Life is dream. Sobre un ensayo de presencia, conciencia y Realidad Virtual

La lectura y discusión sobre estudios acerca de la conciencia en el marco de la neurociencia han ocupado mi tiempo en los últimos meses. En el marco de una asignatura que cursé hace poco con el gran Simon Penny , me metí de lleno en teorías sobre embodied cognition y disfruté a más no poder los textos de Ed Hutchins (os recomiendo “Cognition in the Wild“). Así las cosas, escribí este ensayito esbozando algunas ideas que van desde el concepto de presencia en el marco de entornos inmersivos hasta la posibilidad de explorar a través de éstos aspectos de la conciencia y sobre todo de la percepción. Quizás a alguno le interese…..

Life is dream. Towards a synthetic experience of consciousness

“The body is our general medium for having a world”
Hubert L. Dreyfus
The Current Relevance of Merleau-Ponty’s Phenomenology of Embodiment, 1996

While some researchers in the field of neuroscience try to foster the understanding of consciousness intending to find its neural correlate using fMRI technologies (Ramachandran, Laureys) or classical conditioning procedures on patients diagnosed within the vegetative state (Bekinschtein, et al. 2009; Laureys), others seem to have discovered that Virtual Reality might be a “bodily-centered” way to effectively assess similar issues (Slater, Sanchez-Vives, IJsselsteijn).
This essay proposes that even though it might be too soon to claim that presence serves as a metaphor for a new theory of consciousness, if embraced by neuroscience, it could lead to the emancipation from the cognitivist paradigm.

Presence, consciousness, embedded, embodied, virtual reality

Copyright July 7th, 2011 Universitat Pompeu Fabra, Barcelona

The assessment of consciousness appears to be a pressing issue in neuroscience. As if it was the philosopher´s stone, unveiling its internal structure and mechanisms would bring to light the complexity of human essence.While some researchers in the field of neuroscience try to foster the understanding of consciousness intending to find its neural correlate using fMRI technologies (Ramachandran, Laureys) or classical conditioning procedures on patients diagnosed within the vegetative state (Bekinschtein, et al. 2009; Laureys), others seem to have discovered that Virtual Reality might be a “bodily-centered” way to effectively asses similar issues (Slater, Sanchez-Vives, IJsselsteijn).In this essay I argue that even though it might be too soon to claim that consciousness could be assessed through presence, there is an interesting statement in the proposal of studying perception through means of more bodily experiences such us those provided by immersive environments, avoiding craneo-centric approaches that leave the body and environment out of the problem.
During the last decade, Virtual Reality technology has been deployed in neuro-psychological research as a way to understand how human beings react when immersed in a simulated environment where controlled stimuli can be induced. VR is being used, for example, to treat subjects suffering from phobias (arachnofobia, acrophobia, agoraphobia, etc) or post-traumatic stress disorders. However, for these treatments to be effective, patients need to report a high level of “presence” within the virtual environment (VE).The most common definition of presence refers to the phenomenon of “being there, in the mediated environment” (IJsselsteijn, et al; 2000), behaving and feeling as if we are in the virtual world created by computer displays. In a virtual environment, from a cognitive point of view, the user knows that there is nothing there, but, both consciously and unconsciously, s/he responds as if there is. This paradox, frequent in virtual reality laboratories, lays at the root of the concept of presence, and has a relationship with concepts studied by neuroscientists ranging from perception to consciousness.
However, it seems like a technocratic trick to pretend that presence is something new brought to light by VR. When we watch a movie and cry, laugh or experience fear along with the characters, we can claim being completely “present” within the narrative. If any researcher asked us to fill in a questionnaire or measured our physiological response, s/he would probably acquire the same data that is being gathered during experiments within VE.
Therefore, it is important to clarify that presence is not an exclusive phenomena of VR. Virtual Reality is just a tool, like a book or a movie, with the only difference that it intends to create a context where users can interact through all the senses, considering that the cognitive experience is embedded and embodied.This “all senses immersion” provided by VR has brought along the necessity for a more complete definition of presence. Some new approaches have moved on to a more complex concept based on the understanding of reality not as a mental construction but as bodily interactive experience where presence is “…tantamount to successfully supported action in the environment”. The idea is that reality is formed through actions, rather than through mental filters and that “…the reality of experience is defined relative to functionality, rather than to appearances”. The key to this approach is that the sense of ‘being there’ in a VE is grounded on the ability to ‘do’ there. These ideas have been expressed in other body-centred approaches, in which it is argued that a close match between kinaesthetic proprioception and the stream of sensory data is essential” (Slater, Sanchez-Vives, 2005).

