Shan Jiangang, Hajonides Jasper E, Myers Nicholas E
Department of Psychology, University of Wisconsin-Madison, USA.
Oxford Centre for Human Brain Activity & Department of Experimental Psychology, Wellcome Centre for Integrative Neuroimaging, University of Oxford, UK.
bioRxiv. 2024 Nov 18:2024.11.18.624176. doi: 10.1101/2024.11.18.624176.
Recall of stimuli is biased by stimulus history, variously manifested as an attractive bias toward or repulsive bias from previous stimuli (i.e., serial dependence). It is unclear when attractive vs repulsive biases arise and if they share neural mechanisms. A recent model of attractive serial dependence proposes a two-stage process in which adaptation causes a repulsive bias during encoding that is later counteracted by an attractive bias at the decision-making stage in a Bayesian-inference-like manner. Neural evidence exists for a repulsive bias at encoding, but evidence for the attractive bias during the response period has been more elusive. We recently [1] showed that while different stimuli in trial history exerted different (attractive or repulsive) serial biases on behavioral reports, during encoding the neural representation of the current item was always repulsively biased. Here we assessed whether this discrepancy between neural and behavioral effects is resolved during subsequent decision-making. Multivariate decoding of magnetoencephalography data during working memory recall showed a neural distinction between attractive and repulsive biases: an attractive neural bias emerged only late in recall. But stimuli that created a repulsive bias on behavior led to a repulsive neural bias early in the recall phase, suggesting that it had already been incorporated earlier. Our results suggest that attractive (but not repulsive) serial dependence arises during decision-making, and that priors that influence post-perceptual decision-making are updated by the previous trial's target, but not by other stimuli.
对刺激的回忆会受到刺激历史的影响，表现为对先前刺激的吸引偏向或排斥偏向（即序列依赖性）。目前尚不清楚吸引偏向与排斥偏向何时出现，以及它们是否共享神经机制。最近一个关于吸引性序列依赖性的模型提出了一个两阶段过程，在这个过程中，适应在编码过程中产生排斥偏向，随后在决策阶段以类似贝叶斯推理的方式被吸引偏向抵消。有神经证据表明在编码时有排斥偏向，但在反应期存在吸引偏向的证据却更难捉摸。我们最近[1]表明，虽然试验历史中的不同刺激对行为报告产生了不同（吸引或排斥）的序列偏向，但在编码过程中，当前项目的神经表征总是存在排斥偏向。在这里，我们评估了神经效应和行为效应之间的这种差异在后续决策过程中是否得到解决。在工作记忆回忆期间对脑磁图数据进行多变量解码，结果显示吸引偏向和排斥偏向在神经层面上存在区别：吸引性神经偏向仅在回忆后期出现。但那些对行为产生排斥偏向的刺激在回忆阶段早期就导致了排斥性神经偏向，这表明它在更早的时候就已经被纳入了。我们的结果表明，吸引性（而非排斥性）序列依赖性在决策过程中出现，并且影响感知后决策的先验信息是由前一次试验的目标更新的，而不是由其他刺激更新的。
