Data for "Piercing of consciousness as a threshold crossing operation"

Many decisions arise through an accumulation of evidence to a terminating threshold. The process, termed bounded evidence accumulation (or drift-diffusion), provides a unified account of decision speed and accuracy, and it is supported by neurophysiology in human and animal models. In many situations, a decision maker may not communicate a decision immediately and yet feel that at some point she had made up her mind. We hypothesized that this occurs when an accumulation of evidence reaches a termination threshold, registered, subjectively, as an “aha” moment. We asked human participants to make perceptual decisions about the net direction of dynamic random dot motion. The difficulty and viewing duration were controlled by the experimenter. After indicating their choice, participants adjusted the setting of a clock to the moment they felt they had reached a decision. The subjective decision times (tSD) were faster on trials with stronger (easier) motion, and they were well fit by a bounded drift-diffusion model. The fits to the tSD alone furnished parameters that fully predicted the choices (accuracy) of four of the five participants. The quality of the prediction provides compelling evidence that these subjective reports correspond to the terminating process of a decision, rather than a post hoc inference or arbitrary report. Thus, conscious awareness of having reached a decision appears to arise when the brain’s representation of accumulated evidence reaches a threshold or bound. We propose that such a mechanism might play a more widespread role in the “piercing of consciousness" by non-conscious thought processes.

许多决策源于证据积累至某个终止阈值的过程。这一过程被称为有限证据积累（bounded evidence accumulation，或漂移扩散模型 drift-diffusion），它为决策速度与准确性提供了统一解释框架，并得到人类及动物模型神经生理学研究的支持。

在诸多情境中，决策者可能不会立即表达其决策，但会在某个时刻感觉到自己已下定决心。我们假设，这种情况发生于证据积累达到终止阈值时——此时主观上会产生“顿悟”（"aha" moment）的体验。

我们要求人类被试对动态随机点运动的净方向做出知觉决策。实验者控制了任务难度与观察时长。在表明选择后，参与者需调整时钟设置，标记出他们感觉自己已做出决策的时刻。

在运动信号更强（更易）的试次中，主观决策时间（tSD）更短，且这些数据能被有限漂移扩散模型很好地拟合。仅基于主观决策时间的拟合结果所提供的参数，即可完全预测五位参与者中四位的选择（准确性）。

预测结果的质量提供了强有力的证据，表明这些主观报告对应决策的终止过程，而非事后推断或随意报告。因此，当大脑中积累证据的表征达到某个阈值时，便会产生已做出决策的意识觉知。我们提出，这种机制或许在无意识思维过程“穿透意识”的现象中扮演更广泛的角色。