I want to thank my supervisors Joost and Peter for their guidance and trust in what was an exciting Master’s project for me. Thanks to Steve for his valuable feedback as well as computational and theoretical know-how.

...We show that this effect becomes stronger in both samples when we included participants that we initially excluded due to being minimally affected by sensory input.

Finally, we related the distinct effects of presence and content cues to hallucination-like perception. While we initially found a relation between hallucination-proneness and the effect of presence priors, it did not replicate in a second sample...

Surprisingly, we also found higher sensitivity to sensory input following absence cues than presence cues and speculate about how an asymmetry between gathering evidence in favour of stimulus presence and absence may account for this result.

Presence cues and valid content cues independently affected participants’ confidence in having seen a grating. We replicated these effects and reproduced them in simulations using a post-hoc adapted version of the higher-order state space (HOSS) model.

This moderating role of presence cues on content cues was also observed when participants falsely perceived a grating with high confidence even when none was actually displayed.

As expected, participants’ orientation responses were biased towards the content cue. Interestingly though, this bias was scaled by the accompanying presence cue so that stronger content cue effects were found if paired with a presence than with an absence cue.

We asked participants to judge both the presence and content (orientation) of noisy grating stimuli while preceding compound cues predicted the likelihood of both overall grating appearance as well as its orientation.

We investigated how expectations of presence and content combine to shape visual perception and show that expectations about stimulus presence act as a volume knob for the effect of content expectations on low-level perception.