The connection between action and perception

This thesis consists of three main studies that cover complementary aspects of action-to-perception transfer. In the recent decades, cognitive psychology has started a paradigm shift from its traditional approach to put the stimulus first and treat the action as response to a less one-directional view of perception and action. Quite trivially, action influences perception by changing the external world: we move objects, we locomote or we move our sensory organs. More crucially, action also influences perception internally. Study II and III will address this question directly, by studying perceptual effects of action on physically unchanged stimuli. Study I deals with biological motion. I will argue that the perception of biological motion may present a naturalistic example for direct action-to-perception transfer. The cues of animate locomotion are detected rapidly and effortlessly, and allow quick retrieval of detailed information about the actor, as we related to our immense experience with moving our own bodies in ways that correspond to the physical “laws” which the dynamics of these cues represent. In sum, the studies reported in this thesis provide novel insight on shared action-perception representations, their perceptual consequences and their relation to cognitive models of the world. In Study I, we showed that biological motion cues distort the perceived size of the actor’s figure: a biological motion stimulus is perceived larger than matched control stimuli and lets subsequent stimuli appear smaller. Provided the importance of biological motion, this is in line with other studies that relate subjective importance to perceived size – however, the connection with animate motion has not been reported earlier. If there are shared action-perception representations, do they operate on different representational levels? In Study II, we coupled a stimulus that was in competition with another to action more or less strongly. While the degree of action-perception coupling did not affect overt reports of stimulus’ visibility, oculomotor measures were modulated. This suggests different degrees of action perception coupling on different representational levels, with varying access to awareness. Does in turn the internal cognitive model of the world penetrate action perception coupling? In Study III, we showed that the effect of action-perception congruency on perceptual stability critically depends on the internal cognitive model of action perception coupling. Studies II and III together indicate that no single mechanism or representation can account for all action-perception findings. In the general discussion, I will consider the needed adjustments to current models as well as alternative theoretical approaches

Incidental and Non-Incidental Processing of Biological Motion: Orientation, Attention and Life Detection

Abstract Based on the unique traits of biological motion perception, the existence of a "life detector", a special sensitivity to perceiving motion patterns typical for animals, seems to be plausibl

Medial longitudinal arch development of school children : The College of Podiatry Annual Conference 2015: meeting abstracts

Background Foot structure is often classified into flat foot, neutral and high arch type based on the variability of the Medial Longitudinal Arch (MLA). To date, the literature provided contrasting evidence on the age when MLA development stabilises in children. The influence of footwear on MLA development is also unknown. Aim This study aims to (i) clarify whether the MLA is still changing in children from age 7 to 9 years old and (ii) explore the relationship between footwear usage and MLA development, using a longitudinal approach. Methods We evaluated the MLA of 111 healthy school children [age = 6.9 (0.3) years] using three parameters [arch index (AI), midfoot peak pressure (PP) and maximum force (MF: % of body weight)] extracted from dynamic foot loading measurements at baseline, 10-month and 22-month follow-up. Information on the type of footwear worn was collected using survey question. Linear mixed modelling was used to test for differences in the MLA over time. Results Insignificant changes in all MLA parameters were observed over time [AI: P = .15; PP: P = .84; MF: P = .91]. When gender was considered, the AI of boys decreased with age [P = .02]. Boys also displayed a flatter MLA than girls at age 6.9 years [AI: mean difference = 0.02 (0.01, 0.04); P = .02]. At baseline, subjects who wore close-toe shoes displayed the lowest MLA overall [AI/PP/MF: P < .05]. Subjects who used slippers when commencing footwear use experienced higher PP than those who wore sandals [mean difference = 31.60 (1.44, 61.75) kPa; post-hoc P = .04]. Discussion and conclusion Our findings suggested that the MLA of children remained stable from 7 to 9 years old, while gender and the type of footwear worn during childhood may influence MLA development. Clinicians may choose to commence therapy when a child presents with painful flexible flat foot at age 7 years, and may discourage younger children from wearing slippers when they commence using footwear

Correspondence: Daylighting: Why infra-red should be explored

(Due to the brevity and nature of the paper, no abstract is provided.

