Biology subjects

Minami, T.

Publications and source records attributed to Minami, T..

8 recordsLinked to original sources

bioRxiv2024

Facial expression recognition is modulated by approach-avoidance behavior

Facial expression recognition influences approach-avoidance behaviors, but do approach-avoidance behaviors affect facial expression recognition? We conducted psychophysical experiments to this end, indicating a reverse causal relationship. In a virtual reality space, 3D face stimulus facial expressions varied on seven levels--from happy to angry in Experiments 1 and 3 and from happy to fearful in Experiment 2. Participants were asked to perform according to one of the following conditions in response to the stimulus. Participants 1) approached (one-meter forward), 2) avoided (one-meter backward), 3) were approached by, or 4) were avoided by the 3D model. Then, participants selected facial expressions. Experiment 1 revealed that participants recognized the face as angrier when they avoided it rather than when it avoided them. Experiment 2 showed that participants recognized the face as happy when approaching and fearful when avoiding, irrespective of who acted. Experiment 3 revealed that participants recognized the face as angrier when the face approached them rather than when they approached if both parties were physically close. Accordingly, approach-avoidance behavior changes facial expression recognition, indicating a reverse causal relationship. We posit that unconscious learning rooted in biological instincts creates this connection.

neuroscience↗

bioRxiv2024

Spatial modulation of facial expression: enhanced recognition of faces behind the observer

Our ability to recognize facial expressions is crucial for understanding others emotions1 and facilitating smooth communication2. Numerous studies have explored how we perceive these cues, considering factors such as health3, social signals4 and personality traits5. However, most of this research involves observers facing a monitor and assessing facial stimuli presented directly in front of them. Real-life scenarios offer more diverse spatial dynamics, such as conversing with someone at a table or glancing back at a passerby. Thus, faces behind the observer might trigger heightened recognition, akin to reacting swiftly to a perceived threat. Herein, we demonstrate that facial expression recognition is influenced by spatial relationships, i.e., faces in front of versus behind the observer. Participants judged the expressions of faces appearing in front of or behind them in virtual space. The findings of three experiments reveal an enhanced level of recognition for faces behind the participant. Interestingly, this effect varies with emotional valence; anger is amplified merely by the presence of a face behind the observer, while happiness requires actively turning to the rear for enhancement to occur. These findings suggest a biological instinct for perceiving threats behind us, potentially influencing subsequent actions. Hence, spatial relationships may modulate facial expression recognition.

neuroscience↗

bioRxiv2024

Element accumulation in the tracheal and bronchial cartilages of monkeys

Compositional changes in the tracheal and bronchial cartilages can affect respiratory ventilation and lung function. We aimed to elucidate element accumulation in the tracheal and bronchial cartilages of monkeys and divided it into four sites: tracheal, tracheal bifurcation, left bronchial, and right bronchial cartilages. The elemental content was analyzed using inductively coupled plasma atomic emission spectrometry. The average calcium content was two to three times higher in the tracheal cartilage than in the other three cartilages. The trends of phosphorus and zinc were similar to those of calcium. The average calcium, phosphorus, and zinc contents were the highest in the tracheal cartilage and decreased in the following order: the left bronchial, right bronchial, and tracheal bifurcation cartilages. These findings revealed that differences existed in element accumulation between different sites within the same airway cartilage and that calcium, phosphorus, and zinc accumulation mainly occurred in the tracheal cartilage. A substantial direct correlation was observed between age and calcium content in the tracheal and bronchial cartilages and all such monkeys with high calcium content were > four years of age. These results suggest that calcium accumulation occurs in the tracheal and bronchial cartilages after reaching a certain age. An extremely substantial direct correlation was observed between calcium and phosphorus contents in the tracheal and bronchial cartilages. This finding is similar to the previously published calcium and phosphorus correlations in several other cartilages, suggesting that the calcium and phosphorus contents of cartilage exist in a certain ratio.

zoology↗

bioRxiv2023

Non-contact respiratory measurements of outdoor-housed rhesus macaques (Macaca mulatta) using millimeter-wave radars

Respiration is an invaluable signal that facilitates the real-time observation of physiological dynamics. In recent years, the advancement of non-contact measurement technology has gained momentum in capturing physiological dynamics in natural settings. This technology is anticipated to find utility in healthcare, not only in humans but also in captive animals, to enhance animal welfare. Currently, the predominant non-contact approach for captive animals involves measuring vital signs through subtle variations in skin color. However, this approach is limited when dealing with body regions covered with hair or outdoor environments under fluctuating sunlight. In contrast, millimeter-wave radar systems, which employ millimeter waves that can penetrate animal fur, exhibit minimal susceptibility to sunlight interference. Thus, this method holds promise for non-contact vital measurements in natural and outdoor settings. In this study, we validated a millimeter-wave radar methodology for capturing respiration in outdoor-housed rhesus macaques (Macaca mulatta). The radar was positioned beyond the captive enclosure and maintained at a distance of > 5 m from the target. Millimeter waves were transmitted to the target, and the reflected waves were used to estimate skin surface displacement associated with respiration. The results revealed periodic skin surface displacement, and the estimated respiratory rate was within the reported range of respiratory rates for rhesus macaques. This result suggests the potential applicability of millimeter-wave radar for non-contact respiration monitoring in outdoor-housed macaques. The continued advancement of non-contact vital measurement technology will contribute to the mental and physical monitoring of captive animals to establish comfortable captive environments. Research HighlightsMillimeter-wave radar systems succeeded in the non-contact measurement of respiration in outdoor-housed rhesus macaques from > 5 m. Our results demonstrate the feasibility of radar-based remote monitoring to assess the welfare of zoo-housed animals.

