Octopuses, a member of molluscan class, posse well-developed nervous system such as lens eyes that is anatomically similar to our own, and the relative proportion of brain to body is equivalent to vertebrates. Octopuses are also characterized with their muscular highly sensitive sensory receptors, namely, suckers on their arms. Due to these biological uniqueness, octopuses have been a target for psychological studies and were reported their advanced abilities for learning and memory, which are achieved via visual and tactile perceptions. All of these findings have come from experiments that tested single sensory perception (i.e., visual or tactile). On the other hand, it is known in vertebrates that they can integrate multiple sensory information, by which they can vividly image their environments. In this review, we will briefly introduce our knowledge for biology of octopuses with special reference to their cognition, and we will shed light on an idea for cross-modal perception in octopuses, which is based on our on-going projects for visual and tactile learning, and manipulation of arms in tropical octopuses inhabiting the coastal waters of the Ryukyu Archipelago.
With the accumulation of knowledge regarding sociality of animals, social enrichment is regarded as one of the most important part of captive animal care. Although the basic knowledge has been accumulated, sociality involves complex issues. Moreover, practical methodologies for social management remain controversial. In this paper, we overview the current studies and practices of social management on four great ape species (chimpanzees, western lowland gorillas, and Bornean and Sumatran orangutans) housed in Japanese zoos to advance the sociality discussion. We first describe the fundamentals of sociality in animals. Then we explore important topics of sociality, including social relationships in captivity, all male group formation in chimpanzees and gorillas, group living in orangutans, and welfare of disabled and geriatric individuals. Although the number of sociality studies has recently increased, to maximize the positive effects of captive social living, more detailed understanding of the effects of social factors on animals using scientific methodologies is important.
Rhythmic entrainment, or synchronization, to musical rhythm is universally observed in almost all human culture; however, in non-human animals, this kind of behavior has been demonstrated only by some specific species. Thus, exploring the evolutional origin and the psychological substrate for this capability is an attractive research topic. This article reviews recent studies tackling this question and relevant researches, then, introduces a hypothesis explaining the origin of the prominent capability for rhythmic synchronization in humans.
For animals living in groups such as some primates including humans and wolves, it is important to recognize the gaze of others and change their behavior accordingly. Dogs, which have a common ancestor with wolves, gained the ability to read human's gaze even though they are different species in the process of domestication. Although cats are originally solitary animals, cats sharing their living space with humans are frequently observed in modern days. Recent study showed that cats are likely to be able to detect the human gaze directed to themselves. In this study, we examined whether cats are able to recognize the human gaze and whether to change their behavior according to it. We investigated whether cats show different behaviors depending on the direction of the human gaze. As a result, when humans looked at the cats, the time which the cats looked back at the humans was shorter, regardless of familiarity and distance with the humans and the social situation. Also, when humans look at cats when the distance between individuals is short, the eyeblink frequency of cats increases. From these facts, it was shown that cats could recognize directedgaze from humans and change their behavior accordingly.
How should males and females move to get their mating partner? When searchers have no or little locational information of the targets, their movement patterns can determine the search efficiency. In this report, I introduced our recent studies analyzing the efficient movement patterns when both males and females mutually search for mating partners. The extensive simulations revealed the condition where a population with sexually dimorphic movement patterns can achieve the highest individual mating success. The advantage of the dimorphic movement varied across the length of searching time, and it achieved the highest encounter rates at the intermediate time span when encounters of other monomorphic movements were unsuccessful. Moreover, I also proceeded the mate search situation with sex-specific attracting signals and found that signal senders should move more slowly and/or less extensively than receivers to improve mating encounters. These all theoretical predictions were empirically demonstrated by observing mating biology of subterranean termites. Finally, I discussed the advantage of dimorphic movements in a random search which can be applied to various social interactions, including those of our own species.
The saying "A dog (Canis familiaris) is man's best friend" and the term Jinba ittai (describing the connection between a horse ［Equus caballus］ and a human) express the affinitive interactions between humans and these animals. In this paper regarding psychology of learning, these interspecies interactions were considered to indicate that human behaviors change behaviors of these animals and vice versa. Such mutual influence is possible because humans and these animals have innate cognitive systems that allow them to process each other's behaviors, and because humans and these animals learn each other's behaviors. Thus, studies that investigated these cognitive systems and such learning were reviewed. Next, we looked at studies that examined these interspecies interactions during rearing or training. Finally, the reason why humans not only feel that dogs and horses can interact with them but also experience affinitive relationships with these animals was discussed. The innate and learned factors involved in the construction of these relationships were considered.
The field of comparative cognitive science has focused especially on mammals and some birds because of their phylogenetic closeness with humans and their larger brain compared to "lower vertebrates" such as fish. However, recent comparative analyses and conceptual models in the field of animal psychology and/or animal behavior propose that cognitive abilities have evolved in response to ecological and/or social factors. In addition, it has been shown that brain organization are largely conserved throughout the vertebrates, suggesting that lower vertebrates may have more sophisticated cognitive abilities than previously thought. Therefore, to reveal the phylogenetic distribution of cognitive abilities we should also examine lower vertebrates. In fact, ethologists have demonstrated diversity of social and ecological complexities in fish, which are good candidate for helping to reveal how cognitive abilities evolved. Therefore, I focus on fish cognition in this review. Recent studies have shown that some fish behave depending on the types of information they receive. As examples, I introduce studies about flexible decision-making and social cognitive abilities in cichlid fish in Lake Tanganyika, and cleaner wrasse. Finally, I discuss the evolution of cognitive abilities in different ecological contexts.
