The ability to recognise the movements made by humans and other animals, referred to as biological motion, is a specialised human ability that develops at an early age. This perceptual ability is strong even for the minimal amount of information contained in a point-light display, which has been used to study specific features of biological motion to find out what properties contribute to this ability. The perception of biological motion depends on visual perception, visual attention and motor cognition, and perception depends both on the global form, configural information and local information of a body in motion. Depending on the situation, either global or local motions will be more salient and processed to a greater extent by the perceptual system. Previous research has shown that the local and configural information contained in the feet play an important role for identification, direction discrimination and the inversion effect. The salience of the feet for perception has previously been studied when they are subjected to focused attention, but not reflexive attention. The goal of this study was to investigate if the local and configural information of the feet can trigger reflexive attention and be incidentally processed by the visual system in a direction discrimination task. To test this experimentally, a masking paradigm was used where the feet were placed in a mask consisting of scrambled walkers. The results show that the feet affect recognition of target direction when the target is upright, but not when inverted. An interesting and unexpected finding was that for upright targets, the feet aid recognition when they move in the opposite direction of the target. Due to the experimental setup, it is difficult to say with certainty what the results imply, and suggestions for a follow-up study are presented. / Kognitionsvetenskap handlar om hur människor tänker, uppfattar världen och interagerar med omgivningen och med andra människor. Inom kognitiv psykologi har människors förmåga att uppfatta andra människors och djurs rörelser studerats länge. Vi kan känna igen vänner och familj på det unika sätt som de rör sig och forskningen har visat att vi har förmågan att identifiera många olika typer av rörelser och handlingar även när den tillgängliga informationen är minimal. Studier som använt s.k. punktljusdisplayer, där endast vita punkter som representerar kroppens stora leder visas mot en svart bakgrund, har visat att förmågan att känna igen biologiska rörelser är mycket känslig och robust för störningar. Forskare har undersökt vilken information hos rörelser som vi använder för att lyckas med detta, och hur visuell perception och uppmärksamhet fungerar då vi tittar på punktljusdisplayer. Det har visat sig att fötterna har en stor inverkan på igenkänning av rörelseriktning och att det framförallt är på grund av fötterna som det är svårt att känna igen rörelser som presenteras uppochner. Något som inte har testats tidigare är om fötterna är så starka signaler att de kan påverka vår perception även om vi inte riktar fokuserad uppmärksamhet mot dem, utan endast reflexiv uppmärksamhet. Den här studien har testat om fötter kan trigga just reflexiv uppmärksamhet och påverka hur vi känner igen rörelseriktningen hos en gående punktljus-figur. Resultaten visar att fötternas specifika rörelsemönster kan trigga reflexiv uppmärksamhet i situationer då rörelserna är upprätta och då fötterna rör sig i motsatt riktning från den figur som deltagare fokuserar på. Experimentdesignen har dock inneburit att resultaten är svåra att tolka. För att säkrare kunna säga huruvida resultaten beror på fötterna föreslås en ny studie, och detaljer kring vilka justeringar som borde göras i en sådan studie presenteras.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12979号 / 論医博第2105号 / 新制||医||1012(附属図書館) / 32449 / (主査)教授 髙橋 良輔, 教授 佐藤 俊哉, 教授 渡邉 大 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