Slater and Sanchez-Vives translate this last concept into a technical issue: when immersed in a VE, the user must see in a first person perspective a representation of its own body which movements will be followed in real-time by the visual stream in the 3D environment. Proprioception and sensori-motor contingencies are taken in consideration as fundamental elements within this approach.



In a VE there are perceptual and technical features that might allow the user to feel presence or not achieve such state. Different research found out that display parameters (the graphics frame rate), the display of dynamic shadows, auditory feedback and spartialized sound, the combination of visual and haptic feedback, a complete virtual body (and the simulation of its real movements) representation may be key aspects in the generation of the feeling of presence. (Slater, 2010; Sanchez-Vives, 2005)IJsselsteijn classifies these factors in four groups:
  1. The extent and fidelity of sensory information: The quantity of useful and salient sensory information presented in a consistent manner to the appropriate senses of the user.
  2. The match between sensors and the display: The sensori-motor contingencies, i.e. the mapping between the user’s actions and the perceptible spatio-temporal effects of those actions.
  3. Content factors: A broad category including the objects, actors, and events represented. The ability of the user to interact with the content and modify it; the user’s representation or virtual body in the VE, and the autonomy of the environment (elements have autonomous behaviors). Also important are the nature of the potential task to be performed, as well as the meaningfulness of the content/narrative to create engagement.
  4. User characteristics have not been given much attention so far, which means taking into account issues such us the user’s perceptual capacities, cognitive and motor abilities, previous experience with VE, expectations towards mediated experiences, and willingness to omit disbelief. Also, allocating sufficient attentional resources within the VE has been suggested to be an important component of presence. Sex and age of the users might be significant as well. In addition, as proposed by Huang and Alessi (1999) mental health conditions such as depression, anxiety, or psychotic disorders, are likely to affect the sense of presence, since they are known to alter how people experience the world around them.
Within a scientific investigation, the possibility to modify the above mentioned VR minimal cues in VE gives researchers the capacity to experiment with perception and awareness. They can activate, deactivate or change the stimuli that the immersed user is receiving and gather information about his/her behavior and perception. This raises another complex issue within research concerning the methods and techniques implemented to measure the level of presence a user is experiencing.
In order to identify and test which parameters have an effect on presence, a reliable means of measuring presence is required. Current means being deployed can be divided into two broad categories: subjective measures and objective corroborative measures. Because presence is a subjective experience, so far the most direct way of assessment has been through questionnaires. Participants carry out some task within a virtual environment, and then after their experience they answer a questionnaire (generally Likert-type scale). Questionnaire based presence assessment methods have been shown to be unstable since prior information can change the results. It has also been suggested that typical questionnaires are not capable of discriminating between presence in a VE and physical reality. As Sanchez-Vives (2005) states: “The use of questionnaires has been challenged through the observation that they cannot avoid a methodological circularity – that the very asking of questions about ‘presence’ may bring into being, post-hoc, the phenomenon that the questionnaire is supposed to be measuring”.
A second method for measuring presence is behavioral. Objective measures, such as postural, physiological or social responses to media, can be used to corroborate subjective measures, as a way of overcoming some of their stated limitations. If participants within a VE behave as if they were in an equivalent real environment then this would be considered as a sign of presence. Behavioral measures tend to require the introduction of features into the environment that would cause a bodily response. A particular specialisation of the behavioral approach is to use physiological measures, such as those obtained through ECG (electrocardiogram) recordings or EDA (electrodermal activity). If the normal response of a subject within physical reality to a particular situation is known and s/he exhibits the same response within a VE, then this is a sign of presence.
AS A CONCLUSION: An illusionary context for consciousness
Slater and Sanchez-Vives believe that neuroscience should become more interested in presence research, so far quite exclusive of engineering sciences, because presence “may be regarded as consciousness within a restricted domain” (2004). Since presence is based on the transportation of consciousness into an alternative, virtual reality, it could be said that presence is consciousness within the VE (Slater, 2010).
In addition, investigations on presence aim to answer key questions that could help neuroscience comprehend issues probably related to consciousness: is perception a bottom-up or top-down process? How much of what we perceive is conditioned by physical reality? which are those areas in the brain involved with spatial navigation? Each one of these questions could find an answer through experimentation within the realm of VR.
Presence research within neuroscience might bring new perspectives and overshadow the traditional cognitivist approach for which consciousness occurs isolated in the skull, as a result of the integration of stimuli in correlated structures of the brain (Laureys, 2010). When researchers focus exclusively in fMRI studies, they are inevitably proposing that mind is separated from body and environment , and perception is a channel by which it absorbs external information in the form of stimuli. As Haugeland (1998) argues, this could be described as straightforward Cartesian Dualism, where there is a complete separation of mind and body, through the notion that the mind could exist independently, without a body, retaining all its characteristics. This contradicts the “enactive approach” proposed by Varela, Thomson and Rosch (1991) that suggests that the mind is embodied in our entire organism and embedded in the world, hence it is not reducible to structures confined within the skull.
Herbet Simon´s “ant parable”, illustrated by Haugeland, might be an interesting metaphor to deconstruct the above paradox. He describes an ant creating a complex path in the sand of the beach while travelling around avoiding dunes. From a point of view rooted in dualism and representationalism, the ant is a simple interface that inputs the information in the beach in an inner symbolic representation (the world information is “transduced” into a narrow-band signal of simple data). Then its brain calculates the resulting behavior and sends this signal to his body to perform an action.However, the parable could be understood in the opposite way: if the sand holds the big part of the complexity, both the ant and the beach are equally parts of the same complex system. The same conclusion could be applied to the research on presence using VR. Through it, consciousness could be considered as a process that occurs among the complexity of the embodied mind, a “bodily self” embedded in a context, being here the VE. Some could claim that this would be a synthetic consciousness but that argument would need to explain what reality is and therefore would run the risk of falling into a discourse loop.Within a VE researchers are able to study cognition and perception as a process that cannot ignore the holly trinity mind-body-environment. If the mind is embodied and embedded then studies of consciousness within neuroscience have a chance to avoid the corset of dualism proposed by the cognitivist and representational paradigm. However, if there is any chance that consciousness can be scientifically measured, then a lot of work remains to be done designing better techniques that do not rely on explicit reports.

