Drawing from Memory: Hand-Eye Coordination at Multiple Scales

Eyes move to gather visual information for the purpose of guiding behavior. This guidance takes the form of perceptual-motor interactions on short timescales for behaviors like locomotion and hand-eye coordination. More complex behaviors require perceptual-motor interactions on longer timescales mediated by memory, such as navigation, or designing and building artifacts. In the present study, the task of sketching images of natural scenes from memory was used to examine and compare perceptual-motor interactions on shorter and longer timescales. Eye and pen trajectories were found to be coordinated in time on shorter timescales during drawing, and also on longer timescales spanning study and drawing periods. The latter type of coordination was found by developing a purely spatial analysis that yielded measures of similarity between images, eye trajectories, and pen trajectories. These results challenge the notion that coordination only unfolds on short timescales. Rather, the task of drawing from memory evokes perceptual-motor encodings of visual images that preserve coarse-grained spatial information over relatively long timescales as well.

眼球运动的核心功能为采集视觉信息，以指导行为活动。这类指导以感知运动交互（perceptual-motor interaction）的形式，在短时间尺度上支撑行进、手眼协调等基础行为。更为复杂的行为则需要依托记忆介导的长时尺度感知运动交互，例如导航、设计与建造人工制品。本研究采用从记忆中绘制自然场景图像的任务，旨在考察并对比短、长时尺度下的感知运动交互。研究结果显示，在绘画过程的短时尺度内，眼球与笔的运动轨迹存在时间维度的协同；而在涵盖图像学习与绘画阶段的长时尺度中，二者同样存在协同效应。后一类协同效应通过构建纯空间分析方法得以识别，该方法可计算图像、眼球运动轨迹与笔运动轨迹三者间的相似性量化指标。上述结果挑战了"协同仅发生于短时尺度"的既有认知。进一步而言，从记忆中绘画的任务会唤起视觉图像的感知运动编码，这类编码同样能够在相对较长的时间尺度上保留粗粒度空间信息。