IEEE Technology and Society Magazine - June 2015 - 67

and start over again. He's asking for a divorce! Can you
please talk to him? Does it have something to do with
the surgery? I don't know what to do!"
Steven agrees to come to the neurosurgeon's office.
Upon entering, it is apparent that his demeanor has
changed. While once he was quiet and unassuming,
now he exudes confidence and even arrogance. "I feel
so much better, Doc! Call me 'Steve' by the way. All those
obsessions and crazy things I did... that tension and pain
that made me do them, it's all gone. I can't thank you
enough. You changed my life."
The neurosurgeon presses Steven about why he
wants to leave his wife to which he replies that he does
not really love her and that he wants to start a new life.
When reminded of the children that he wanted to have
with her, he grows impatient and is dismissive, changing
the subject to the weather.
This scenario raises two urgent questions: "Has DBS
fundamentally changed who Steven is as a person?"
and "Why or why not?" Given what is known about the
case, there is no obvious answer to these questions. In
fact, there is a multitude of equally valid interpretations.
The next section presents three philosophically distinct
methods for interpreting this case. While they do not
represent an exhaustive list of interpretation strategies
by any means, they will serve to magnify the inherent
paradoxes of Steven's situation.

Examination of the Hypothetical Case
The above case is intended to highlight how different conceptions of human identity yield different interpretations of
the effect of DBS on the subject. The three models of identity that I will analyze the case with are 1) a clinical model,
2) a Lockean model, and 3) a core periphery model.

Clinical Model
Looking at this case in purely medical terms, it would
be hard to characterize the outcome of Steven's treatment with DBS as anything less than a complete success, especially given the parameters for success and
failure laid out in the traditional informed consent
process. First, the symptoms that characterized his
OCD have completely subsided, which was the primary
intent of the procedure from a clinical standpoint. Second, the patient experienced none of the complications of bodily harm that were initially described in the
informed consent process. In other words, there was
no significant blood loss, infection, device failure, or
functional neurological deficit (e.g., paralysis, loss of
sensory function, pain, or loss of speech). Finally, the
patient appears to be delighted with the outcome. Clinically, this appears to be a successful procedure and the
apparent change in the patient's goals, while curious,
are a non-issue.
june 2015

∕

Lockean Model
The 17th century English philosopher John Locke argued
that the essence of an individual's identity, his or her
sense of self, is seated in that individual's memories [7].
In proposing this model of identity, Locke was attempting
to explain why an individual who performed an action,
such as a crime, at one point in time could be held
responsible for it at a second point in time. He proposed

The core periphery model
emphasizes the role of a patient's
values and priorities in determining
whether a patient's identity has
changed significantly.

that it was the continuity of consciousness (that consciousness could be extended backwards to the event in
the form of memory) which made one responsible.
For example, imagine a thief breaking into a house and,
during his attempt at escape, he kills one of two occupants
while the other looks on. Now, for the sake of argument,
suppose upon waking in the following morning the memories of the surviving occupant and those of the thief are
switched. Let us call the new arrangement of memories
and bodies thief' and occupant' to signify the occupant's
memories in the thief's body and the thief's memory in the
occupant's body respectively. Continuing the thought experiment, imagine the police follow the forensic evidence and
catch the thief'. Would it be just to punish him? All evidence
points to the thief' as the culprit (fingerprints, DNA, security
footage, etc.); however, one must recognize that the thief'
would go to the gallows with the memory of watching the
murder of his friend burning in his head. Locke would argue
that our intuition is that the thief' should go free and the
occupant' should be found guilty of the murder. This result
suggests responsibility intuitively follows the continuity of
consciousness in the form of memory and is not necessarily tied to the physical body of the individual.
How is one to interpret the effect on Steven through the
lens of this model of identity? Given that he has not had a
drastic change to his memory, he still recalls his wife and
friends - he just chooses to no longer associate with them,
one can argue that DBS has had no effect on his identity.
Therefore, we are left to see the alteration in his personality as a neutral feature of DBS. Perhaps Steven was "really"
a person who resented his wife and friends all along and

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