Common computations for metacognition and meta-metacognition

Cognition and metacognition are often conceptualized as two separate systems. These systems are typically assumed to depend on different neural substrates and to have access to different information. Despite its dominance, this conceptualization remains controversial. Here we sought to examine a related distinction that carries less historical baggage: the distinction between metacognition and meta-metacognition. Participants (N = 40) performed a perceptual decision-making task and provided (1) an object-level, Type-1 response about the identity of the stimulus, (2) a metacognitive, Type-2 response (low/high) regarding their confidence in their Type-1 decision, and (3) a meta-metacognitive, Type-3 response (low/high) regarding the quality of their Type-2 rating. We found strong evidence for the existence of Type-3, meta-metacognitive ability. In a separate condition, participants performed an identical task with only a Type-1 response followed by a Type-2 response given on a 4-point scale. We found that the two conditions produced equivalent results such that the combination of a binary Type-2 and a binary Type-3 responses acts equivalently to a 4-point Type 2 response. Critically, while Type-2 evaluations were subject to metacognitive noise, Type-3 judgments were made at no additional cost. These results suggest that it is unlikely that there is a genuine distinction between Type-2 and Type-3 systems (metacognition and meta-metacognition) in perceptual decision-making and, instead, a single system can produce both Type-2 and Type-3 ratings. This conclusion raises the question as to whether there is also no clear dividing line between Type-1 and Type-2 systems (cognition and metacognition) in the context of perception.