Morales Jorge, Solovey Guillermo, Maniscalco Brian, Rahnev Dobromir, de Lange Floris P, Lau Hakwan
Department of Philosophy, Columbia University, 708 Philosophy Hall, 1150 Amsterdam Avenue, Mail Code: 4971, New York, NY, 10027, USA,
Atten Percept Psychophys. 2015 Aug;77(6):2021-36. doi: 10.3758/s13414-015-0897-2.
When visual attention is directed away from a stimulus, neural processing is weak and strength and precision of sensory data decreases. From a computational perspective, in such situations observers should give more weight to prior expectations in order to behave optimally during a discrimination task. Here we test a signal detection theoretic model that counter-intuitively predicts subjects will do just the opposite in a discrimination task with two stimuli, one attended and one unattended: when subjects are probed to discriminate the unattended stimulus, they rely less on prior information about the probed stimulus' identity. The model is in part inspired by recent findings that attention reduces trial-by-trial variability of the neuronal population response and that they use a common criterion for attended and unattended trials. In five different visual discrimination experiments, when attention was directed away from the target stimulus, subjects did not adjust their response bias in reaction to a change in stimulus presentation frequency despite being fully informed and despite the presence of performance feedback and monetary and social incentives. This indicates that subjects did not rely more on the priors under conditions of inattention as would be predicted by a Bayes-optimal observer model. These results inform and constrain future models of Bayesian inference in the human brain.
当视觉注意力从一个刺激上转移时，神经处理就会变弱，感觉数据的强度和精度也会降低。从计算的角度来看，在这种情况下，观察者应该更重视先验期望，以便在辨别任务中表现得最优。在此，我们测试了一个信号检测理论模型，该模型做出了与直觉相反的预测：在有两个刺激（一个被关注，一个未被关注）的辨别任务中，受试者的行为会相反；当受试者被要求辨别未被关注的刺激时，他们较少依赖关于被探测刺激身份的先验信息。该模型部分受到最近研究结果的启发，即注意力会降低神经元群体反应的逐次试验变异性，并且他们对被关注和未被关注的试验使用共同的标准。在五个不同的视觉辨别实验中，当注意力从目标刺激上转移时，尽管受试者已得到充分告知，且存在绩效反馈以及金钱和社会激励，但他们并未根据刺激呈现频率的变化来调整反应偏差。这表明，在注意力不集中的情况下，受试者并未如贝叶斯最优观察者模型所预测的那样更多地依赖先验信息。这些结果为人类大脑中贝叶斯推理的未来模型提供了信息并对其进行了限制。
