Me, Myself, and Therefore “I”
Can you imagine not recognizing your arm as your own? Or feeling your body movements as alien? It’s not easy. We are completely used to feeling our body, thoughts, and actions as our own. We assume this to be so. The “I” in “I reached for the coffee cup” tells people that it is you who performed the action. And it is the “me” in “…and it got spilled all over me” proves that the hand who reached and got spilled is conceived as pertaining to you as well. There are two different senses of “mineness”; first, owning your own body is knowing that your limbs are part of you, that when moving you are the one who is moving; and second, owning your actions is knowing that you initiated and control an action or a particular movement. It is you the one who moves.
We could also see it as “me as an object” vs. “me as a subject”. In one case, I feel my body and limbs, my thoughts, and the ongoing narratives in my head as mine, I attribute them to me, and when perceiving these entities as a part of me I am sensing myself. We will call this one “ownership”. On the other, I experience my movements and my actions as mine or as coming from me, my will, my control, and my intentions. I perform and execute them, I am the source. This one is called “agency”. So: ownership is the feeling of your body and thoughts as yours and agency is the feeling of authorship of your actions. Why do we differentiate them if they normally come hand in hand? Because some neurological conditions have revealed them as separate and some experiments have isolated them to reveal more about how they work.
Let’s talk first about a funny experimental paradigm called the “rubber hand illusion”.
The trick is that although it is visually clear that the rubber hand is not his hand (it is clearly a separate object), what is essentially manipulated is the participant’s proprioception and tactile sensations. Both hands are lying on the table to elicit similar proprioception (perception or awareness of the position of the hand) and receive the same tactile stimulation (soft brushes). So, the information the body of the participant is collecting is the same as if the rubber hand was his, therefore, the sense of ownership emerges to the extent that the participant not only reacts to the predicted pain of the hammer blow, but he experiences the correspondent stress and horrible fear as he was the one about to be hit. We can deduce it from his terrified facial expression after the blow.
Okay. We can trick our brains into switching the ownership of a limb. But can the sense of ownership fail and one not recognize one’s own body? Yes. Two clinical conditions reveal different failure possibilities of this mechanism. First, the body can sense ownership of a limb that is not there. This is known as the phantom limb syndrome and it is well known because it is surprisingly frequent in patients after limb removal interventions: more than half of them will experience “phantom” sensations in the removed limb after the surgery. The person who has a limb removed often declares feeling it as if it were still there, moving and feeling sensations of temperature, texture, pressure, vibrations, and sometimes leading to pain. Can you imagine feeling a part of your body that no longer exists? Feeling pain in an unexisting limb? Imagine the challenge of treating the pain of an invisible hand.
A more “spooky” syndrome is the one called alien limb syndrome, in which a person fails to recognize a limb of hers as hers, sometimes declaring a feeling of discomfort by the fact of having it attached to the body. The alien limb — most frequently a hand — will often move “on its own”, anarchically and nonsensically or purposefully and performing organized action, in all cases with a notorious lack of agency or feeling of “I didn’t do that!” expressed by the patients. Alien limbs imply a failure of ownership, agency, or both at the same time. Can you imagine having a hand that behaves “on its own”? Which goes anarchic without you being able to control it? Clearly, the hand is still a part of you and is controlled by your internal bodily mechanisms. So what is missing? The feeling that you are the source of what it does.
How can these two syndromes be explained? If it is possible to feel ownership of an unexisting limb (phantom limb syndrome) and to lack ownership and agency of a limb that is in fact ours (alien limb), then there must be some kind of failure of a mechanism, one that normally connects our bodies to our subjective feelings in a way that goes completely unnoticed. This mechanism underlying self-awareness is believed to be a prediction mechanism. Our brains are constantly predicting the state and movements of our bodies and things in the world. In the rubber hand illusion, predictions are artificially evoked by the visual input of the rubber hand and matched by the sensations of the brush to the point in which a sense of ownership emerges. The brain is saying something like: “if it feels like you, then it must be you!” And the brain knows what feels like to be “you” thanks to prediction: a soothing brush against your skin would result in a brushy feeling here and there, there is a “brushy” feeling here and there, therefore, the rubber hand is your hand. But, this is just teasing your brain’s predictions. Imagine what can happen if predictions fail to be sent. Self-attribution might not arise because there is no prediction to match for the brain to conclude “I am me”. This is what is hypothesized in the clinical cases just described.
Prediction models are a promising direction in explaining many of the failures in ownership and agency-related syndromes. Experiments such as the rubber hand illusion and the syndromes described reveal interferences in a mechanism. If it weren’t for these cases of interference we would have never thought of an existing mechanism because when functioning normally they go completely unnoticed (has anyone questioned the ownership of her limbs?). What is most important is that it reveals that neither the sense of ownership nor the sense of agency are a given! It teases one of our most basic intuitions about ourselves: that self-experience, the experience of a self who is, exists, thinks, and acts, is not primitive, is not ontologically substantial, this means, that it is not something that exists in and within itself. In other words, we are not a primitive “I” which happens to have a body.
Ownership and agency are the results of brain-body mechanisms. Instead of thinking of our self as an observing and thinking entity situated inside our heads or as being a body-commander, we must think of it in terms of the functioning of our brain-body system. The self is not a thing but rather the result of a process. Supported by neuroscientific research, it is a property to be understood in the context of our brain-body system as a whole.
