ABSTRACT

Background: Previous studies on perceptual letter-matching have found that younger and older adults showed “fast-same” effects for response time and “false-different” effects for errors but the effects were more pronounced for older adults. According to the Noisy Operator Theory, internal noise in visual processing distorts “same” trials into appearing different whereas distortion for “different” trials does not affect performance. Older adults have a “noisier” representation of items within perceptual processing which can impact perceptual matching. However, EEG measures may provide a more direct measure of letter-matching decisions.

Methods: We measured the P300 event-related potential (ERP) amplitude, an index of familiarity in stimulus categorization, and behavioral measures (response time and accuracy) to assess letter-matching performance.

Results: Individuals responded faster to “same” trials than to “different” trials but were less accurate. Older adults showed similar P300 amplitudes across trial type whereas younger adults produced a larger amplitude for “same” than “different” trials, suggesting that older adults showed less familiarity for “same” trials than did younger adults – a prediction of the Noisy Operator Theory.

Conclusions: These ERP results are consistent with the Noisy Operator Theory – suggesting that an age-related increase in internal noise affected letter-matching performance.

摘要

背景：先前有关知觉字母匹配的研究发现，年轻人和老年人对响应时间表现出“快速相同”的影响，而对于错误表现出“假不同”的影响，但这种影响在老年人中更为明显。根据嘈杂算子理论，视觉处理中的内部噪声会使“相同”的试验失真，使它们看起来不同，而“不同”的试验的失真不会影响性能。老年人在感知过程中对项目的“嘈杂”表示会影响感知匹配。但是，EEG度量可能会提供更直接的字母匹配决策度量。

方法：我们测量了P300事件相关电位（ERP）幅度，对刺激分类的熟悉程度以及行为量度（响应时间和准确性）以评估字母匹配性能。

结果：个人对“相同”试验的反应比对“不同”试验的反应更快，但准确性较差。老年人在不同的试验类型中显示出相似的P300振幅，而年轻人对“相同”试验产生的振幅大于“不同”试验，这表明，老年人对“相同”试验的熟悉度小于​​年轻人，这是对噪声操作者理论的预测。

结论：这些ERP结果与“嘈杂算子理论”一致-暗示与年龄相关的内部噪声增加会影响字母匹配性能。