I believe, so far, state of the art research on presence can lead to reviling findings in the field of human perception, even though it might be too soon to propose that it will give birth to a new theory of consciousness. Nevertheless, unless neuroscience shifts is approach, Chalmes` prophecy written in the Scientific American in 1997 might occur: “Consciousness, the subjective experience of an inner self, could be a phenomenon forever beyond the reach of neuroscience. Even a detailed knowledge of the brain’s workings and the neural correlates of consciousness may fail to explain how or why human beings have self-aware minds”.



Bekinschtein, T., Shalom, E., Forcato, C., Herrera, M., Coleman, M., Manes, F., Sigman, M. Classical conditioning in the vegetative and minimally conscious state. Nature Neuroscience 12, 1343 – 1349 (2009)

Haugeland, J. (1998). Mind embodied and embedded. In Haugeland, J. (Ed.). Having Thought. Cambridge, MA: Harvard University Press.

Huang, M.P. & Alessi, N.E. Mental health implications for presence. CyberPsychology and Behavior 2, 15-18. (1999).

Laureys, S. The neural correlate of (un)awareness: lessons from the vegetative state. TRENDS in Cognitive Sciences, Vol.9 No.12 ( 2005)

Sanchez-Vives, M.V., Slater, M. From presence to consciousness through virtual reality. Nature Reviews Neuroscience 6, 332-339 (April 2005)

Sanchez-Vives, M.V., Slater, M. From Presence Towards Consciousness (Jan 2004)

Slater, M., Spanlang B., Corominas, D. Simulating virtual environments within VE as the basis for a psychophysics of presence. ACM Transactions on Graphics (TOG) – Proceedings of ACM SIGGRAPH

Thompson, E. (2005). Sensorimotor subjectivity and the enactive approach to experience. Phenomenology and the Cognitive Sciences, 4(4), 407–427



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