Grasping of Real-World Objects Is Not Biased by Ensemble Perception

Abstract

The visual system is known to extract summary representations of visually similar objects which bias the perception of individual objects toward the ensemble average. Although vision plays a large role in guiding action, less is known about whether ensemble representation is informative for action. Motor behavior is tuned to the veridical dimensions of objects and generally considered resistant to perceptual biases. However, when the relevant grasp dimension is not available or is unconstrained, ensemble perception may be informative to behavior by providing gist information about surrounding objects. In the present study, we examined if summary representations of a surrounding ensemble display influenced grip aperture and orientation when participants reached-to-grasp a central circular target which had an explicit size but importantly no explicit orientation that the visuomotor system could selectively attend to. Maximum grip aperture and grip orientation were not biased by ensemble statistics during grasping, although participants were able to perceive and provide manual estimations of the average size and orientation of the ensemble display. Support vector machine classification of ensemble statistics achieved above-chance classification accuracy when trained on kinematic and electromyography data of the perceptual but not grasping conditions, supporting our univariate findings. These results suggest that even along unconstrained grasping dimensions, visually-guided behaviors toward real-world objects are not biased by ensemble processing.

Looking at the Ebbinghaus illusion: differences in neurocomputational requirements, not gaze-mediated attention, explain a classic perception-action dissociation

“…As a consequence of these more metric requirements, neural circuitry has evolved for the visual control of object-directed actions that is distinct from that mediating the visual perception of objects [ 4 , 42 ]. Recent work has shown, for example, that grasp aperture and grasp angle are refractory to the mean size and orientation of an ensemble of distractors around a target object [ 43 ], and that under conditions of attentional crowding, grasp aperture remains tuned to target size while manual estimates of target size do not [ 44 ].…”

The role of visual working memory in capacity-limited cross-modal ensemble coding

“…Translating this line of reasoning to the present study, the finding that ensemble perception of average taste is distinct from the operation of VWM does not suggest that these two cognitive systems do not interact whatsoever. Similarly, the finding that ensemble perception does not influence visuomotor behavior (i.e., reaching and grasping) does not imply that actions cannot be influenced by the perception of summary statistics (e.g., ensemble perception may contribute to memory-guided, as opposed to visually-guided, behavior; Fan et al, 2021). Future studies are needed to determine when and how different cognitive systems may interact during ensemble coding.…”

Visual Object Agnosia in Acute Ischemic Stroke: A First Neuroimaging Biomarker

“…Нарушение зрительного узнавания, согласно теории двух путей зрительной информации [4], патогенетически связано с поражением структур вентрального пути, следующего из затылочной коры в височную кору головного мозга [5]. Особую роль в идентификации объектов, сцен и лиц в системе этого пути играют так называемые объект-избирательные (objectselective), место-избирательные (place-selective) и лице-избирательные (face-selective) функциональные нейро нальные комплексы: их повреждение с высокой вероятностью приводит к развитию зрительной агнозии [6].…”