The domestic dog (Canis familiaris) is the oldest domesticated species and a fascinating model to understand the evolution and development of “personality” concepts. This review summarizes the recent progress in personality research in dogs. The first part of the review introduces the process of evolution and domestication in dogs and discusses a few pioneering studies on this topic. This discussion is followed by details on personality measurements, the structure of personality traits, and the issue of temporal consistency of personality in dogs. In the subsequent sections, I discuss the genetic factors and selection pressures that influence personality in dogs, focusing on differences within an individual breed and across breeds. In this review, I suggest that the personality traits of dogs are measurable in terms of reliability and validity and that they have been shaped by a unique and complicated pathway in the context of dog–human interactions. Further scientific understanding of the concepts of personality is necessary and should be studied by incorporating psychological and biological perspectives.

In recent years, cats have become the most common companion animal in Japan. However, social cognitive research on cats has lagged behind that of dogs. This lag is because of factors unique to cats. Their aversion to novel humans and places makes laboratory experiments difficult and their motivation for food is weaker than that of dogs. Many social cognitive studies that used various measures such as conducting experiments in places familiar to cats have recently been published. In this paper, after reviewing the history of feline domestication, I will review cognitive studies on cats that have been published in recent years, the differences in communication between cat–cat interactions and cat–human interactions, and studies on human–cat attachment. Finally, I will discuss future prospects.

Recent molecular analysis and archaeological evidence has led to the conclusion that an ancestor of the domestic cat (Felis silvestris catus) is the African wildcat (Felis silvestris lybica). The relationship of humans with wildcats, followed by their domestication, may have begun approximately 10,000 years ago in Mesopotamia. The cat was thereafter introduced to ancient Egypt where the process of domestication is assumed to have been completed. The cat acquired the characteristic of having no fear of humans so that the two species have long been capable of cohabitation. Another characteristic that the cat acquired in ancient times was a tolerance to living with a large number of other cats. This characteristic has affected the social system and social behaviors of feral cats. They tend to form a feeding group under situations in which food resources are sufficiently clumped so that many cats can feed. Some social behaviors observed among feral group-living African lions but not among solitary-living wildcats are homosexual behavior by the male cats, communal nursing by the female cats, and male parental care to prevent infanticide. Most of these behaviors are likely to evolve in association with high-density living. In the future, the behaviors of the domestic cat will continue to change under consecutive influences by human society.

Domestic horses, along with dogs, have the longest history of cooperating with humans. The roots of modern domestic horses can be traced back to more than 4200 years ago. Domestic horses have assisted humans in many ways ever since. Over the past 15 years, research on the psychology of horses has been growing, especially in understanding the interaction between horses and humans. This paper focuses on the following socio-perceptive abilities of domestic horses: understanding human pointing, recognizing human attentional and knowledge states, social learning from human behaviors, emotional contagion with humans, perception of human emotion from human facial expressions and voices, and long-term memory of human emotions and impressions of humans. Finally, as a perspective on comparative cognitive science research for the symbiosis between horses and humans, we will discuss and propose measures for elucidating the interaction between horses and humans toward mutual understanding and evaluating and improving the welfare of native Japanese horses and retired racehorses and riding horses.

For thousands of years, birds have been domesticated by humans. In this article, the author argues the effects of domestication on the physical structures, cognition, and behavior of certain bird species, especially parrots. The author describes further details of several aspects of domestication. Animals can have sufficient food and a secure environment under domestication; therefore, the cognition and behavior of captive animals may be affected by the condition. Breeders often select individual animals that have a preferable trait. Artificial selection may change the frequency of an existing gene variant in a population, whereas natural and sexual selection may be inhibited under domestication. Artificial selection may unintentionally introduce changes in cognition and behavior to a population as a by-product of the intentional selection of certain other traits. Furthermore, the author discusses that certain interesting behaviors of domesticated animals may not be caused by the domestication itself, but by relationship to humans or by a meeting with human cultures. For example, the author focuses on recent studies reporting responses by birds to the melodies of man-made music.

Dogs are the most common animals used in animal assisted interventions. However, goats, rabbits, and guinea pigs also provide physical, psychological, and social benefits to humans. Dogs are likely to adapt to animal assisted therapy and are suitable for visiting treatment programs with definite purposes in medical facilities because they can respond to excretion control and behavioral training. However, difficulties involved in keeping goats can cause various ripple effects in animal assisted education if they can cope with a situation. Small herbivores such as rabbits and guinea pigs are likely to be useful for animal assisted education with multidimensional purposes in caregiving in classrooms because of their lovely features, characterized as “baby schema,” and mild behavioral traits. Various animal assisted intervention programs can be introduced, depending on the characteristics of an animal species and the environment. Research reports are limited; however, rabbits and guinea pigs, which are commonly used in primary education in Japan, will also be useful for the further development of animal assisted intervention with regard to animal welfare, practice environment, and purpose.