Mutual influences between bodily self-consciousness and conscious awareness

C-lab meeting with a presentation by Marta Łukowska (in cooperation with Roy Salomon, Giulia Galli, Javier Bello Ruiz & Olaf Blanke).

The scientific study of consciousness has become a central focus of cognitive neuroscience. Two important aspects of consciousness, have received considerable empirical attention. Bodily self-consciousness, or how the feeling of the self as a unified entity in the body arises from integration of multisensory bodily signals has been studied in healthy and neurological populations. The study of visual consciousness awareness has focused on the cognitive and neural modulators rendering a stimulus aware or unaware. However, there have been few investigations of the interplay between bodily self-consciousness and visual conscious awareness, thus overlooking possible mutual influences between them.

In a set of two studies, using robotics, virtual reality and continuous flash suppression we investigated how visuo-tactile conflicts, which have been shown to modulate bodily self-consciousness, affect visual conscious awareness and how unconscious visuo-tactile conflicts impact bodily self-consciousness. The first study consisted of three experiments, in which we show that: (i) visuo-tactile conflicts break suppression more rapidly than non-conflicting visual tactile stimulation; (ii) this effect is modulated by the presence of a visual body form and (iii) the results are not due to detection or response biases.

In the field of bodily self-consciousness, visuo-tactile conflict has been shown to influence sense of ownership over a limb or even the full body as in the rubber-hand and full-body illusions. Both paradigms introduce visuo-tactile conflict by synchronous stroking of a seen virtual body (part) and the unseen real body (part). It has been suggested that the illusion is due to an erroneous integration of the seen and felt touch. Here we tested if it is possible to manipulate bodily self-consciousness by introducing unconscious visuo-tactile conflicts – with full suppression of visual stimulation from awareness. In two experiments we compared the influence of conscious and unconscious visuo-tactile conflict on bodily self-consciousness in the context of automated full-body illusion procedure. We used both subjective (questionnaire) and objective (body temperature) measures of the illusion. Our results shown that even when the visual stimuli were unaware (according to both objective and subjective criteria) and no visuo-tactile conflict was consciously experienced a full body illusion occurred.

The results of both studies show that visuo-tactile information is integrated without awareness. Thus, visuo-tactile conflicts modulate not only the formation of bodily self-consciousness but also the content of our conscious awareness and even an unconscious visuo-tactile conflict is able to impact bodily self-consciousness. These finding highlight an important link between bodily signals and the experience of the external world in the visual domain.