How does seeing and feeling the same stroke create a sense of ownership?
The core demonstration is the rubber hand illusion: a visible fake hand is stroked in synchrony with the viewer's unseen real hand, and the fake hand is then felt as one's own [4]. The brain is not simply reading a fixed map of touch and body position; it builds a representation of the body by interpreting and integrating inputs across sensory modalities [4]. In other words, ownership arises when what you see and what you feel line up closely enough in time and place.
The tactile input itself matters, not just its timing. In the rubber hand illusion, the velocity of the touch modulates how strongly the fake hand is experienced as part of one's body [2]. That suggests the integration is sensitive to the quality of the touch signal, not merely to whether a stroke occurred. The same paper frames this as exteroceptive, multisensory integration acting on body ownership [2], which is a reminder that the boundary between body-ownership integration and exteroceptive integration is not a clean wall.
Does the illusion change how the senses themselves perform?
Yes, and in opposite directions. During the rubber hand illusion, tactile detection thresholds decrease while visual detection thresholds increase [5]. In plain terms, people become a little more sensitive to touch and a little less sensitive to vision after the illusion takes hold. This is described as a body-ownership-dependent, diametrical modulation of tactile and visual perceptual thresholds [5].
That pattern is useful for distinguishing body ownership from exteroceptive illusions. An exteroceptive illusion would be expected to alter how you perceive an external object or event; here the measured shift is tied to the ownership state itself, with touch sharpened and vision blunted [5]. The predictive coding framing in that study treats the illusion as a recalibration of how much weight the brain gives to each sense [5], which is a mechanism proposal rather than a proven cause.
When does the illusion depend on where you view the body from, and when does it build up?
Viewpoint matters. Using a virtual leg illusion, researchers tested how visuo-spatial viewpoint affects visuo-tactile integration and the sense of illusory ownership, illusory touch, and illusion of motor control [1]. The study was designed around body ownership rather than exteroceptive illusions [1], so it speaks to how the spatial frame of the seen body shapes integration, not to how external-object illusions work.
Timing matters too. In a virtual-reality full-body setup, researchers tracked the onset of full-body ownership and vicarious touch sensations, and found that these sensations can be structured by visual information even in a purely visual context without tactile feedback [3]. That is a striking contrast with the rubber hand illusion, where synchronous touch is central [4]. It suggests body ownership can be driven by vision alone under some full-body conditions, while the classic hand illusion depends on touch-vision synchrony [3][4].
So how is body-ownership integration different from exteroceptive integration?
The clearest difference supported by these studies is what gets recalibrated. In body ownership illusions, the integration changes the perceived boundary of the self: a fake or virtual body part is assimilated [4], and the perceptual gains of touch and vision shift in opposite directions [5]. Exteroceptive integration, by contrast, is about combining senses to perceive something in the world, and the rubber hand work explicitly frames its tactile-visual effects as exteroceptive multisensory integration acting on body ownership [2].
A second difference is the role of the body's spatial frame. Viewpoint relative to the seen limb changes visuo-tactile integration and illusory ownership in a virtual leg illusion [1], which is a body-specific constraint. And full-body ownership can arise from visual information alone in some virtual settings [3], whereas the hand illusion is classically built on synchronous touch and vision [4]. These studies do not directly test exteroceptive illusions, so the comparison is an inference from what body-ownership experiments manipulate and measure rather than a direct contrast.
Sources used in this answer
Those are your legs: the effect of visuo-spatial viewpoint on visuo-tactile integration and body ownership
In a virtual leg illusion, visuo-spatial viewpoint affects visuo-tactile integration and the strength of illusory ownership, illusory touch, and illusion of motor control.
Bodily pleasure matters: velocity of touch modulates body ownership during the rubber hand illusion
In the rubber hand illusion, the velocity of touch modulates body ownership, showing that tactile stimulus quality shapes tactile-visual integration for ownership.
Temporal dynamics of full-body ownership and vicarious touch sensations as inferred from embodying a virtual avatar
Full-body ownership and vicarious touch sensations can be structured by visual information alone, without tactile feedback, in a virtual-reality setting.
Multisensory Integration in Body Representation
The rubber hand illusion shows that body representation is a construct from integrating inputs across sensory modalities, not a fixed map of touch and proprioception.
Diametrical modulation of tactile and visual perceptual thresholds during the rubber hand illusion: a predictive coding account
During the rubber hand illusion, tactile detection thresholds decrease while visual detection thresholds increase, a body-ownership-dependent diametrical modulation.