zoology↗

bioRxiv2023

Examining infantile facial features and their influence on caretaking behaviors in free-ranging Japanese macaques (Macaca fuscata)

Facial features of immature individuals play a pivotal role in eliciting caretaking behaviors in humans. It has been posited that non-human animals share particular infantile facial features with humans, which can elicit caregivers attention and caretaking behaviors. Nevertheless, the empirical examination of this hypothesis is extremely limited. In this study, we investigated infantile facial features in Japanese macaques (Macaca fuscata), their developmental processes, and their correlation with caretaking and infant behaviors, based on 470 facial photographs from one free-ranging group. We measured the size of facial parts and evaluated infantile facial features in Japanese macaques with non-contact procedures with the animals. The results indicated that, although some partial species differences were observed, the infantile facial features in Japanese macaques were broadly consistent with those previously observed in humans and great apes. Furthermore, half of the infant subjects displayed non-linear developmental trajectories of infantile faces similar to those suggested in humans. These changes were sex-based, with most females demonstrating a linear trajectory and most males a hump-shaped development in their facial proportions. However, unlike previous studies in humans, infantile faces were not significantly associated with maternal or non-maternal caretaking behaviors, nor were their developmental changes correlated with infant behavioral development. These findings indicate that while many aspects of infantile facial features are shared among particular primates, humans may have evolved a uniquely elevated preference for selecting such features among the primate lineage.

animal behavior and cognition↗

bioRxiv2023

Human behavior and comfort during load carrying to autonomous mobile robot

Interactions between humans and autonomous mobile robots (AMRs) are expected to grow in smart cities to improve logistics operations, such as depositing packages on AMRs for pickup on the street. However, the way that humans walk and pass objects to an AMR when approaching each other remains largely unknown. We conducted two psychophysical experiments to clarify the behavior and comfort of humans when carrying a package and placing it on an AMR for load carrying. Participants were asked to approach a programmed AMR and pass the package in two experiments: 1) changing the stop distance and AMR speed and 2) changing the stop distance and package weight. Motion trackers quantified the participants walking speed and frequency of hesitation to walk. In addition, the subjective heaviness and comfort were recorded through a questionnaire during each trial. The results indicated that the participants speed decreased and hesitation probability increased when the stop distance of the AMR decreased. Nevertheless, the participants felt more comfortable with the close approach, whereas the package weight did not affect their behavior. By contrast, they felt uncomfortable when AMR remained still. These findings suggest that humans regard the AMR approach as load-carrying assistance and not as invading their personal space. To achieve a comfortable interaction in load carrying from humans to AMRs, we suggest that the AMR can closely approach a person without eliciting personal space invasion.

neuroscience↗

bioRxiv2022

Human collision avoidance behavior against autonomous mobile robot

Currently, the probability of pedestrians on the streets of smart cities encountering autonomous mobile robots (AMRs) is increasing. Previous studies have discussed collision avoidance between humans as they cross paths. Their avoidance behavior toward AMRs, however, remains unclear. To address this, we experimentally investigated the avoidance direction a human would choose against an AMR approaching head-on. This experiment included recording human locomotion under such a scenario. Further, an AMR was programmed to approach from various starting points, including directly through the participants (head-on collision). The participants were directed to evade it by moving rightward or leftward, and their paths were tracked. We found that the participants did not strongly prefer either direction, suggesting that the avoidance direction is not solely determined by the participants attributes, such as their adherence to the traffic rules of their region. The probability of rightward evasion when the AMR approached head-on indicated that humans use different avoidance strategies when encountering other humans and obstacles. Moreover, the participants motion analysis revealed that they involuntarily twisted their waists in the avoidance direction before they evaded the AMR. These results suggest that this twist is the most important predictor of the avoidance direction. These findings could be encoded into the programs of AMRs to adapt these vehicles to our locomotory responses more organically.

neuroscience↗

bioRxiv2022

Glossiness perception and its pupillary response

Recent studies have discovered that pupillary response changes depend on cognitive factors, such as subjective brightness caused by optical illusions and luminance. However, it remains unclear how the cognitive factor derived from the glossiness perception of object surfaces affects pupillary response. We investigated the relationship between glossiness perception and pupillary response through a gloss rating experiment that includes recording pupil diameter. For the stimuli, we prepared general object images (original) and randomized images (shuffled) that comprised of the same images with randomized small square regions. The image features were then controlled by matching the luminance histogram. The observers were asked to rate the perceived glossiness of the stimuli presented for 3,000 ms and changes in their pupil diameter were recorded. Consequently, if glossiness of the original images were rated as high, those of the shuffled were rated as low, and vice versa. High-gloss images constricted the pupil size more than the low-gloss ones near the pupillary light reflex. By contrast, the shuffled images dilated the pupil size more than the original image at a relatively later stage. These results suggest that local features comprising specular highlights involve the cognitive factor for pupil constriction, and this process is faster than pupil dilation derived from the inhibition of object recognition.

neuroscience↗