La perception d’un mouvement biologique correspond à l’aptitude à recueillir des informations (comme par exemple, le type d’activité) issues d’un objet animé en mouvement à partir d’indices visuels restreints. Cette méthode a été élaborée et instaurée par Johansson en 1973, à l’aide de simples points lumineux placés sur des individus, à des endroits stratégiques de leurs articulations. Il a été démontré que la perception, ou reconnaissance, du mouvement biologique joue un rôle déterminant dans des activités cruciales pour la survie et la vie sociale des humains et des primates. Par conséquent, l’étude de l’analyse visuelle de l’action chez l’Homme a retenu l’attention des scientifiques pendant plusieurs décennies. Ces études sont essentiellement axées sur informations cinématiques en provenance de différents mouvements (comme le type d’activité ou les états émotionnels), le rôle moteur dans la perception des actions ainsi que les mécanismes sous-jacents et les substrats neurobiologiques associés. Ces derniers constituent le principal centre d’intérêt de la présente étude, dans laquelle nous proposons un nouveau modèle descriptif de simulation bayésienne avec minimisation du risque. Ce modèle est capable de distinguer la direction d’un ballon à partir d’un mouvement biologique complexe correspondant à un tir de soccer. Ce modèle de simulation est inspiré de précédents modèles, neurophysiologiquement possibles, de la perception du mouvement biologique ainsi que de récentes études. De ce fait, le modèle présenté ici ne s’intéresse qu’à la voie dorsale qui traite les informations visuelles relatives au mouvement, conformément à la théorie des deux voies visuelles. Les stimuli visuels utilisés, quant à eux, proviennent d’une précédente étude psychophysique menée dans notre laboratoire chez des athlètes. En utilisant les données psychophysiques de cette étude antérieure 3 et en ajustant une série de paramètres, le modèle proposé a été capable de simuler la fonction psychométrique ainsi que le temps de réaction moyen mesurés expérimentalement chez les athlètes. Bien qu’il ait été établi que le système visuel intègre de manière optimale l’ensemble des indices visuels pendant le processus de prise de décision, les résultats obtenus sont en lien avec l’hypothèse selon laquelle les indices de mouvement sont plus importants que la forme dynamique dans le traitement des informations relatives au mouvement. Les simulations étant concluantes, le présent modèle permet non seulement de mieux comprendre le sujet en question, mais s’avère également prometteur pour le secteur de l’industrie. Il permettrait, par exemple, de prédire l’impact des distorsions optiques, induites par la conception de verres progressifs, sur la prise de décision chez l’Homme. Mots-clés : Mouvement biologique, Bayésien, Voie dorsale, Modèle de simulation hiérarchique, Fonction psychométrique, Temps de réaction / The ability to recover information (e.g., identity or type of activity) about a moving living object from a sparse input is known as Biological Motion perception. This sparse input has been created and introduced by Johansson in 1973, using only light points placed on an individual's strategic joints. Biological motion perception/recognition proves to play a significant role in activities that are critical to the survival and social life of humans and primates. In this regard, the study of visual analysis of human action had the attention of scientists for decades. These studies are mainly focused on: kinematics information of the different movements (such as type of activity, emotional states), motor role in the perception of actions and underlying mechanisms, and associated neurobiological substrates. The latter being the main focus of the present study, a new descriptive risk-averse Bayesian simulation model, capable of discerning the ball’s direction from a set of complex biological motion soccer-kick stimuli is proposed. Inspired by the previous, neurophysiologically plausible, biological motion perception models and recent studies, the simulation model only represents the dorsal pathway as a motion information processing section of the visual system according to the two-stream theory, while the stimuli used have been obtained from a previous psychophysical study on athletes. Moreover, using the psychophysical data from the same study and tuning a set of parameters, the model could successfully simulate the psychometric function and average reaction time of the athlete participants of the aforementioned study. 5 Although it is established that the visual system optimally integrates all available visual cues in the decision-making process, the results conform to the speculations favouring motion cue importance over dynamic form by only depending on motion information processing. As a functioning simulator, the present simulation model not only introduces some insight into the subject at hand but also shows promise for industry use. For example, predicting the impact of the lens-induced distortions, caused by various lens designs, on human decision-making. Keywords: Biological motion, Bayesian, Dorsal pathway, Hierarchical simulation model, Psychometric function, Reaction time

