Even without explicit instructions from adults, children learn culture-specific musical scales through exposure to native music. The mechanisms underlying scale learning are not yet fully understood. Based on the bootstrapping learning theory proposed in the fields of language acquisition and perceptual development, we hypothesized that a perceptually salient pitch in each input melody serves as a self-detected teacher signal in musical scale learning. The present theoretical study employed a deep recurrent neural network (DRNN) to examine a question grounded in this hypothesis: which salient pitch can serve as the self-detected teacher signal? The DRNN was trained based on pairs of input melodies and teacher signals. The input melodies were sourced from popular songs, folk songs, and children’s songs of Western mono-musical culture in Experiment 1 and Western-Japanese bi-musical culture in Experiment 2. The teacher signals were manipulated as independent variables to determine which of the following four pitches in each melody best facilitated the DRNN’s learning of musical scales: three perceptually salient pitches (the first, final, and most frequent pitches) in each melody and one control condition, a non-salient pitch (the eighth pitch in each melody). Results showed that the DRNN successfully learned musical scales only when it was trained with the final pitch in each melody. We propose the hypothesis that the final pitch in each melody can serve as the self-detected teacher signal in children’s musical scale learning.

Boundary extension is a memory distortion characterized by the tendency to recall a scene with visual information that extends beyond its actual boundaries. A previous study (Quinn & Intraub, 2007) reported that even young infants show boundary extension. However, that study used only a single set of visual stimuli. To broaden our understanding of boundary extension in infancy, we conducted experiments with a variety of stimulus sets. Experiment 1 examined whether infants aged 7–8 months exhibited boundary extension for naturalistic scene images, which are known to robustly elicit boundary extension in adults (Bainbridge & Baker, 2020). The results indicated that the infants did not demonstrate boundary extension. Experiments 2 and 3 utilized a stimulus set similar to that employed by Quinn and Intraub (2007). The results showed significant evidence of boundary extension, thus replicating previous findings. In conclusion, infants aged 7–8 months exhibited boundary extension for a specific type of stimulus. Therefore, infants’ boundary extension does not resemble that of adults.

Maintaining appropriate interpersonal space is crucial for communication. Individuals with autism or social anxiety traits are known to perceive interpersonal space differently from typical individuals. However, most previous studies have examined interpersonal distance in face-to-face positions, and the effects of left–right standing positions remain unclear. The present study investigated how changes in angular standing positions between paired individuals and their personal traits affect their interpersonal impressions in communication. Paired participants performed a group discussion task under various left–right angular standing conditions. After each discussion task, participants assessed task performance and interpersonal impressions using an original questionnaire based on the Intrinsic Motivation Inventory (IMI). Additionally, this study assessed personal social traits using the Autism Spectrum Quotient (AQ) and Liebowitz Social Anxiety Scale (LSAS-J). The results showed that closeness scores, which refer to psychological interpersonal distance, differed depending on left–right standing positions. Furthermore, several impression subscales were modulated by similarity in partners’ AQ and LSAS-J scores. These findings suggest asymmetric interpersonal space, along with autism and social anxiety traits, influence interpersonal impressions during communication.

In Japan, formal writing instruction begins after school entry, but children typically start writing in toddlers. As a result, the way children hold writing utensils varies, making instruction at the elementary school challenging. This study compared the pencils with different shaft shapes and lead hardness, as well as felt-tip pens to determine which writing utensils are easier to hold, allows writing with appropriate pressure, and produce correct stroke patterns based on a sample. The results showed that grasping style did not significantly change based on the writing utensil used. Using pencils with softer leads than those employed in previous studies resulted in increased writing pressure. This finding did not align with prior research indicating that writing pressure decreases with the use of softer-lead pencil; instead, it increased. Soft-core pencils did not improve writing accuracy, even for simple characters. The shape of the pencil had no significant effect on grasp, writing pressure, or accuracy. Thus, it is impractical to correct grasp and writing pressure by modifying everyday writing utensils.

This study aimed to determine whether the visual processing of robots differed with age. The Posner task was administered to adults and preschool children aged four and six years, and their gaze responses were recorded. In Experiment 1, the Living and Artefact categories were compared, and the detection time, duration of total fixation, and duration of first fixation were analysed. Both adults and preschoolers showed a category effect in the duration of the first fixation, indicating that the processing of living objects may be faster than that of artificial objects. In Experiment 2, when comparing the Living, Artefact, and Robot categories, a difference in the duration of the first fixation was observed between the Living and Robot categories only for preschoolers. These results suggest that robots’ processing may differ between adults and preschoolers. For adults, robots may be processed based on a process similar to that of other categories. For preschoolers, the processing load for robots may be higher than that for living objects, which may be owing to the underdevelopment of knowledge regarding robots.

