Supplementary data for the paper 'A role of peripheral vision in chess? Evidence from a gaze-contingent method'

Chunking theory and previous eye-tracking studies suggest that expert chess players use peripheral vision to judge chess positions and determine the best moves to play. However, the role of peripheral vision in chess has largely been inferred rather than tested through controlled experimentation. In this study, we used a gaze-contingent paradigm in a reconstruction task, similar to the one initially used by De Groot (1946). It was hypothesized that the smaller the gaze-contingent window while memorizing a chess position, the smaller the differences in reconstruction accuracy between novice and expert players. Participants viewed 30 chess positions for 20 seconds, after which they reconstructed this position. This was done for four different window sizes as well as for full visibility of the board. The results, as measured by Cohen’s <em>d</em> effect sizes between experts and novices of the proportion of correctly placed pieces, supported the above hypothesis, with experts performing much better but losing much of their performance advantage for the smallest window size. A complementary find-the-best-move task and additional eye-movement analyses showed that experts had a longer median fixation duration and more spatially concentrated scan patterns than novice players. These findings suggest a key contribution of peripheral vision and are consistent with the prevailing chunking theory.

组块理论（chunking theory）与既往眼动研究均表明，国际象棋专家棋手会借助外周视觉（peripheral vision）判断棋局态势，并敲定最优走法。然而，国际象棋领域中，外周视觉的作用大多仅为推论所得，尚未通过控制性实验得到验证。本研究采用了与德格鲁特（De Groot, 1946）最初使用的范式相似的注视依赖范式（gaze-contingent paradigm），开展棋局重构任务。本研究提出如下假设：棋手在记忆棋局时，其注视依赖窗口越小，新手与专家棋手之间的重构准确性差异就越小。实验中，参与者需观察30个棋局共20秒，随后完成该棋局的重构任务。该流程分别在四种不同尺寸的注视窗口以及棋盘全可见的条件下开展。以专家与新手间棋子摆放正确率的科恩d效应量（Cohen’s <em>d</em> effect size）作为衡量指标，实验结果验证了前述假设：专家棋手的表现显著优于新手，但在最小窗口条件下，二者的表现优势差距大幅缩小。补充开展的最优走法搜寻任务与额外眼动分析结果显示，相较于新手棋手，专家棋手的中位数注视时长更长，且扫视模式的空间集中度更高。上述研究结果证实了外周视觉在棋局处理中的关键作用，同时也与主流的组块理论相符。