研究目的：本研究旨在探究高功能自閉症類群障礙（High-Functioning Autism Spectrum Disorder, HFASD）兒童基本的運動知覺、動物生物性運動知覺、與人類生物性運動知覺之偏好注視表現與注意力時間歷程，逐步澄清HFASD兒童的生物性運動知覺表現與社會缺損的關聯性。此外，針對自閉症類群障礙的異質性，進一步探討HFASD兒童具智能優異特質者之生物性運動知覺表現。 研究方法：本研究共招募50名7至10歲之HFASD兒童與25名配對生理年齡與智力之TD兒童。本研究採偏好注視作業，以光點呈現三種運動刺激對比的視覺配對情境：（1）基本運動知覺：物體運動配對散亂運動；（2）動物生物性運動知覺：動物運動配對物體運動；（3）人類生物性運動知覺：人類運動配對動物運動。透過眼動追蹤技術測量受試兒童觀看各運動刺激之凝視時間比例與時間歷程之凝視可能性。研究亦涵蓋智力、症狀嚴重度、及適應行為評估。 研究結果：基本運動知覺方面，TD兒童與HFASD 兒童皆對散亂運動具偏好反應。生物性運動知覺方面，整體來說，TD與HFASD兒童皆較偏好動物與人類運動。時間歷程分析顯示，HFASD與TD兒童在相同的時間窗格對動物與人類運動產生偏好興趣。此外，在動物生物性運動知覺中，於時間歷程早期階段，HFASD兒童偏好動物運動之程度低於TD兒童，且偏好動物運動的程度與社會溝通缺損具相關性，於晚期階段，兩組偏好動物運動的程度無顯著差異。在人類生物性運動知覺中，於時間歷程早期階段，HFASD兒童偏好人類運動的程度與TD兒童相當，隨時間遞增，TD兒童維持對人類運動的偏好興趣，然而，HFASD兒童對人類運動的偏好興趣則逐步遞減，至晚期階段，HFASD兒童偏好人類運動的程度顯著低於TD兒童，且與自閉症狀具相關性。考量本研究HFASD兒童樣本之異質性，結果指出智能優異的HFASD兒童對動物生物性運動的偏好程度與TD兒童相當，但在人類生物性運動知覺中，智能優異組與非智能優異組皆隨時間遞增對人類運動的偏好興趣則逐步遞減。 總結：研究結果指出，HFASD兒童對生物性運動的偏好興趣及產生偏好的速度與TD兒童無明顯差異。但HFASD兒童對人類生物性運動偏好興趣的持續度較TD兒童低落，且不因認知優勢具補償作用。整體而言，顯示HFASD兒童的生物性運動知覺表現型態在反映其社會缺損上具有參考價值。本研究也進一步探討臨床應用、研究限制與未來的研究方向。 / Purposes: This study investigated the preferential attention and attentional processing on the basic motion perception, animal biological motion perception, and human biological motion perception in children with High-Functioning Autism Spectrum Disorder (HFASD). It aimed to explore the processing of biological motion perception in children with HFASD and the association to social deficit. Moreover, concerning the heterogeneity within ASD, the study examined the biological motion perception in intellectually gifted children within HFASD. Method: Fifty children aged 7 to 10 years with HFASD and twenty-five children with typically development（TD）matched on age and IQ were recruited. The current study utilized preferential looking paradigm and motion point-light displays, demonstrating three visual comparison: (1) basic motion perception: object motion paired with scrambled motion; (2) animal biological motion perception: animal motion paired with object motion; (3) human biological motion: human motion paired with animal motion. Eye-tracking techniques were applied to measure proportion of dwell time and time course of fixation probability on each motion stimuli. Cognitive function, symptom severity, and adaptive function were also measured. Result: In basic motion perception, children with TD and HFASD preferentially attend toward scrambled motion. In biological motion perception, generally, children with TD and HFASD preferentially attend toward animal motion and human motion. Time-course analysis revealed that children with TD and HFASD attended toward animal motion and human motion at the same time window. Moreover, in animal biological motion perception, children with HFASD showed lower preferential interest in animal motion than children with TD at the early stage of time course, and there were no significnant difference between groups at the late stage of time course. The results also found that the level of preference for animal motion was associated with the severity of social communication. In human biological motion perception, children with TD and HFASD showed similar level of preferential interest in human motion at the early stage of time course; afterthat, children with TD matained preferential interest in human motion across time, but children with HFASD reduced preferential interest in human motion across time. At the late stage of time course, children with HFASD showed significantly lower level preferential interest in human motion than children with TD, and it was associated to symptom severity. Concerning the heterogeneity within the study sample of HFASD, results indicated that there was no difference on the level of preferential interest in animal motion between intellectually gifted HFASD (IG-HFASD) and TD group; however, in human biological motion perception, IG-HFASD and nonIG-HFASD group reduced preferential interest in human motion across time course compared to TD group. Conclusion: Findings suggested that children with HFASD exhibit the equivalent preferential interest and speed of attending to biological motion as did TD children. However, children with HFASD reduced referential interest in human biological motion across time course compared to TD children, and not influenced by the intellectually gifted advantage with compensation. The results implicated that biological motion perception may play an important role to understanding the social deficit in children with ASD. Theoretical and clinical implications of the study were discussed.