A Capuchin monkey (<Emphasis Type="Italic">Cebus apella</Emphasis>) recognizes when people do and do not know the location of food

In a previous study, Kuroshima and colleagues demonstrated that capuchin monkeys (Cebus apella) learned to discriminate between a "knower" who inspected a box for food, and a "guesser" who did not. The aim of the present study was to specify whether the subjects learned a simple conditional discrimination or a causal relationship that seeing leads to knowing. In experiment 1, we introduced five types of novel containers to two subjects. Each container was of different shape and color. The subjects gradually learned to reach toward the container the knower suggested. In experiment 2, we diversified the behavior of the knower and the guesser. In experiment 3, in order to eliminate the possibility of discrimination based on differences in the magnitude and the complexity of two trainers, we equated their behaviors. One subject adapted to the novel behaviors of the knower and the guesser, successfully discriminating the two trainers. Thus this monkey clearly learned to use the inspecting action of the knower and the non-inspecting action of the guesser as a discriminative cue to recognize the baited container. This result suggests that one capuchin monkey learned to recognize the relationship between seeing and knowing.     

关于健康观认知构造的中日比较研究

本研究的目的是揭示大学生关于健康观的认知构造,并对中日大学生健康观的认知构造进行比较。通过对收集到的日常生活的健康观数据进行处理,制成了一个包含50个项目的问卷,然后对收集到的儿8名日本大学生和81名中国大学生的数据进行了因子分析,得到了健康观认知构造的五个因子,即“自律性”(因子Ⅰ)、“主观自我”(因子Ⅱ)、“身体因素”(因子Ⅲ)、“心理因素”(因子Ⅳ)、“健康习惯”(因子Ⅴ)。中日学生的健康观认知结构在Ⅰ、Ⅲ、Ⅳ因子上存在差异。     

Dogs recall their owner's face upon hearing the owner's voice

We tested whether dogs have a cross-modal representation of human individuals. We presented domestic dogs with a photo of either the owner's or a stranger's face on the LCD monitor after playing back a voice of one of those persons. A voice and a face matched in half of the trials (Congruent condition) and mismatched in the other half (Incongruent condition). If our subjects activate visual images of the voice, their expectation would be contradicted in Incongruent condition. It would result in the subjects’ longer looking times in Incongruent condition than in Congruent condition. Our subject dogs looked longer at the visual stimulus in Incongruent condition than in Congruent condition. This suggests that dogs actively generate their internal representation of the owner's face when they hear the owner calling them. This is the first demonstration that nonhuman animals do not merely associate auditory and visual stimuli but also actively generate a visual image from auditory information. Furthermore, our subject also looked at the visual stimulus longer in Incongruent condition in which the owner's face followed an unfamiliar person's voice than in Congruent condition in which the owner's face followed the owner's voice. Generating a particular visual image in response to an unfamiliar voice should be difficult, and any expected images from the voice ought to be more obscure or less well defined than that of the owners. However, our subjects looked longer at the owner's face in Incongruent condition than in Congruent condition. This may indicate that dogs may have predicted that it should not be the owner when they heard the unfamiliar person's voice.     

Chimpanzees (Pan troglodytes) detect strange body parts: an eye-tracking study

Animal Cognition - This study investigated chimpanzee body representation by testing whether chimpanzees detect strangeness in body parts. We tested six chimpanzees with edited chimpanzee body...     

Reverse-reward learning in squirrel monkeys (Saimiri sciureus): retesting after 5 years, and assessment on qualitative transfer

Seven squirrel monkeys (Saimiri sciureus) previously trained on reverse-reward tasks were presented with the original "1-versus-4" task after a 5-year interval without reverse-reward experience (Experiment 1). None of them reliably selected the smaller food array; however, at around chance level, their performance was superior to when they were first exposed to the task almost 6 years previously, suggesting some long-term memory retention. One naive monkey consistently selected the larger array, as expected. In Experiment 2, trials consisting of 1 versus 1 piece of two qualitatively different types of food were interspersed among familiar 1-versus-4 trials. None of five monkeys tested reliably selected the less-preferred food to get the more preferred food as the reward, and one monkey scored below chance. However, when one piece of low-preference food was paired with four pieces of high-preference food (Experiment 3), all four monkeys tested avoided reaching for the latter and thereby obtained it as the reward; two monkeys obtained perfect scores on these trials. These two monkeys were trained on a specific qualitative reverse-reward pairing and then again tested on new pairings (Experiment 4), but transfer was incomplete. Compound trials that pit quantity against quality in novel ways appear taxing for squirrel monkeys, despite competence in reverse-reward on both dimensions separately.     

Plasticity of ability to form cross‐modal representations in infant Japanese macaques

In a previous study, Adachi, Kuwahata, Fujita, Tomonaga & Matsuzawa demonstrated that infant Japanese macaques (Macaca fuscata) form cross‐modal representations of conspecifics but not of humans. However, because the subjects in the experiment were raised in a large social group and had considerably less exposure to humans than to conspecifics, it was an open question whether their lack of cross‐modal representation of humans simply reflected their lower levels of exposure to humans or was caused by some innate restrictions on the ability. To answer the question, we used the same procedure but tested infant Japanese macaques with more extensive experience of humans in daily life. Briefly, we presented monkeys with a photograph of either a monkey or a human face on an LCD monitor after playing a vocalization of one of these two species. The subjects looked at the monitor longer when a voice and a face were mismatched than when they were matched, irrespective of whether the preceding vocalization was a monkey's or a human's. This suggests that once monkeys have extensive experience with humans, they will form a cross‐modal representation of humans as well as of conspecifics.     

Performance of pigeons (Columba livia) on maze problems presented on the LCD screen: in search for preplanning ability in an avian species

The authors examined how pigeons (Columba livia) perform on 2-dimensional maze tasks on the LCD monitor and whether the pigeons preplan the solution before starting to solve the maze. After training 4 pigeons to move a red square (the target) to a blue square (the goal) by pecking, the authors exposed them to a variety of detour tasks having lines as a barrier. A preview phase was introduced, during which the pigeons were not allowed to peck at the monitor. Results of a set of experiments suggest that our pigeons successfully learned to solve these tasks, that they came to take an efficient strategy as the barriers became complex, and that they possibly preplan its solution, at least on familiar, well-practiced tasks.     

Perception of the motion trajectory of objects from moving cast shadows in infant Japanese macaques (Macaca fuscata)

The shadows cast by moving objects enable human adults and infants to infer the motion trajectories of objects. Nonhuman animals must also be able to discriminate between objects and their shadows and infer the spatial layout of objects from cast shadows. However, the evolutionary and comparative developmental origins of sensitivity to cast shadows have not been investigated. In this study, we used a familiarity/novelty preferential looking procedure to assess the ability of infant macaques, aged 7–24 weeks, to discriminate between a ‘depth’ display containing a ball and cast shadow moving diagonally and an ‘up’ display containing a ball with a diagonal trajectory and a shadow with a horizontal trajectory. The infant macaques could discriminate the trajectories of the balls based on the moving shadows. These findings suggest that the ability to perceive the motion trajectory of an object from the moving shadow is common to both humans and macaques.