Innovation in science and technology will continue to bring much change. But since it is the brain that experiences change, only changing the brain itself can possibly change everything. Changing the human brain is not new, when it is a matter of correcting psychopathology. But whether the usual agents, psychoactive drugs, psychosurgery, electroshock, even what we eat, drink and smoke, can change a brain that is functioning normally (other than for the worse), is not known. However, the novel method of deep brain stimulation (DBS), by which electrodes are inserted into the brain to stimulate precisely specified locations electrically, is already used to correct certain brain disorders (Parkinsonism, Obsessive Compulsive Disorder). Not only are the targeted symptoms often relieved; there have been profound changes in personality, although the prior personality was not abnormal. A patient of lifelong somber disposition may not only be relieved of obsessions, but also shift to a cheerful mood, the instant the current is switched on (and revert to his prior subdued self, the instant it is switched off). The half empty glass temporarily becomes the glass that is half full. The brain seems not entirely to respect our conventional sharp distinction between what is normal and what is not.
The stimulation's immediate effect is shocking. We assume that our gratifyingly complex minds and brains are incrementally shaped by innumerable dynamic and environmental factors. And yet, identical twins adopted apart into sharply contrasting social and economic environments have shown impressive similarities in mood and sense of wellbeing. Genetically determined types of brain organization appear to set the emotional tone; experience modulates it in a positive or negative direction. Stimulating or disrupting neural transmission along a specific neural pathway or reverberating loop may reset the emotional tone, entirely sidestepping the complexities of early experience, stress, misfortune, and let personality float free. The procedure releases a previously unsuspected potential. The human brain is famously plastic. Adjusting key circuitry presumably has wide repercussions throughout the brain's neural network, which settles into a different state. We have yet thoroughly to digest the philosophical implications, but a more unequivocal validation of psychoneural identity theory (the identity of the brain and the mind, different aspects of the same thing) can hardly be imagined.
Certainly, deep brain stimulation is not currently used to render sane people more thoughtful, agreeable, gentle or considerate. Potential adverse neurosurgical side effects aside, ethical considerations prohibit using deep brain stimulation to enhance a brain considered to be normal. But history teaches two lessons: Any technology will tend to become more precise, effective and safer over time, and, anything that can be done, ultimately will be done, philosophical and ethical considerations notwithstanding.
The example of cosmetic plastic surgery is instructive. Reconstructive in its origins, it is increasingly used for cosmetic purposes. I predict the same shift for deep brain stimulation. Cosmetic surgery is used to render people more appealing. In human affairs, appearance is critical. For our hypersocial species, personal appeal opens doors that remain shut to mere competence and intellect. Undoubtedly, cosmetic surgery enhances quality of life, so how can it be denied to anyone? And yet, it is by its very nature deceptive; the operated face is not really the person's face, the operated body not really their body. However, experience teaches that these reservations as to authenticity remain theoretical. The cosmetically adjusted nose, breast, thighs or skin tones become the person's new reality, without significant social backlash. Even face transplants are now feasible. We read so much into a face—but what if it is not the person's "real" face? Does anyone care, or even remember the previous appearance? So it will be with neurocosmetics.
And yet, is it not more deeply disturbing to tinker with the brain itself, than to adjust one's body to one's liking? It is. However, the mind-body distinction has become somewhat blurred of late. Evidence accumulates as to the embodiment of cognition and emotion, and at the least, there is influential feedback between the two domains. Considerations that will be raised by cosmetic deep brain stimulation are already in play, in a minor key, with cosmetic surgery.
Deep brain stimulation seems not to enhance intellect, but intellect is no high road to success. "Social intelligence" is of prime importance, and it is a byproduct of personality. In some form, deep brain stimulation will be used to modify personality so as to optimize professional and social opportunity, within my lifetime. Ethicists will deplore this, and so they should. But it will happen nonetheless, and it will change how humans experience the world and how they relate to each other in as yet unimagined ways.
Consider an arms race in affability, a competition based not on concealing real feelings, but on feelings engineered to be real. Consider a society of homogenized good will, making regular visits to the DBS provider who advertises superior electrode placement? Switching a personality on and then off, when it becomes boring? Alternating personalities: Dr. Accumbens and Mr. Insula (friendly and disgusted respectively)? Tracking fashion trends in personality? Coordinating personalities for special events? Demanding personalities such as emerge on drugs (e.g. cocaine), or in psychopathologies (e.g. hypomania)? Regardless, the beneficiaries of deep brain stimulation will experience life quite differently. Employment opportunities for yet more ethicists and more philosophers!
We take ourselves to be durable minds in stable bodies. But this reassuring self-concept will turn out to be yet another of our so human egocentric delusions. Do we, strictly speaking, own stable identities? When it sinks in that the continuity of our experience of the world and our self is at the whim of an electrical current, then our fantasies of permanence will have yielded to the reality of our fragile and ephemeral identities.