The John B. Pierce Laboratory, New Haven, CT 06519, USA.
Chem Senses. 2012 Mar;37(3):263-77. doi: 10.1093/chemse/bjr103. Epub 2011 Nov 10.
Odorants and flavorants typically contain many components. It is generally easier to detect multicomponent stimuli than to detect a single component, through either neural integration or probability summation (PS) (or both). PS assumes that the sensory effects of 2 (or more) stimulus components (e.g., gustatory and olfactory components of a flavorant) are detected in statistically independent channels, that each channel makes a separate decision whether a component is detected, and that the behavioral response depends solely on the separate decisions. Models of PS traditionally assume high thresholds for detecting each component, noise being irrelevant. The core assumptions may be adapted, however, to signal-detection theory, where noise limits detection. The present article derives predictions of high-threshold and signal-detection models of independent-decision PS in detecting gustatory-olfactory flavorants, comparing predictions in yes/no and 2-alternative forced-choice tasks using blocked and intermixed stimulus designs. The models also extend to measures of response times to suprathreshold flavorants. Predictions derived from high-threshold and signal-detection models differ markedly. Available empirical evidence on gustatory-olfactory flavor detection suggests that neither the high-threshold nor the signal-detection versions of PS can readily account for the results, which likely reflect neural integration in the flavor system.
气味剂和调味剂通常含有多种成分。通过神经整合或概率总和（PS）（或两者兼而有之），通常更容易检测到多成分刺激，而不是检测单个成分。PS 假设两种（或更多）刺激成分（例如，调味剂的味觉和嗅觉成分）的感觉效应在统计上独立的通道中被检测到，每个通道单独决定是否检测到一个成分，并且行为反应仅取决于单独的决定。PS 的传统模型假设每个成分的检测阈值较高，噪声无关紧要。然而，可以对核心假设进行调整，以适应信号检测理论，其中噪声限制了检测。本文推导了用于检测味觉-嗅觉调味剂的独立决策 PS 的高阈值和信号检测模型的预测，使用阻塞和混合刺激设计比较了在是/否和 2 种替代强制选择任务中的预测。该模型还扩展到了超阈值调味剂的反应时间测量。高阈值和信号检测模型得出的预测差异很大。关于味觉-嗅觉调味剂检测的现有经验证据表明，PS 的高阈值和信号检测版本都不容易解释这些结果，这可能反映了调味系统中的神经整合。
