5 Conclusion

In a set of six experiments, we sought to test the proposal that a metacognitive asymmetry between the representation of stimulus presence and absence is one instance of a more general asymmetry between the representation of default states and default-violating surprises. Our findings provide evidence against this idea. A metacognitive asymmetry was not observed in near-threshold discrimination between stimulus pairs that differ in their alignment with default expectations. This was the case even in pairs that showed substantial asymmetries in response time and overall confidence levels. Results from our pre-registered set of analyses are most consistent with a narrow interpretation of the presence/absence metacognitive asymmetry in visual detection, that is limited to concrete, spatially localized presences. Furthermore, a metacognitive asymmetry between Cs and Os in the opposite direction to what is observed in visual search indicates that different cognitive and perceptual mechanisms underlie these two apparently similar phenomena.