Intentional binding refers to the apparent compression of the temporal interval between voluntary actions and sensory outcomes. Recent studies have shown that the binding effect differs according to the type of action, namely pressing and releasing. In this study, we examined whether the influence of the type of action can be explained by a sensory association between action and outcome. We manipulated the type of visual outcome (stimulus appearance and disappearance) in addition to the type of action (pressing and releasing) and measured the binding effect using the interval estimation task. The results showed that both the action and outcome types influenced interval estimations: intervals were estimated to be shorter for pressing action than for releasing action, and they were estimated to be shorter when the stimulus appeared than when it disappeared. However, no interaction effect was observed between these factors. Bayesian analysis also supported the model without interaction more than the model with interaction. Our findings suggest that the action and outcome types independently contribute to intentional binding.

Positive valence links to one’s upside and dominant hand/side, whereas negative valence is associated with one’s downside and non-dominant hand/side (i.e., space-valence metaphor). Previous studies have indicated that the effect of the vertical-valence metaphor is more salient than that of horizontal-valence metaphor. Furthermore, this difference in saliency may be related to whether the experimental task is related to rapid reaction and reaction time (RT), which reflects processing fluency. The present study empirically examined these hypotheses by conducting RT (Experiment 1) and non-RT (Experiment 2) tasks (i.e., a detection task in which rapid reactions were required and a pointing task, respectively). We found that the effect of the vertical-valence metaphor occurred in the experiments, while the typical impact of the horizontal-valence metaphor was not found in either. Our findings suggest that the effect of the vertical-valence metaphor is salient, whereas the impact of the horizontal-valence metaphor is not robust. Moreover, this difference in saliency was independent of the type of experimental tasks.

Visual perception of stimuli appearing at the front of the head is facilitated during eccentric gaze when the directions of the eyes and the head differ substantially. This indicates that visual attention tends to move toward the front of the head. This study examined whether top-down control for attending to a specific location influences attention during eccentric gaze. We conducted an experiment in which participants identified the target stimulus presented in the peripheral visual field, manipulating the direction of the head (main-task trials). In this experiment, we added some filler task trials where the target stimulus appeared at the location of fixation. To manipulate top-down control of attention, we varied the stimulus size (i.e., filler-task difficulty), assuming that observers would focus more attention on the location of fixation during the difficult filler-task condition. Head direction influenced visual perception in the main-task trials for both levels of filler-task difficulty. Importantly, the effect of head direction was smaller for the difficult filler-task than for the easy filler-task. Therefore, the effect of head direction on visual attention during eccentric gaze is modulated by top-down control of attention.

Healthy participants can adaptively modulate their trajectory height to reduce possible disturbance to the movement when signal dependent noises increase. We aimed to clarify whether such an adaptive trajectory planning ability is preserved in hemiplegia patients, who showed decreased motor skills because of brain injury, and analyzed reaching kinematics with or without a 200 g weight. We hypothesized that patients would adjust their trajectory in simple reaching movements to compensate the lack of motor control accuracy due to their symptoms. The results show that patients’ trajectories with a weight were higher than those without a weight in affected hands. Moreover, in the 200 g weight condition, even higher trajectory was observed in the second block compared to the first block. These results suggest that hemiplegia patients can plan an adaptive trajectory, considering their movement accuracy, task requirements, and increased effects of motor noises due to muscle fatigue. We also replicated the results of the previous study using healthy participants, which are explained by the same mechanism considering motor noises and task requirements.

The present study aimed to investigate whether the laws of isochrony and homothety hold for Japanese characters by measuring handwriting movements using a liquid crystal display tablet. The law of isochrony means that handwriting time is constant regardless of handwriting size. The law of homothety means that the time required for each character is consistent regardless of the overall time required during continuous handwriting. The twenty-two participants made three shapes, four hiragana characters (Japanese phonetic alphabets),and four kanji characters (Chinese characters) on a tablet at various sizes and speeds. Total handwriting time was longer when character size increased for all character types. This result suggests that the law of isochrony does not hold for Japanese character types. When the characters were written sequentially, the partial handwriting time ratio was indefinite and, varied by character. This result suggests that the law of homothety might not hold for some characters. In summary, this study suggests that the spatiotemporal dynamics of handwriting in Japanese differ by character.

Manual responses are often facilitated when the handle direction of a tool is aligned with the response hand in two-choice reaction-time tasks. This effect is discussed in terms of affordance perception, but that is still controversial. If manual responses are promoted by perceived affordance of grasping, the responses would conversely be suppressed when the danger of grasping is perceived. In this study, 36 right-handed university students performed a discrimination task using blades and non-bladed tools on a tablet screen by tapping on the left or right position near the tool with the left or right index finger. The results showed that the responses were not facilitated even when the direction of the handle was aligned with the response hand. The responses were quicker to blades than to non-bladed tools and especially facilitated when the direction of the edge of the blade and the response position coincided. These results do not support the prediction from affordance perception and can be interpreted as a Simon-type spatial compatibility effect caused by the proximity of attention-grabbing blades to response positions.

