1 Department of Communication Sciences and Disorders, University of Haifa, Israel.
2 Baruch Ivcher School of Psychology, Interdisciplinary Center Herzliya, Israel.
Trends Hear. 2019 Jan-Dec;23:2331216519839624. doi: 10.1177/2331216519839624.
Individual differences in working memory capacity have been gaining recognition as playing an important role in speech comprehension, especially in noisy environments. Using the visual world eye-tracking paradigm, a recent study by Hadar and coworkers found that online spoken word recognition was slowed when listeners were required to retain in memory a list of four spoken digits (high load) compared with only one (low load). In the current study, we recognized that the influence of a digit preload might be greater for individuals who have a more limited memory span. We compared participants with higher and lower memory spans on the time course for spoken word recognition by testing eye-fixations on a named object, relative to fixations on an object whose name shared phonology with the named object. Results show that when a low load was imposed, differences in memory span had no effect on the time course of preferential fixations. However, with a high load, listeners with lower span were delayed by ∼550 ms in discriminating target from sound-sharing competitors, relative to higher span listeners. This follows an assumption that the interference effect of a memory preload is not a fixed value, but rather, its effect is greater for individuals with a smaller memory span. Interestingly, span differences affected the timeline for spoken word recognition in noise, but not offline accuracy. This highlights the significance of using eye-tracking as a measure for online speech processing. Results further emphasize the importance of considering differences in cognitive capacity, even when testing normal hearing young adults.
个体在工作记忆容量方面的差异已逐渐被认为在言语理解中起着重要作用，尤其是在嘈杂的环境中。最近，Hadar 及其同事使用视觉世界眼动追踪范式发现，当要求听众在记忆中保留四个数字（高负荷）而不是一个数字（低负荷）时，在线口语识别会变慢。在当前的研究中，我们认识到对于记忆跨度较小的个体，数字预加载的影响可能更大。我们比较了记忆跨度较高和较低的参与者在口语识别的时间进程上的眼动固定，通过测试命名对象的注视时间，相对于与命名对象具有相同发音的对象的注视时间。结果表明，当施加低负荷时，记忆跨度的差异对优先注视的时间进程没有影响。然而，在高负荷下，与记忆跨度较高的听众相比，记忆跨度较低的听众在区分目标和声音共享竞争者时会延迟约 550ms。这是基于这样的假设，即记忆预加载的干扰效应不是一个固定的值，而是对于记忆跨度较小的个体，其效应更大。有趣的是，跨度差异会影响噪声中的口语识别时间线，但不会影响离线准确性。这凸显了使用眼动追踪作为在线言语处理测量手段的重要性。研究结果进一步强调了考虑认知能力差异的重要性，即使在测试正常听力的年轻成年人时也是如此。