In recent years, there has been a growing body of research attempting to account for the perceptual and behavioral particularities observed in individuals with Autism Spectrum Disorders (ASD) through the frameworks of Bayesian inference and predictive coding. According to predictive coding theory, perception arises from the integration of sensory input and prior knowledge. A central computational challenge lies in minimizing the discrepancy—referred to as prediction error—between top-down predictions and bottom-up sensory signals via iterative updates of an internal generative model. It has been hypothesized that, in ASD, atypicalities may arise from disruptions in the processing of precision within this inferential mechanism. This paper provides an overview of predictive coding theory, explores its application to ASD, and examines its relevance to developmental processes. Although reviews of existing empirical studies have yet to yield definitive conclusions, continued investigation may establish predictive coding as a promising theoretical framework for advancing our understanding of human cognition and existence.

Previous research has shown that people taste food better when they are in front of a mirror that reflects themselves. Here, we demonstrate that similar results were obtained when drinking cold tea (Experiment 1) and hot coffee (Experiment 2). The taste of each drink was rated higher in front of a mirror than in front of nonreflecting objects. The ratings for the taste of the hot coffee were also higher when drinking with another person (Experiment 3). Furthermore, the aroma of each drink was rated higher in front of a mirror and when drinking with another person. These results suggest that facilitation effects for aroma and flavor of beverages are efficiently produced by observing visual information that reflects participants drinking beverages as if they were socially facilitated.

To compare the relative importance of contour information—defined solely by the long-short relationship between consecutive tones—and durational ratio information—the ratio of the tone’s durations—in the perception of simple three-tone rhythms, we conducted an immediate recognition task. A standard stimulus was created with a short middle tone between two longer, equal-duration context tones. Recognition was then tested using comparison stimuli in which the middle tone’s duration was systematically varied. We hypothesized that if contour information plays a decisive role, a comparison stimulus would be judged as different only when the middle tone’s duration matched or exceeded that of the context tones. However, our results showed that with long context tones, discrimination accuracy approached its maximum even before the contour pattern changed. This finding indicates that listeners can reliably distinguish rhythms based on durational ratio patterns, even when the overall contour remains constant. Furthermore, shifts in discrimination thresholds as a function of the durational ratio between context and middle tones suggest that duration perception is biased toward simple integer ratios (e.g., 1 : 2 or 1 : 3) in simple three-tone rhythmic patterns.

Illusions are powerful instruments for probing the mysteries of human perception and for disentangling its underlying mechanisms. Many researchers in basic psychology employ visual illusions both as experimental stimuli and in educational/public demonstrations. Yet, while using or viewing illusions is common, creating them remains comparatively rare—even though the act of making promotes deeper inspections and a more concrete understanding of the principles of illusions. This essay presents the aims and experiences of a university course in which novice students learn to program visual illusions and discusses the educational benefits of constructing illusions through programming. I also outline the practical advantages of p5.js—a JavaScript library for visual expression—in rapidly prototyping, visualizing, and iteratively refining illusions. Finally, I frame these activities as outreach in basic psychology and consider how a making-centered approach may cultivate greater interest in and understanding of perception, broadening the societal reach of the discipline.

Over the past 25 years, ensemble perception has been extensively investigated regarding its characteristics and underlying mechanisms. This article begins by clarifying the conceptual and operational definitions of ensemble perception, and then provides an overview of key findings and proposed recent mechanisms using computational models. In particular, this review focuses on ensemble perception of faces in crowds, including stimulus construction, experimental procedures, and major empirical results in this research domain. Given that humans typically function within social groups, ensemble perception of faces enables the extraction of emergent, group-level information that cannot be derived from the perception of individual faces alone. Such information supports adaptive behavior in groups, including the inference of a crowd’s overall emotional state or attentional focus. This review is expected to contribute to the development of integrative theories, applied research, and future empirical advances in this field.

Olfactory perception is experience-dependent and characterized by large inter- and intra-individual variability, making it difficult to obtain consistent perceptual responses. This paper organizes the perceptual characteristics that complicate the design of olfactory experiments and outlines key considerations for experimental planning, implementation, and analysis. Specifically, these include selecting olfactory stimuli and screening participants according to their olfactory experience and level of interest, as well as utilizing verbal labels and learning phases. In addition, controlling visual information and sniffing methods, using reference odors, and employing trained sensory panels can help address inter- and intra-individual variability. Given the inherently low consistency of olfactory perception, olfactory psychology experiments require controls tailored to their specific research objectives.

This report introduces the research area “Face-body design: deepening and sublimating face-body based on practical, empirical and constructive research,” a Grant-in-Aid for Transformative Research Areas (A) for the fiscal years 2025–2029. This project is characterized by its interdisciplinary integration of diverse fields, including not only psychology but also philosophy, cultural anthropology, and robotics. Its primary objective is to construct new theories regarding the future state of the face and body. Interested parties are encouraged to visit the official project website for further information.