.5, or 5 min, and hemolymph was collected 1 min post EtOH exposure. Hemolymph samples were analyzed using gas chromatography (GC) for hemolymph EtOH concentration. The ethanol-hemolymph level of the bees increased linearly with exposure time. The results provide a dosing guide for hemolymph EtOH level in the honey bee model ethanol-inhalation system, and thus makes the honey bee model more robust. 

Animals do not see the external world as it is. Different animals process information in different ways, even when looking at the same object. A visual illusion is a psychological phenomenon by which the eye perceives something as different from what it is. We tested whether a bottlenose dolphin produces the square-diamond illusion to see if it experiences the illusion in the same way as humans. In Experiment 1, two figures (square and diamond) of different sizes were presented in the training session and the subject had to choose the “smaller” figure. In the test session, 22 pairs of squares and diamonds of different areas were presented to see which the subject would choose. When the area difference is large, the percentage of correct responses is high, but when the area difference is small, the percentage of correct responses varies between pairs. When these results were then sorted into “small squares vs. large diamonds” and “small diamonds vs. large squares”, the percentages were significantly high in all pairs in the “small squares vs. large diamonds” group, whereas in the “small diamonds vs. large squares” group, the percentage of correct responses decreased as the difference between the areas of the two figures also decreased. In other words, this result suggests that the illusion may have come into play. Experiment 2 was a square-diamond illusion perception task. Two pairs of squares and diamonds of equal area (225 cm2 and 400 cm2, respectively) were presented and the subject’s choice was then tested. The results showed that the subject chose the square significantly more often than the diamond in both pairs. The square appeared smaller, and the diamond appeared larger to the subject, even though the fact that they had the same area (i.e., it was demonstrated that the square-diamond illusion had occurred), and this study showed that dolphins share the same visual characteristics as humans. 

The common marmoset is a nonhuman primate with a body size similar to an adult rat (approximately 250 – 450 g). This study examined the use of marmosets for behavior research on learning, focusing on the behavioral consequences of audiovisual stimuli (neither food nor liquid used as a reinforcer). A tablet (iPad®) was placed in each marmoset’s individual living cage during the experiment. On the tablet screen, nine small soundless videos of different nonhuman primate species were simultaneously presented. If the marmoset touched any of them, the touched video was zoomed-in on the screen; this was accompanied by the sound of primates chattering as the response consequence. After 2 months of repeated training sessions (10 min/day, 2 or 3 days/week), eight of the ten marmosets established the screen-touch behavior. In an extinction test for the response consequence, the screen-touch response to any of nine primate videos was examined after the presentation of a black screen instead of the above consequence. The number of touch responses decreased compared with baseline control values in three marmosets, whereas responses did not decrease in four marmosets. For the latter marmosets, it was considered that the stimulus changes from the videos to the black screen played a possible reinforcer to maintain the behavior in this test. These findings indicate that the screen-touch behavior, a new learned behavior in the nonhuman primate, could be an operant behavior with an audiovisual response consequence. 

Judgment bias tasks assess optimism and pessimism through responses to ambiguous stimuli. When interacting with ambiguous stimuli, optimistic individuals anticipate receiving a reward whereas pessimistic individuals anticipate a lack of reward, with these differing expectations reflected in approach time. Researchers have used these tests to assess animals’ reactions to assumed positive and negative contexts, but rarely to assess the effects of participation in ambassador programs. We tested two ambassador animals—a domestic chicken (Gallus domesticus) and a red tegu (Salvator rufescens)—after exposure to zoo visitors. Once they learned that a container on the left contained food whereas a container on the right contained no food, we introduced an ambiguous container equidistant from the left and right locations. We assessed the chicken’s judgment biases when she was perched or held. We assessed the tegu’s judgment bias when visitors were allowed to touch him or not. The chicken displayed pessimism whether she was held or perched, but the tegu displayed pessimism only when no visitor touch occurred, suggesting that touch may not be aversive to the tegu, but that interacting with visitors may have deleterious effects on the chicken. We encourage the use of these tests to inform the use of animals in ambassador programs. 