The connection between action and perception

This thesis consists of three main studies that cover complementary aspects of action-to-perception transfer. In the recent decades, cognitive psychology has started a paradigm shift from its traditional approach to put the stimulus first and treat the action as response to a less one-directional view of perception and action. Quite trivially, action influences perception by changing the external world: we move objects, we locomote or we move our sensory organs. More crucially, action also influences perception internally. Study II and III will address this question directly, by studying perceptual effects of action on physically unchanged stimuli. Study I deals with biological motion. I will argue that the perception of biological motion may present a naturalistic example for direct action-to-perception transfer. The cues of animate locomotion are detected rapidly and effortlessly, and allow quick retrieval of detailed information about the actor, as we related to our immense experience with moving our own bodies in ways that correspond to the physical “laws” which the dynamics of these cues represent. In sum, the studies reported in this thesis provide novel insight on shared action-perception representations, their perceptual consequences and their relation to cognitive models of the world. In Study I, we showed that biological motion cues distort the perceived size of the actor’s figure: a biological motion stimulus is perceived larger than matched control stimuli and lets subsequent stimuli appear smaller. Provided the importance of biological motion, this is in line with other studies that relate subjective importance to perceived size – however, the connection with animate motion has not been reported earlier. If there are shared action-perception representations, do they operate on different representational levels? In Study II, we coupled a stimulus that was in competition with another to action more or less strongly. While the degree of action-perception coupling did not affect overt reports of stimulus’ visibility, oculomotor measures were modulated. This suggests different degrees of action perception coupling on different representational levels, with varying access to awareness. Does in turn the internal cognitive model of the world penetrate action perception coupling? In Study III, we showed that the effect of action-perception congruency on perceptual stability critically depends on the internal cognitive model of action perception coupling. Studies II and III together indicate that no single mechanism or representation can account for all action-perception findings. In the general discussion, I will consider the needed adjustments to current models as well as alternative theoretical approaches

The walker congruency effect and incidental processing of configural and local features in point-light walkers

Two visual flanker experiments investigated the roles of configural and local opponent motion cues on the incidental processing of a point-light walker with diagonally configured limbs. Different flankers were used to determine the extent of interference on the visual processing of a central walker. Flankers (walkers) with diagonally configured limbs lacked the local opponent motion of the feet and hands, but contained configural information. Partially scrambled displays with intact opponent motion of the feet at the bottom of the display lacked configural information. These two conditions resulted in different effects of incidental processing. Configural information, without opponent motion, leads to changes in reaction time across flanker conditions, with no measurable congruency effect, while feet-based opponent motion causes a congruency effect without changes in reaction time across different flanker conditions. Life detection is a function of both sources of information

Cognition modulates action-to-perception transfer in ambiguous perception

Can cognition penetrate action-to-perception transfer? Participants observed a structure-from-motion cylinder of ambiguous rotation direction. Beforehand, they experienced one of two mechanical models: An unambiguous cylinder was connected to a rod by either a belt (cylinder and rod rotating in the same direction) or by gears (both rotating in opposite directions). During ambiguous cylinder presentation, mechanics and rod were invisible, making both conditions visually identical. Observers inferred the rod's direction from their moment-by-moment subjective perceptual interpretation of the ambiguous cylinder. They reported the (hidden) rod's direction by rotating a manipulandum in either the same or the opposite direction. With respect to their effect on perceptual stability, the resulting match/nonmatch between perceived cylinder rotation and manipulandum rotation showed a significant interaction with the cognitive model they had previously been biased with. For the “belt” model, congruency between cylinder perception and manual action is induced by same-direction report. Here, we found that same-direction movement stabilized the perceived motion direction, replicating a known congruency effect. For the “gear” model, congruency between perception and action is—in contrast—induced by opposite-direction report. Here, no effect of perception-action congruency was found: Perceptual congruency and cognitive model nullified each other. Hence, an observer's internal model of a machine's operation guides action-to-perception transfer

Kinematic-based classification of social gestures and grasping by humans and machine learning techniques

The affective motion of humans conveys messages that other humans perceive and understand without conventional linguistic processing. This ability to classify human movement into meaningful gestures or segments plays also a critical role in creating social interaction between humans and robots. In the research presented here, grasping and social gesture recognition by humans and four machine learning techniques (k-Nearest Neighbor, Locality-Sensitive Hashing Forest, Random Forest and Support Vector Machine) is assessed by using human classification data as a reference for evaluating the classification performance of machine learning techniques for thirty hand/arm gestures. The gestures are rated according to the extent of grasping motion on one task and the extent to which the same gestures are perceived as social according to another task. The results indicate that humans clearly rate differently according to the two different tasks. The machine learning techniques provide a similar classification of the actions according to grasping kinematics and social quality. Furthermore, there is a strong association between gesture kinematics and judgments of grasping and the social quality of the hand/arm gestures. Our results support previous research on intention-from-movement understanding that demonstrates the reliance on kinematic information for perceiving the social aspects and intentions in different grasping actions as well as communicative point-light actions. CC BY 4.0Correspondence: Dr. Paul Hemeren, University of Skövde, Skövde, Sweden, [email protected] article is part of the Research Topic Affective Shared Perceptionpublished: 15 October 2021</p