Universal Coding for Uncertainty?

To make decisions in a fluctuating environment, it can be helpful to anticipate upcoming events by estimating their likelihood. For highly probable or improbable events, we can be fairly certain about our estimates. However, events are often more stochastic, and hence our likelihood estimations become uncertain. Encoding of such uncertainty is particularly motivationally relevant when the events are related to desirable or detrimental outcomes (e.g., “is this road the fastest route to my destination right now?”). In contrast, the encoding of uncertainty of neutral events is less motivationally relevant; but it can still be useful if it provides general knowledge about the environment (e.g., “is the road generally busy?”). These two forms of uncertainty are called valenced uncertainty and generic uncertainty. Despite their qualitative difference, both forms of uncertainty provide adaptive value for reacting to the environment. A fundamental question is whether a universal coding mechanism is used to represent all forms of uncertainty or if instead uncertainty is represented differently depending on the motivational value. The human brain has widely been reported to use a universal coding mechanism in valuation systems. The neural common currency hypothesis suggests that for choices of all kinds, even qualitatively different (e.g., money, food, goods), goodness or utility is encoded in the same ventromedial prefrontal cortex (vmPFC) region; this hypothesis has received support from multiple lines of research (Levy and Glimcher, 2012). Since value representations are closely tied to uncertainty in decision-making, it is possible that a universal coding mechanism also applies to the encoding of different forms of uncertainty. On the other hand, other studies have revealed that valenced words are better memorized and recalled than neutral words (Megalakaki et al., 2019). This suggests that valenced and neutral information are processed differently. Moreover, a Darwinian … Correspondence should be addressed to Chun-Kit Law at kelvinck.law{at}gmail.com.