Supplementary data for the paper 'A role of peripheral vision in chess? Evidence from a gazecontingent 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，资深国际象棋棋手会借助周边视觉（Peripheral Vision）评判棋局态势并选定最优走法。然而，学界此前大多仅通过推论而非对照实验来验证周边视觉在国际象棋对弈中的作用。本研究在重构任务中采用了注视依存范式（Gaze-Contingent Paradigm），该范式与De Groot（1946）最初使用的范式相似。本研究提出如下假设：在记忆棋局时，注视依存窗口越小，新手与资深棋手之间的重构准确率差异就越小。受试者需观察30个棋局共20秒，随后完成该棋局的重构任务。实验共设置四种不同尺寸的注视依存窗口，并增设了棋盘全可见的对照组。以专家与新手间正确摆放棋子比例的科恩d值（Cohen's d）效应量作为衡量指标的实验结果，验证了上述假设：资深棋手的整体重构表现显著优于新手，但在最小尺寸的注视依存窗口条件下，其表现优势大幅缩减。一项补充的"寻找最优走法"任务与额外的眼动分析结果显示，相较于新手，资深棋手的中位注视时长更长，且扫描模式在空间上更为集中。上述实验结果表明周边视觉在棋局处理中起到关键作用，且与主流的组块理论相符。