In all organisms, fear conditioning is a behavior that would be expected to be adaptive for anticipating dangerous stimuli.  It therefore should have been selected for in the course of evolution.  Although fear conditioning has been demonstrated in many different species, it had only been shown in one reptile group, lizards, prior to this study.  We developed a paradigm to study fear conditioning in painted turtles (Chrysemys picta).  In each of two experiments, there were three groups: an Experimental group in which a red light (the conditioned stimulus, or CS) was paired with a footshock (the unconditioned stimulus, or US), an Unpaired control group given unpaired presentations of the red light and footshock, and a CS Only control group presented with the red light only.  The experiments differed in the number of days of training: In Experiment 1, the animals were trained for 9 days and were then run on extinction for 6 days.  The results appeared to show that turtles in the Experimental group learned to stop moving when the red light came on, but this was not statistically significant.  There were significant group differences during extinction, however.  It appeared that the behavior was not asymptotic during acquisition, so we ran a second, longer experiment (Experiment 2) for 15 days of acquisition training and 8 or 9 days of extinction.  In this experiment, the Experimental group learned to stop moving during the CS during acquisition and reversed that behavior in extinction. These results demonstrate that classical conditioning with footshock is a suitable method for studying fear learning in turtles.  Further, they shed light on the evolution of fear behavior.  Turtles are closely related to the stem amniotes that gave rise to both mammals and reptiles.  Thus, the results demonstrate that fear conditioning is present in turtles and suggest that it was present in the stem amniote ancestors of mammals as well. 

Several species have demonstrated the ability to cooperate with conspecifics in a lab or zoological setting. The present study sought to replicate previous research (Plotnik et al., 2011) in which pairs of Asian elephants (Elephas maximus) had to simultaneously pull on the ends of a rope in order to bring food rewards within reach. The initial study was conducted in a free-contact setting with Asian elephants, whereas the present study was conducted under a protected-contact management program with ZooTampa at Lowry Park’s herd of six African bush elephants (Loxodonta africana). Trials were deemed successful if the sled was pulled to a distance where both elephants were able to access food that was resting on the sled. Overall, 15 different pairings were tested on the rope-pulling cooperative task while released simultaneously (non-delayed trials). All but one pairing quickly learned that a form of cooperation was necessary to complete the task successfully (p < .05). After non-delayed trials were complete, trials were run with a five-second delay interval for one of the two elephants to assess the elephants’ understanding of the role of a partner in the cooperative task (delayed trials). Four elephants were faced with the decision of waiting for their partner to arrive before pulling their end of the rope, of which two juvenile elephants successfully waited for their partner. This study contributes to the literature of cognition across the elephant taxon. 

The bottlenose dolphin (Tursiops truncatus) vocalizations called “burst pulses” exhibit distinct acoustic properties and can potentially be linked to affective states. This study aimed to determine if dolphins produce burst pulses during match-to-sample with both successful and unsuccessful outcomes and to explore any association with positive affect. We observed that burst pulses occurred in 74% of match-to-sample trials (in which the subject views a sample object and selects the match from a group of alternative objects), with a significantly higher frequency during correct responses. Additionally, there was a notable difference in the proportion of burst pulses occurring before versus after the trainer’s bridge, with more burst pulses occurring before the trainer’s bridge. The timing and characteristics of these burst pulses suggest they may be related to the dolphins’ interest and excitement rather than merely a response to reinforcement. These findings provide new insights into the complexity of dolphin vocalizations and their potential connection to affective states. 

This paper reviews the effectiveness and application of communication buttons as a means of interaction with domestic dogs (Canis familiaris), based on the personal experiences of users. The results showed that dogs are capable of communicating through buttons, expressing their needs, and forming multi-word phrases. The highest success rate was observed in medium and large breeds between the ages of 6 months and 5 years. Nearly half of the dogs learned to use their first button within a week, although button spamming behavior was also observed in some individuals. Statistical analysis revealed that dogs preferred specific word categories (particularly activity/place and reward), although differences in the intensity of usage between categories were not statistically significant due to high variability within groups. The ability to combine words into more complex expressions was observed in approximately half of the dogs. The findings also suggest that independent button use can sometimes lead to less purposeful patterns, such as repeatedly pressing buttons ("spamming"). 

