Temporal aspects of auditory intensity processing

第一个项目阶段的实验证实了一个假设，即对目标音调的选择性注意的失败是一个有用的框架，用于理解非同时掩蔽对强度分辨率的有时显着影响。在我们的实验中，我们观察到在时间掩蔽下，强度差异阈值的个体间差异惊人（高达20 dB）。考虑到我们测试的是听力正常、认知能力高的年轻听众（大学生），这些结果更令人惊讶。在非同时掩蔽下的强度辨别研究和信息掩蔽实验中也报道了类似的结果，其中选择注意也被认为起重要作用。本提案中提出的实验的第一个目的是测试控制选择性注意的一般能力是非同时掩蔽下强度分辨率的决定因素的假设。为此，我们将从认知心理学的两个经典任务中测量选择性注意的空间和时间控制。此外，我们将测量工作记忆广度和几种基本听觉能力（如听觉时间精细结构的敏感性，间隙检测）。我们预计前向掩蔽下的强度分辨率与评估选择性注意控制任务的表现相关，但与基本听觉加工的相关性较弱。提出的项目的第二个目的是测试假设，即非同时掩蔽下的强度分辨率是复杂通信环境中语音识别的预测因子。最近的研究表明，当目标演讲者与竞争演讲者一起出现（“鸡尾酒会情况”）时，正常听力的听众的个体间差异很大。我们推测，在这种情况下，像控制选择性注意这样的中心机制再次发挥了重要作用。使用相关分析，我们将确定那些性能指标（时间掩蔽下的强度分辨率，基本听觉处理，选择性注意控制，工作记忆广度），最好地预测在鸡尾酒会设置语音识别。我们将模拟几个鸡尾酒会环境，这些环境在能量和信息掩蔽的存在、时间精细结构的重要性以及竞争演讲者的数量方面有所不同。

The experiments of the first project phase confirmed the hypothesis that the failure of selective attention to the target tones is a useful framework for understanding the sometimes dramatic effects of non-simultaneous masking on intensity resolution. In our experiments, we observed astonishingly large inter-individual differences (up to 20 dB) in the intensity difference limens under temporal masking. Considering that we tested normally hearing young listeners with high cognitive abilities (university students) these results are even more surprising. Similar results were reported in previous studies on intensity discrimination under non-simultaneous masking, and in experiments on informational masking, where selective attention is also assumed to play an important role. The first aim of the experiments put forth in this proposal is to test the hypothesis that a general capability of controlling selective attention is a determinant of intensity resolution under non-simultaneous masking. To this end, we will measure the spatial and temporal control of selective attention in two classical tasks from cognitive psychology. In addition, we will measure the working memory span and several basic auditory abilities (e.g., sensitivity for the auditory temporal fine structure, gap detection). We expect the intensity resolution under forward masking to be correlated with performance in the tasks assessing the control of selective attention, but only weak correlations with basic auditory processing. The second aim of the proposed project is to test the hypothesis that intensity resolution under non-simultaneous masking is a predictor for speech recognition in complex communication settings. Recent studies reported large inter-individual differences in normally hearing listeners when a target speaker was presented together with competing speakers ("cocktail party situation"). We conjecture that in this situation central mechanisms like the control of selective attention again play an important role. Using correlation analyses, we will identify those performance measures (intensity resolution under temporal masking, basic auditory processing, control of selective attention, working memory span) that best predict speech recognition in a cocktail party setting. We will simulate several cocktail party environments that differ with respect to the presence of energetic and informational masking, the importance of the temporal fine structure, and the number of competing speakers.