Sense of agency refers to the subjective feeling of controlling one’s own actions, and through them, the external events. Sense of agency is integral to self-consciousness, and been the subject of numerous studies aimed at uncovering its underlying mechanism. However, the significance of the sense of agency in human behavior remains poorly understood. Is it simply a by-product of action, or does it play a causal role in our behaviors? This review first briefly summarizes the leading theories of the mechanism underlying the sense of agency and then discusses the ways in which it influences human perception and behavior. The sense of agency is not only a subjective feeling experienced during decision-making and action–execution, but also plays a critical role in shaping our perceptions of the outcomes of our actions, directing our attention, and informing our actions. Furthermore, understanding the role of the sense of agency in cognitive systems is essential for the development of techniques that predict human behavior and subject experience and for designing optimal action plans for systems.

The objects we encounter in everyday settings are composed of multicolored surfaces. To utilize the color information of these surfaces, it is necessary to efficiently summarize the color distribution of object surfaces. Studies examining such summarization (averaging) processes have shown that the three attributes of color — hue, saturation, and brightness — are averaged in different manners. Hue can be averaged accurately and approximated by the arithmetic mean on the uniform chromaticity scale diagram. Averaging of saturation exhibits a bias, with the average tending to shift towards a more saturated direction than the colorimetric mean. Furthermore, this bias becomes more pronounced when there is greater variability (noise) in the color distribution. While there is also a bias observed in the averaging of brightness, the underlying processing strategy seems to be adaptively adjusted depending on the task at hand. These summarizing strategies are believed to be acquired to enhance the reliability and certainty of sensory information in noisy natural environments. Identifying the factors that determine these processing strategies remains a challenge for future research.

Studies have recently shown that statistical summaries for a set of objects with various features can be perceived without much effort. This study examines the information processing of summary perception of a group of faces from three perspectives: 1) how accurately the summary information of a group of faces can be extracted when a diversity of ecologically valid faces are used as stimuli, 2) the region that is strongly weighted in the summary information processing of a group of faces, and 3) what form of mental representation is used to represent the summary information of the perceived face group. Finally, we argue that summary information processing of a group of faces with these characteristics is adaptive for humans forming social groups.

Recent research has revealed that the human visual system is capable of comprehending various pieces of information “at a glance.” Simultaneously, humans continuously receive information from the natural and social environments, which undergo constant changes. Thus, humans can identify patterns and regularities not only in a single moment but also in long-term changes. How the visual system estimates the spatiotemporal ensemble, i.e., the summary statistics of information that varies over time and space? Here, we introduce a series of our research findings that demonstrate how the visual system estimate spatiotemporal-statistical properties of the information from the visual events which probabilistically changes in the spatiotemporal domain, focusing on orientation as a representative visual feature.

The world surrounding us possesses temporally and spatially organized structures deriving from various physical laws. By leveraging these spatiotemporal structures of the external environment as prior information, the visual system compensates for uncertain and unreliable sensory information, facilitating efficient and adaptive perceptual processing. The serial dependence in visual perception refers to the phenomenon where the perception of current stimulus is biased toward previously seen stimuli, suggesting that the brain interprets a series of similar events occurring in succession as continuous events with the same origin. In this paper, we introduce our recent research on serial dependence and discuss its individual differences, and discuss how each individual acquires statistical information in the environment and to what extent they can utilize the acquired prior information.

Anthropomorphism, the tendency to interpret non-human animal behavior through a human-like cognitive lens, poses a persistent challenge in the study of animal cognition. A more significant issue, however, lies in the reliance on simplistic and convenient tests as the sole determinants of specific cognitive abilities in the animals being investigated. Despite these tests being burdened with excessive expectations and complex assumptions, researchers often overlook these intricacies without awareness. This paper advocates for a more comprehensive approach to studying animal cognition and discusses mirror self-recognition and metacognitive information-seeking behavior as illustrative examples.

To study the interactions between humans and dogs and between humans and horses, previous research has investigated whether human behaviors can serve as signals to these animals. Hare et al. (2002) found that dogs are more sensitive to human pointing than chimpanzees, which are the species most closely related to humans, and wolves, which are the species most closely related to dogs. Based on these findings, they argued that dogs possess innate cognitive capacities for processing human social cues, particularly pointing behaviors, as a result of domestication. Conversely, other studies have indicated that minor variations in the pointing task between species may introduce confounding factors in the results. Therefore, this paper identifies and discusses four potential pitfalls―misconceptions that may hinder the progress of research―in studies employing the pointing task. It provides an exploration of the intriguing and challenging aspects of cognitive research involving dogs and horses, with a focus on avoiding these pitfalls.

In this paper, I report my efforts to investigate what animals perceive, with a focus on one of my comparative cognitive studies in which my colleagues and I examined whether pigeons would perceive Ebbinghaus–Titchener illusion. The results of the first two experiments were consistent with the previous studies, supporting the hypothesis that pigeons, known for their local precedence of visual information, might perceive a reversed version of Ebbinghaus-Titchener illusion (i.e., the size of the circle surrounded by larger circles is perceived larger than surrounded by smaller circles). However, further investigation in the two subsequent experiments provided a more plausible, non-illusory account for both previous and present results. Hasty acceptances of evidence that appears to align with the hypothesis or prediction can be a “pitfall”, whereas careful investigation with a healthy dose of skepticism to avoid such pitfalls can contribute to studies involving human participants, for whom verbal instructions and introspection are believed to work well, as well studies involving nonhuman animal subjects.