This study aimed to examine whether a lactating Steller sea lion pup (Eumetopias jubatus) could learn the associations between human commands (verbal/ visual) and behavior. A male Steller sea lion pup named Kanata was artificially cared for from the age of 36 hours. When Kanata was three months old, we began behavior-shaping training using milk as a reinforcer. During the training phase, which lasted approximately three months, Kanata learned nine behaviors. The trainers simultaneously presented Kanata with both hand signals and vocal commands to condition each behavior's association with the human commands. In the test phase, we tested the effects of associative learning between the human commands and each behavior in the three conditions. When trainers simultaneously gave him hand signals and vocal commands (Condition 1), Kanata’s performance was significantly higher than for the other conditions (Condition 2: only hand signals and Condition 3: only vocal commands). Additionally, Kanata’s performance was significantly higher in Condition 2 than in Condition 3. Although Kanata’s performance was stable for all commands in both Conditions 1 and 2, it was significantly low for almost all commands in Condition 3. These results provide the first evidence to suggest that a Steller sea lion pup has an excellent ability of associative learning and that he could shape the associations between the human commands and behaviors in both visual and auditory modalities, but his learning association could be dominant in visual information, compared to auditory information. 

The social intelligence hypothesis posits that animals living in more complex social groups display better cognitive performances. However, this hypothesis has mainly been investigated in primates and studies using similar paradigms across different species are scarce. Here, we tested three species of wild Lamprologine shell-dwelling cichlid fishes from Lake Tanganyika (Neolamprologus multifasciatus, Lamprologus ocellatus, and L. ornatipinnis) that vary in their levels of sociality. We developed a standardized learning paradigm well-established in various species, including cichlids. We used shells, with which the fishes inherently interact, to design an ecologically relevant apparatus to test the three species in identical color associative learning and social learning tasks. We found species differences in engagement in the training for these tasks and only 5 out of 24 individuals learnt to feed from a neutral white shell. One L. ocellatus and one L. ornatipinnis learnt to choose the correct colored shell in the associative learning task and were further used as demonstrators in the social learning task. In this task, no species showed signs of color stimulus enhancement as the observers’ choices of colors were not influenced by the demonstrators. However, we found evidence for stimulus enhancement at a larger scale as naïve observers approached the novel experimental apparatus faster than the demonstrators when first exposed to this apparatus. Our results encourage further research of social learning processes in individual fishes and highlights the difficulties in using standardized tests in comparative psychology, even across very close species. 

In social foraging situations, group members choose between two strategies: (a) actively engage in searching for resource sources (Producing); or (b) join a resource source previously discovered by another group member (Scrounging). Two predictions of the Rate-Maximization Model are: (a) the proportion of producers will be lower in conditions where the group size is larger; and (b) the proportion of producers will be lower in conditions where the number of resources is higher. While these predictions have been tested across various species, the number of studies involving human participants remains relatively low. Using an agent-based model approach, we propose a Direct Interaction Task to study the producer-scrounger game in human participants. In this online behavioral task, a single participant moves freely within the habitat and competes for resources against agents. The study involved 80 university students assigned to one of four conditions that varied by group size (G4, G8) and the number of prey (F5, F15). The results show a decrease in the producer index when the group size was larger; however, no effect was observed for the number of prey. This study highlights the potential for investigating social foraging in controlled environments without extensive physical space. 

Shadow boxing is the aggressive response of an animal to its reflection. When the species is strong enough to break surfaces (e.g., bear, monkey, woodpecker), this behaviour can lead to human-wildlife conflicts. In this pilot study, we assessed whether shadow boxing is subject to habituation (learning to ignore stimuli) in Southern ground-hornbills (Bucorvus leadbeateri). In the Mirror task, birds were repeatedly exposed to unbreakable mirrors (habituation). Subsequently, one mirror was presented at a different location (test). In the Neophobia task, a food reward was placed next to novel objects. Ground-hornbills did not habituate to the mirrors, but they differed in their levels of neophobia. 

The present study aimed to investigate whether children could acquire the oddity concept using olfactory stimuli. To this end, three children aged 3 to 6 years were concurrently trained on multiple odor oddity problems and tested with novel ones. The findings showed that the 6-year-old participant mastered the acquisition training and transferred this experience to the novel oddity problems in the transfer test, suggesting that the child had acquired a relational understanding of the difference between odd and identical odor stimuli. Factors influencing the acquisition of the oddity concept were discussed.