Chastain G
J Exp Psychol Hum Percept Perform. 1985 Dec;11(6):752-64. doi: 10.1037//0096-1523.11.6.752.
A parafoveally presented letter is more accurately identified when flanked by a letter to its foveal side than when flanked by one to its peripheral side, but only if the two letters are nonconfusable. With confusable letters there is no such relative position effect. Four experiments indicated that the basis for this confusability-asymmetry interaction is not criterion or response bias, but rather that it occurs earlier in visual processing. In Experiment 1 the interaction was found when only one pair member was reported, thus eliminating response bias requiring the report of both letters as the source of the effect. In Experiment 2 the data were subjected to signal detection analysis, and the interaction persisted. In Experiment 3 pair members were presented simultaneously or in rapid sequence, and the interaction was found only with simultaneous presentations. In Experiment 4 letters were used with upper- and lowercase counterparts that were quite different in shape. Uppercase letters that were most and least confusable for each subject were paired for presentation in their upper case form or in mixed-case form. The interaction occurred only with upper-case pairs.
当中央凹旁呈现的字母其凹侧被另一个字母包围时，比其外周侧被字母包围时能更准确地识别，但前提是这两个字母不会混淆。对于易混淆的字母，不存在这种相对位置效应。四项实验表明，这种混淆性与不对称性相互作用的基础不是标准或反应偏差，而是它发生在视觉处理的更早阶段。在实验1中，当只报告一对字母中的一个时发现了这种相互作用，从而消除了需要报告两个字母才产生效应的反应偏差。在实验2中，对数据进行了信号检测分析，这种相互作用依然存在。在实验3中，成对字母同时呈现或快速相继呈现，结果发现只有同时呈现时才会出现这种相互作用。在实验4中，使用了形状差异很大的大写和小写字母。为每个受试者将最易混淆和最不易混淆的大写字母配对，以大写形式或大小写混合形式呈现。这种相互作用只出现在大写字母对中。
