Can the macro beat the micro? Integrated information across spatiotemporal scales
Can the macro beat the micro? Integrated information across spatiotemporal scales
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DOI：
10.1093/nc/niw012
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发表时间：
2016-01-01
影响因子：
4.1
通讯作者：
Tononi, Giulio
中科院分区：
文献类型：
--
作者：
Hoel, Erik P.;Albantakis, Larissa;Tononi, Giulio
复杂系统（如大脑）中的因果相互作用可以在多个时空层次上进行分析。人们普遍认为微观层面的因果关系是完整的，因此排除了宏观层面的因果关系。然而，通过测量有效信息一个系统的机制在多大程度上限制了它的过去和未来的状态我们最近表明，因果力量在宏观层面上比微观层面上更强。在这项工作中，我们超越了有效的信息，并考虑从系统的内在视角适当衡量因果力的额外要求：组成（部分的因果力），状态依赖（系统在特定状态下的因果力）;整合（整体对其部分的因果不可约化）和排除（系统的因果边界）。满足这些要求的措施，称为U最大，开发的背景下，综合信息理论。在这里，我们使用简化的类神经元系统在空间和时间的微观和宏观层面上系统地评估U Max。我们表明，系统的特点是不确定性和/或退化，U确实可以在宏观层面上达到峰值。如果粗粒化的微观元素产生具有高度不可约因果选择性的宏观机制，就会发生这种情况。这些结果与意识的理论解释有关，因为对于整合信息理论，整合信息的时空最大值确定了意识的时空尺度。更一般地说，这些结果表明，宏观因果出现和微观因果排除的概念举行时，因果关系的力量进行全面评估，并从系统的内在角度。
Causal interactions within complex systems such as the brain can be analyzed at multiple spatiotemporal levels. It is widely assumed that the micro level is causally complete, thus excluding causation at the macro level. However, by measuring effective information-how much a system's mechanisms constrain its past and future states-we recently showed that causal power can be stronger at macro rather than micro levels. In this work, we go beyond effective information and consider additional requirements of a proper measure of causal power from the intrinsic perspective of a system: composition (the cause-effect power of the parts), state-dependency (the cause-effect power of the system in a specific state); integration (the causal irreducibility of the whole to its parts), and exclusion (the causal borders of the system). A measure satisfying these requirements, called U Max, was developed in the context of integrated information theory. Here, we evaluate U Max systematically at micro and macro levels in space and time using simplified neuronal-like systems. We show that for systems characterized by indeterminism and/or degeneracy, U can indeed peak at a macro level. This happens if coarse-graining micro elements produces macro mechanisms with high irreducible causal selectivity. These results are relevant to a theoretical account of consciousness, because for integrated information theory the spatiotemporal maximum of integrated information fixes the spatiotemporal scale of consciousness. More generally, these results show that the notions of macro causal emergence and micro causal exclusion hold when causal power is assessed in full and from the intrinsic perspective of a system.