RESUMEN
Representing objects as continuous across time requires the establishment of correspondence, whereby current stimuli are represented as deriving from the same object as earlier stimuli. Spatiotemporal continuity and surface-feature similarity play important roles in these correspondence processes. Because objects are often represented across extended periods of time, visual working memory (VWM) content should also play a role in object correspondence. We tested this prediction using Ternus motion. Displays consisted of three-disk arrays that shifted horizontally by one position between frames. Depending on how correspondence is resolved, Ternus displays are perceived as group motion, where all three disks appear to move together, or element motion, where one disk appears to jump across the others. Reports of which motion is perceived provide an index of how correspondence was resolved. Ternus displays were adapted such that the color of some disks biased element motion while the color of others biased group motion. Maintaining one or the other of the colors in VWM for later report systematically biased which type of motion was perceived (Experiments 1 and 2). When color was incidental to the VWM task, however, it did not (Experiment 3). These results confirm that VWM content contributes to object correspondence. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
Asunto(s)
Memoria a Corto Plazo , Percepción de Movimiento , Humanos , Movimiento (Física)RESUMEN
The visual system constructs perceptions based on ambiguous information. For motion perception, the correspondence problem arises, i.e., the question of which object went where. We asked at which level of processing correspondence is solved - lower levels based on information that is directly available in the retinal input or higher levels based on information that has been abstracted beyond the input directly available at the retina? We used a Ponzo-like illusion to manipulate the perceived size and separations of elements in an ambiguous apparent motion display. Specifically, we presented Ternus displays - for which the type of motion that is perceived depends on how correspondence is resolved - at apparently different distances from the viewer using pictorial depth cues. We found that the perception of motion depended on the apparent depth of the displays, indicating that correspondence processes utilize information that is produced at higher-level processes.
Asunto(s)
Percepción de Profundidad/fisiología , Ilusiones/fisiología , Percepción de Movimiento/fisiología , Adulto , HumanosRESUMEN
Temporal attention, that is, the process of anticipating the occurrence of a stimulus at a given time point, has been shown to improve perceptual processing of visual stimuli. In the present study, we investigated whether and how temporal attention interacts with spatial attention and feature-based attention in visual selection. To monitor the influence of the three different attention dimensions on perceptual processing, we measured event-related potentials (ERPs). Our participants performed a visual search task, in which a colored singleton was presented amongst homogenous distractors. We manipulated spatial and feature-based attention by requiring participants to respond only to target singletons in a particular color and at a to-be-attended spatial location. We manipulated temporal attention by means of an explicit temporal cue that announced either validly or invalidly the occurrence of the search display. We obtained early ERP effects of spatial attention and feature-based attention at the validly cued but not at the invalidly cued time point. Taken together, our results suggest that temporal attention boosts early effects of spatial and feature-based attention.
Asunto(s)
Atención , Señales (Psicología) , Humanos , Estimulación Luminosa , Tiempo de Reacción , Percepción VisualRESUMEN
Our visual system is able to establish associations between corresponding images across space and time and to maintain the identity of objects, even though the information our retina receives is ambiguous. It has been shown that lower level factors-as, for example, spatiotemporal proximity-can affect this correspondence problem. In addition, higher level factors-as, for example, semantic knowledge-can influence correspondence, suggesting that correspondence might also be solved at a higher object-based level of processing, which could be mediated by attention. To test this hypothesis, we instructed participants to voluntarily direct their attention to individual elements in the Ternus display. In this ambiguous apparent motion display, three elements are aligned next to each other and shifted by one position from one frame to the next. This shift can be either perceived as all elements moving together (group motion) or as one element jumping across the others (element motion). We created a competitive Ternus display, in which the color of the elements was manipulated in such a way that the percept was biased toward element motion for one color and toward group motion for another color. If correspondence can be established at an object-based level, attending toward one of the biased elements should increase the likelihood that this element determines the correspondence solution and thereby that the biased motion is perceived. Our results were in line with this hypothesis providing support for an object-based correspondence process that is based on a one-to-one mapping of the most similar elements mediated via attention.
Asunto(s)
Atención , Sesgo , Humanos , Movimiento (Física) , Percepción de Movimiento , Estimulación Luminosa , RetinaRESUMEN
Our visual system establishes correspondence between objects and thus enables us to perceive an object, like a car on the road, as moving continuously. A central question regarding correspondence is whether our visual system uses relatively unprocessed image-based information or further processed object-based information to establish correspondence. While it has been shown that some object-based attributes, such as perceived lightness, can influence correspondence, manipulating object-based information typically involves at least minimal changes of image-based information as well, making it difficult to clearly distinguish between the two levels. To avoid this confound, we manipulated object-based information prior to the task in which we measured correspondence. We used 3-element Ternus displays to assess correspondence. These are ambiguous apparent-motion displays that, depending on how correspondence is solved, are perceived as either one element jumping across the others or as all three elements moving together as a group. We manipulated object-based information by presenting one of two object histories prior to the Ternus display. In one, they moved or changed luminance independently, and thus appeared independent from each other. In the other, the elements moved or changed their luminance all together and thus appeared grouped with each other. We found that the object history did influence how the Ternus displays were perceived, thereby confirming that object-based information alone can be used as a basis for establishing correspondence in line with object-based theories of correspondence.
Asunto(s)
Percepción de Movimiento , Rol , Humanos , Movimiento (Física) , Visión OcularRESUMEN
It is well-known that our eyes typically fixate those objects in a scene, with which interactions are about to unfold. During manual interactions, our eyes usually anticipate the next subgoal and thus serve top-down, goal-driven information extraction requirements, probably driven by a schema-based task representation. On the other hand, motor control research concerning object manipulations has extensively demonstrated how grasping choices are often influenced by deeper considerations about the final goal of manual interactions. Here we show that also these deeper considerations are reflected in early eye fixation behavior, significantly before the hand makes contact with the object. In this study, subjects were asked to either pretend to drink out of the presented object or to hand it over to the experimenter. The objects were presented upright or upside down, thus affording a thumb-up (prone) or a thumb-down (supine) grasp. Eye fixation data show a clear anticipatory preference for the region where the index finger is going to be placed. Indeed, fixations highly correlate with the final index finger position, thus subserving the planning of the actual manual action. Moreover, eye fixations reveal several orders of manual planning: Fixation distributions do not only depend on the object orientation but also on the interaction task. These results suggest a fully embodied, bidirectional sensorimotor coupling of eye-hand coordination: The eyes help in planning and determining the actual manual object interaction, considering where to grasp the presented object in the light of the orientation and type of the presented object and the actual manual task to be accomplished with the object.