What "perceptual presence" actually refers to
Perceptual presence is the felt sense that something is really there in front of you, rather than merely thought about or imagined. A predictive processing account of sensorimotor contingencies tries to explain that feeling mechanically: the brain is constantly generating expectations about how the sensory input will change as the body moves, and presence is tied to how well those expectations hold up [1][2]. In ordinary terms, seeing a cup as solid and "out there" depends on implicitly knowing what would happen to the view if you reached for it or walked around it.
Synesthesia — where one kind of input, such as a letter or a sound, reliably triggers an extra experience such as a color — is interesting here because it lets researchers ask why some experiences carry that solid, external feel and others do not. If presence comes from sensorimotor expectations, then a synesthetic experience with no corresponding action-contingent expectations should feel less present, and one that is coupled to such expectations should feel more present [1][2]. That is the core of the predictive answer.
Why expectations about movement would create or remove presence
The proposed mechanism is counterfactual: presence depends not on the current input alone but on the brain's implicit predictions about what the input would be under different actions. A predictive processing theory of sensorimotor contingencies uses exactly this counterfactual structure to explain the puzzle of perceptual presence and its absence in synesthesia [1]. The idea is that when the predicted consequences of moving and looking are available and consistent, the experience is tagged as a real, external object; when they are not, the experience is tagged as something else — imagined, projected, or merely associated.
A phenomenological analysis of chromesthesia (sound-triggered color experience) develops a related view, describing synesthetic experience as dynamic sense-making built on sensorimotor contingencies rather than as a static extra sensation [4]. On this account, the synesthetic experience is shaped by ongoing interaction and anticipation, which is why it can vary in how "out there" it feels. This is presented as a theoretical interpretation, not a demonstrated cause.
Why some synesthetic experiences feel present and others do not
The predictive framework is attractive because it treats presence as a matter of degree rather than an all-or-nothing property. Experiences that are tightly coupled to action-contingent expectations should feel more present; experiences that are decoupled from them should feel less so, and the same account is applied to both the presence and the absence of perceptual presence in synesthesia [1][2]. This lets the theory address the everyday observation that synesthetic colors, for instance, can feel either like genuine external properties or like something more internal and associative.
Work connecting enactivist and cognitivist perspectives adds a further angle: synesthetic affects are discussed as part of how a self is constituted through sensorimotor contingencies, suggesting that the felt quality of synesthetic experience may be bound up with the person's ongoing sense of agency and embodiment [3]. That is a broader proposal about selfhood, and it is offered as a way of integrating frameworks rather than as a tested explanation of presence.
How firm is this answer?
The honest answer is that predictive accounts offer a coherent and widely discussed explanation, but the support here is theoretical. The papers describe the framework and apply it to synesthesia; they do not report experiments that manipulate sensorimotor contingencies and measure presence in synesthetes [1][2][4]. So the account should be read as a promising explanatory proposal — one that makes sense of why presence and its absence could both occur — rather than as an established causal finding.
There is also disagreement about how far the framework should be pushed. The enactivist–cognitivist discussion suggests that predictive processing and sensorimotor contingencies may need to be combined with other perspectives to capture selfhood and synesthetic affect, implying that a purely predictive account may be incomplete [3]. For a general reader, the practical takeaway is that the predictive story is the leading way researchers currently frame the question, while the detailed empirical work of testing it in synesthesia remains open.
Sources used in this answer
'Phenomenology'is Blue: The Synaesthetic Dynamics of Being-in-the-World
Presents a predictive processing theory of sensorimotor contingencies as an explanation of the puzzle of perceptual presence and its absence in synesthesia.
The Predictive Processing Account of Infant Colour Vision Development on Generative Models
Applies a predictive processing theory of sensorimotor contingencies to perceptual phenomena, including the absence of perceptual presence in synesthesia.
Understanding and Reverse-Engineering Selfhood Requires Navigating a Course Through Both Enactivist and Cognitivist Perspectives
Argues that understanding selfhood requires integrating enactivist and cognitivist perspectives, drawing on predictive processing and sensorimotor contingencies and touching on synesthetic affects.
Phenomenological Analysis of Chromaesthesia as Pre-Representational Dynamic Sense-Making
Offers a phenomenological account of chromesthesia as pre-representational dynamic sense-making shaped by sensorimotor contingencies and their bearing on perceptual presence.