Visual Exploration Of Objects Research Articles

Effects of visual and visual-haptic perception of material rigidity on reaching and grasping in the course of development

The development of material property perception for grasping objects is not well explored during early childhood. Therefore, we investigated infants', 3-year-old children's, and adults' unimanual grasping behavior and reaching kinematics for objects of different rigidity using a 3D motion capture system. In Experiment 1, 11-month-old infants and for purposes of comparison adults, and in Experiment 2, 3-year old children were encouraged to lift relatively heavy objects with one of two handles differing in rigidity after visual (Condition 1) and visual-haptic exploration (Condition 2). Experiment 1 revealed that 11-months-olds, after visual object exploration, showed no significant material preference, and thus did not consider the material to facilitate grasping. After visual-haptic object exploration and when grasping the contralateral handles, infants showed an unexpected preference for the soft handles, which were harder to use to lift the object. In contrast, adults generally grasped the rigid handle exploiting their knowledge about efficient and functional grasping in both conditions. Reaching kinematics were barely affected by rigidity, but rather by condition and age. Experiment 2 revealed that 3-year-olds no longer exhibit a preference for grasping soft handles, but still no adult-like preference for rigid handles in both conditions. This suggests that material rigidity plays a minor role in infants' grasping behavior when only visual material information is available. Also, 3-year-olds seem to be on an intermediate level in the development from (1) preferring the pleasant sensation of a soft fabric, to (2) preferring the efficient rigid handle.

Visual exploration of objects and scenes in patients with age-related macular degeneration

Studies on people with age-related macular degeneration (AMD) have shown that they are able to detect briefly displayed objects and scenes with high accuracy (above 80%). However, in everyday life we explore our environment to search and to recognize objects. We assessed visual exploration in people with AMD during the identification of objects and scenes. Twenty patients with AMD, fifteen age-matched and twelve young controls participated. We used colored photographs of isolated objects, natural scenes and objects in scenes, displayed centrally on a monitor. Participants were asked to name the objects and scenes. Ocular movements were recorded during the identification task. Scan paths, saccades, fixations, and accuracy were also recorded. People with AMD exhibited lower accuracy (by about 30%). Eye movement parameters were impaired with a larger number of saccades, shorter fixation durations and a larger scan path than controls. Our results are consistent with studies on artificial scotoma in normally sighted people showing that a central scotoma impairs oculomotricity. In contrast to detection tasks, people with central vision loss exhibit impaired performance in identification of objects and scenes (62 to 66%). Eye movement studies suggest that the lower accuracy in patients is likely due to the use of peripheral vision and instability of fixation.

From Exploration to Fixation: An Integrative View of Yarbus's Vision.

Alfred Lukyanovich Yarbus (1914-1986) pioneered the study of stabilized retinal images, miniature eye movements, and the cognitive influences that act on visual scanning. Yarbus's studies of these different topics have remained fundamentally disconnected and independent of each other, however. In this review, we propose that Yarbus's various research lines are instead deeply and intrinsically interconnected, as are the small eye movements produced during visual fixation and the large-scale scanning patterns associated with visual exploration of objects and scenes. Such apparently disparate viewing behaviors may represent the extremes of a single continuum of oculomotor performance that operates across spatial scales when we search the visual world.

Visual exploration of objects and scenes in people with Stargardt disease and macular degeneration

Visual exploration of objects and scenes in people with Stargardt disease and macular degeneration

The relationship between visual object exploration and action processing in schizophrenia

Introduction. Abnormalities in visual exploration and action processing are widely reported in schizophrenia. The aim of this study was to investigate whether object exploration (in order to recognise an action or the object) modulates visuomotor behaviour differently in schizophrenic patients and controls. Methods. Visual scan paths were monitored in 36 patients and 36 controls. Participants performed three tasks, in which they were asked to either (1) name the object (the object-naming task), (2) picture themselves interacting with the object and then name the action (the action-naming task), or (3) explore the object (the free-viewing task). Results. Patients explored objects less than controls did. Controls explored the part needed to identify an object in the object-naming task and the whole object in the action-naming and free-viewing tasks. In contrast, the patients maintained their gaze on the “identity” part of the object in all three tasks. Conclusion. Our results were consistent with the literature findings on impaired action processing in schizophrenia but also extend the known impairment to implicit action processing when the subject is visually exploring an object. We discuss our results in terms of motivation, the effect of dopamine on eye movement, attentional capture, and frontal lobe dysfunction.

Teach to reach: The effects of active vs. passive reaching experiences on action and perception

Reaching is an important and early emerging motor skill that allows infants to interact with the physical and social world. However, few studies have considered how reaching experiences shape infants’ own motor development and their perception of actions performed by others. In the current study, two groups of infants received daily parent guided play sessions over a 2-weeks training period. Using “Sticky Mittens”, one group was enabled to independently pick up objects whereas the other group only passively observed their parent’s actions on objects. Following training, infants’ manual and visual exploration of objects, agents, and actions in a live and a televised context were assessed. Our results showed that only infants who experienced independent object apprehension advanced in their reaching behavior, and showed changes in their visual exploration of agents and objects in a live setting. Passive observation was not sufficient to change infants’ behavior. To our surprise, the effects of the training did not seem to generalize to a televised observation context. Together, our results suggest that early motor training can jump-start infants’ transition into reaching and inform their perception of others’ actions.