Bats emit ultrasonic vocalizations through their mouths or nostrils, listen to echoes returning from surrounding objects, and reconstruct three-dimensional images to navigate in the dark. To perform the reconstruction, bats compare their original emission with returning echoes that have been changed by the surroundings. In natural environments, echolocating bats receive various sensory inputs, including insect echoes, clutter echoes, and pulses and echoes from other bats, which must create a complex acoustic situation. Here, we discuss how bats extract own faint echoes in the presence of noise, by focusing on three similar but different situations; auditory masking, clutter interference, and jamming. Sensitivity to faint echoes is maintained after intense pulse emission, by contraction of middle ear muscles during emission. Echoes from off-axis objects could be "defocused" by comparing spectral features in the pulses and echoes. In the presence of conspecifics, bats increase the intensity and duration of pulses to improve the signal-to-noise ratio of their own echoes. They also regulate spectrotemporal features of pulses to separate their own echoes from sounds of conspecifics. Some of the adaptations made by bats may have future engineering applications for radar or sonar systems.
Social intelligence hypotheses propose that complex socialization drives cognitive ability, which animals use to solve the problems associated with complex societies. However, studies of social intelligence have, so far, been limited to a few species, and further studies are needed to discuss "why" social intelligence has evolved in species that have adapted to various environments. Bottlenose dolphins are thought to have complex social systems and cognitive abilities. The evolution of their social intelligence in underwater environments is very different from that of terrestrial animals such as humans and apes. In this paper, we review several social intelligence studies of wild and captive bottlenose dolphins that encompass social interactions ― including affiliative, agonistic interactions and post-conflict affiliations ― and cognitive abilities ― including cooperation, prosocial behavior and joint attention. We also discuss further scope for research on the social intelligence of dolphins.
A sense of body ownership is essential in controlling one's own body in external space, which in turn may give rise to a sense of self-awareness. Body ownership in humans is sometimes extended to certain external objects apart from our own bodies, and such plastic changes in body ownership are thought to be the basis of tool use. Specifically, in a rubber hand illusion task, visuotactile stimuli from synchronous brush strokes to both participants' and rubber hands lead to illusory body ownership of the rubber hand and a shift of perception of the tactile stimuli to the rubber hand as a result of multisensory integration. Recent studies suggest that this kind of body ownership illusion occurs not only in humans but also in animals, including monkeys and mice. In addition, other studies have shown that body ownership is linked to empathy. Studying the body ownership illusion in humans and other animals, including models of human psychiatric disorders, will elucidate neural mechanisms underlying the sense of body ownership, which will consequently contribute to addressing the philosophical issue of self-awareness.
Animal foraging behaviour has evolved in tight association with diverse forms of body structures species-specifically, because morphology shapes and affects perception, information processing, and subsequent motor control. Primates including humans possess skillful sensorimotor control such as tool-using, utilizing their arm-hand morphology. Birds also are capable of dexterous visually-guided behaviors despite the largely different body structures. This rises a question: what and how the body morphology constraints/facilitates behaviors in birds? The present article reviews research advance of sensorimotor control in birds. Specifically, it would be discussed about pecking, the analogous behavior to reaching and grasping in primates and tool-using. The author would suggest a research direction with the morpho-functional and embodiment views for comparative research on sensorimotor mechanisms underlying the dexterous foraging skills.
Until recently, Japanese zoological gardens have primarily been considered as entertainment facilities. However, their roles in wildlife research, education and species conservation are becoming increasingly important. It has been shown that zoo animals exhibit abnormal behaviours and stress responses, which are concerns from both research and animal welfare perspectives. Therefore, attempts have been made to introduce new exhibition or management techniques to ensure that particular behaviours are displayed and to keep the animals occupied. However, the effects of these actions on zoo animals have not been sufficiently verified. In this article, we introduced the research that our team recently conducted at a zoo and will discuss other activities that were carried out at the zoos, ending with suggestions for future research directions.
Birds and primates typically attend to an object of interest using sensitive spots in the retina (i.e. the fovea). Therefore, the direction of their gaze indicates their focus of attention. Recent technological advances in miniature wearable devices allow us to examine birds' gaze behaviors in detail when they are freely moving, and even when they are flying. In this review, I aim to outline current knowledge about how birds use their gaze to attend to an object of interest, and what they are attending to when they are engaging in various natural activities, such as navigation, vigilance, and social interaction. I also aim to outline both strengths and limitations of techniques available for bird gaze-tracking. As a relevant example, I introduce a recent study that utilized Inertial Measurement Unit to examine how pigeons move their gaze while attending to landscapes and flockmates during their homing flights. Overall, I believe that recent sensor technologies offer a promising avenue for examining birds' visual attention and the associated mental processes in natural contexts.
We review use of multiple landmarks in navigational behavior by humans and nonhuman animals focusing on three important aspects of spatial learning and cognition: Cognitive map, spatial integration, and configuration of multiple landmarks. Animals use multiple strategies for spatial navigation rather than a single strategy and flexibly choose an appropriate strategy in accordance with each environmental condition. Concerning the goal searching in humans, for example, whether it is based on information from multiple landmarks or from just one landmark would depend on the salience of the landmarks. Our conclusion is that it is more important what strategies or spatial information animals choose under what conditions than whether or not they have and use the strategies.