It has long been debated whether and how verbal processing influences our nonverbal processing. Experimental studies in humans have provided evidence that the acquisition and use of verbal labels modulates our perception and cognition of the labeled items. The evidence, however, is somehow controversial, and the underlying mechanisms are still not completely understood. This paper highlights the significance of comparative cognitive studies on this topic. Comparative studies have revealed that nonhuman animals also learn symbolic labels to categorize items. While only a few studies have investigated the effects of their symbol use on non-symbolic cognitive performance, these studies provide new insight into the labeling effect. This review introduces a preliminary study of capuchin monkeys and discuss the potential contribution and limitations of comparative studies.

In multi-attribute-multi-alternative decision-making research, two-attribute-three-alternative tasks are the standard. When two attributes of a particular product category are contrasted and the choice rates are almost equal, adding a new third alternative changes the preference in relation to the original two alternatives. This results in an irrational choice phenomenon, which is common to various decoy effect types. In particular, three decoy effect types, namely the attraction, compromise, and similarity effects, have been the subject of numerous studies. First, this paper presents a time-series analysis of saccades using eye movement measures. It follows with a report of experiments wherein participants’ mental resources were manipulated by a cognitive depletion task and a glucose drink. There is also an account of the findings of an investigation on the relationship between the attraction effect and mental resources by means of EEG N1 amplitudes and choice rates using task-irrelevant auditory probes and the divided attention task. In the area of multialternative decision making, it may be productive to conduct experimental research based on the assumption of the generic multiple resource model.

In this paper, I discuss phenomena called cognitive biases. In general, cognitive biases are often regarded as “errors.” However, I argue that cognitive biases should be a starting point for understanding the rational side of human cognition and this view leads to an essential understanding of human cognition. As a specific example, I discuss the anchoring effect. The anchoring effect is generally understood as an error people show when making numerical estimations. However, I point out that there are few previous findings showing that anchor-biased estimation results in costs and errors. In addition, I argue the possibility that anchor-biased estimation reflects the diversity of human thinking and such estimation can produce rational estimation.

In this symposium, I introduced “the symmetry bias”. The symmetry bias refers to the tendency to perceive “if A, then B” as also true for “if B, then A”. This bias is closely related to cognitive behaviors such as language and inference in humans. However, until now, reports of this bias in non-human animals have been very limited. Thus, based on our recent study which investigated the symmetry bias in human infants and chimpanzees (Imai et al., 2021), I discussed the following points: what leads to this bias in humans, why it is so robust in human cognition, and what is the adaptive significance of this bias.

The present article summarizes an oral presentation provided at the second forum of Japanese Psychonomic Science. We discuss the effects of partial occlusion of face masks on interpersonal communication in terms of perception of facial emotional expressions, person identification, perception of physical attractiveness. We discuss the two-factor model of attractiveness perception of masked faces and the moderate interpolation hypothesis of perception of attractiveness for masked faces.

Most infants, who were born after the COVID-19 pandemic, can only see the unmasked faces of a very limited number of people. To examine the effect of reductions and/or bias of face experience on the development of face processing, this study measured a visual preference for their mothers’ faces in three different sites in Japan (Aichi, Niigata, and Tokyo). Infants aged 5 to 8 months who were born during the COVID-19 pandemic were presented with their mother’s face and an unfamiliar female face simultaneously. We calculated infants’ preference for their mother’s face under two conditions: No-mask and Mask conditions. As a result, infants in Aichi and Niigata significantly preferred their mother’s face in Mask and No-mask conditions. In contrast, infants in Tokyo significantly preferred their mother’s face only in Mask condition. These results suggest that the development of face processing would adapt to a specific social environment of COVID-19 and there would be regional differences.

Wearing a face mask is effective in controlling the spread of infections. However, it has the negative side effect of obscuring the wearer’s facial expressions. This paper introduces studies investigating the effects of wearing a surgical mask and a transparent mask on the perception of facial expressions among Japanese adults and children. The results showed that wearing a surgical mask impaired one’s performance of reading facial expressions. However, this impairment was mitigated when a transparent mask was worn instead of a surgical mask. Transparent masks can be used in various situations that require the use of face masks.

The haptic feedback technology for conveying haptic information to humans is expected to be used in various domains in the future. However, in general, the technology requires physical stimulation of the human body, necessitating specialized equipment for stimulation, including actuators, batteries, and computers, which poses challenges in terms of convenience and cost. On the other hand, an alternative approach has been proposed, which involves providing haptic feedback based on the manipulation of visual stimuli that co-occurs with the user input such as body motion. This approach does not require physical stimulation and it can provide haptic feedback with convenience and low cost. In this paper, I describe this approach based on “pseudo-haptics”. I describe the representative methods based on pseudo-haptics and characteristics of them.