Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA.
Brain Behav. 2023 Dec;13(12):e3312. doi: 10.1002/brb3.3312. Epub 2023 Nov 15.
Many theories contend that evidence accumulation is a critical component of decision-making. Cognitive accumulation models typically interpret two main parameters: a drift rate and decision threshold. The former is the rate of accumulation, based on the quality of evidence, and the latter is the amount of evidence required for a decision. Some studies have found neural signals that mimic evidence accumulators and can be described by the two parameters. However, few studies have related these neural parameters to experimental manipulations of sensory data or memory representations. Here, we investigated the influence of affective salience on neural accumulation parameters. High affective salience has been repeatedly shown to influence decision-making, yet its effect on neural evidence accumulation has been unexamined.
The current study used a two-choice object categorization task of body images (feet or hands). Half the images in each category were high in affective salience because they contained highly aversive features (gore and mutilation). To study such quick categorization decisions with a relatively slow technique like functional magnetic resonance imaging, we used a gradual reveal paradigm to lengthen cognitive processing time through the gradual "unmasking" of stimuli.
Because the aversive features were task-irrelevant, high affective salience produced a distractor effect, slowing decision time. In visual accumulation regions of interest, high affective salience produced a longer time to peak activation. Unexpectedly, the later peak appeared to be the product of changes to both drift rate and decision threshold. The drift rate for high affective salience was shallower, and the decision threshold was greater. To our knowledge, this is the first demonstration of an experimental manipulation of sensory data or memory representations that changed the neural decision threshold.
These findings advance our knowledge of the neural mechanisms underlying affective responses in general and the influence of high affective salience on object representations and categorization decisions.
许多理论认为，证据积累是决策的一个关键组成部分。认知积累模型通常解释两个主要参数：漂移率和决策阈值。前者是基于证据质量的积累率，后者是做出决策所需的证据量。一些研究发现了模拟证据积累器的神经信号，并可以用这两个参数来描述。然而，很少有研究将这些神经参数与对感觉数据或记忆表示的实验操作联系起来。在这里，我们研究了情感显著性对神经积累参数的影响。高情感显著性已被反复证明会影响决策，但它对神经证据积累的影响尚未得到检验。
本研究使用了一个关于身体图像（脚或手）的二选一物体分类任务。每个类别中的一半图像具有较高的情感显著性，因为它们包含高度厌恶的特征（血腥和残缺）。为了使用功能磁共振成像等相对较慢的技术研究这种快速的分类决策，我们使用了逐渐揭示范式，通过逐渐“揭示”刺激来延长认知处理时间。
由于厌恶特征与任务无关，高情感显著性产生了分心效应，从而延长了决策时间。在视觉积累的感兴趣区域，高情感显著性导致激活的峰值出现时间更长。出乎意料的是，后来的峰值似乎是漂移率和决策阈值变化的结果。高情感显著性的漂移率较浅，决策阈值较大。据我们所知，这是首次证明实验操纵感觉数据或记忆表示会改变神经决策阈值。
这些发现增进了我们对情感反应的神经机制的认识，特别是对高情感显著性对物体表示和分类决策的影响的认识。
