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A typical neuropsychological examination tests a patient’s cognitive function in a variety of domains. Intelligence, memory, attention, spatial skill, planning and organization are the broad categories. In each domain, a number of different tests may be given to cover different aspects of ability. Hundreds of data points result from this kind of assessment, and interpreting this amount of information is the particular skill of the neuropsychologist. Not only is it necessary to determine whether the test scores are within normal limits for the specific circumstances of the patient, overall results are scrutinized for the tell tale arrangements found in brain injuries, diseases and disorders. It is challenging work, especially so when the data do not fall into identifiable patterns.
In the early 1990’s neuropsychologists began to develop methods to determine the validity of test results. When a neuropsychologists tests someone, the instructions include “try your best”. The point of that is to get results that are as accurate a reflection of the patient’s ability as possible. These new methods were developed to identify those situations in which the data did not reflect best effort, and consequently did not give an accurate description of the patient’s level of function.
Now referred to as performance and symptom validity measures, the neuropsychological discipline of behaviour and brain function went on in subsequent years to develop a number of highly reliable methods of evaluating test performance validity. Think of it as methods of data verification. They are the first step in determining if the patient’s test scores are accurate indicators of their ability and can be reliably interpreted. If no to validity, then no to interpretation. Full stop.
Except for the glaring implication that low validity might mean the patient was lying.
In the Canadian parliament, a member may stand up and waffle, evade, duck, weave, dissemble, distract, mislead or outright lie. Just another day in parliament. What a member may never do is call another member a liar. This results in immediate expulsion from the House.
People may indeed mislead or lie, but calling someone a liar is completely unacceptable. With these validity techniques, neuropsychologists were effectively seen as human lie detectors. All hell broke loose. Lawyers in court thundered, Doctor, are you calling my client a liar? As did family members, patients themselves and their physicians. It was hard on psychologists as well. Most health care practicioners had been accustomed to accepting a patient’s report, and their test data, as accurate as a matter of course. Such trust was part of a therapeutic rapport. It seemed disrespectful to question a patient’s presentation. I heard, more than once, the protest: “My patients don’t lie”.
This last protest is noteworthy. Psychologists and neuropsychologists struggled to reconcile firmly held convictions, built up over years of experience, with the emerging studies.
The validation methods were developed in part because there was too many implausible results and not enough data driven explanations. This turned out to be a very important step for neuropsychology. It took some decades of research, but after a while the results were just so overwhelming that testing for effort became a standard of practice.
The whole topic has left me with larger questions about truth and lies. How to understand what has been called personal truth, compared to verifiable facts? Are they the same thing? Given that people lie, and it seems to be a common enough behaviour, when and how does it become a problem?
In the last Substack column, Prediction and Reality, I closed off with the suggestion that an important role for the conscious mind was testing information for reliability and accuracy. After learning, the next step in information processing is to consciously look for proof of some kind. The question is, Can I rely on this information to shape my understanding of the world?
New information can be tested by doing a real world experiment. If successful, the result adds to the store of objective and consensually accepted information. It is real, true, and can be verified by others doing the same experiment. It is the information that leads to structures, science, regulations, the hard and immutable facts we rely on to keep the bridges up.
Another way to test information is subjective. Does the information fit with or challenge one’s personal understanding of the world? The question is, Can that be right? I find that hard (or easy) to believe. Perhaps the new information is readily accepted. It may confirm that the way you saw things was indeed the case all along. I knew it. This test uses one’s own personal predictive model that explains to you how the world functions. This type of test allows you to accept or reject something based on your convictions alone. If there is a subjective sense that the fit might not be good enough, then various options are open. Seek more information, put the matter on hold or argue oneself into accepting something that seemed off.
The testing phase determines if information is accurate enough to rely upon in the future. Truth is a quality of fit for purpose until better information is available, something that builds a more comprehensive world view.
The two ways of evaluating information, in the outer and inner worlds, yield different results. One set of results are accepted as facts or truth. The other set of results is conviction, a personal map of how the world works. Both are taken to represent reality: one witnessed, one felt.
The two versions may clash. As the cheating husband said to the discovering wife: who ya gonna believe, me or your lying eyes? The two versions may also be complementary.
Finding the truth of something involves going over information, perhaps repeatedly, until an integration of observed facts and stored experience emerges that is satisfactory. Objective truth is public, something shared. It is a consensus of agreed upon facts. A personal conviction is also a result of a survey, this time of what is held in one’s own fund of knowledge.
Societies rely on both perspectives on reality to function. Objective truth builds roads, creates vaccines, sets up regulatory models for the qualifications to practice psychology. It is for structures, both concrete and abstract. Subjective conviction is what drives people to do things. It is what they believe in, will sacrifice and work for, what they will fight for. It provides the necessary drive to do hard things.
The behaviour of people, especially in group endeavours, reflects a blend of the two. A shared sense of objective truth alongside personal conviction is involved in actions that affect the wider group. Groups need to trust that they have good information in order to work together. The trust in turn relies on externally verified information. If, anywhere in the chain, someone has told lies or misrepresented the truth, trust can break down.
The effects can be devastating to more than an individual; it can echo through a community. When someone lies, a private act meets the public world of facts. A lie can not just happen. In order to tell a lie, the liar must know where the boundary of truth is. Lies are told to further a personal conviction over the collective benefit. The conviction may be as basic as one’s personal gain is more important than the good of the other. It may be simply believing a lie is good for some reason, however minor, and that this one is tolerable. Lies reflect a conscious decision that the objective truth can be sacrificed for some reason.
An error in fact can be understood and accepted, but a deliberate lie corrodes the trust of recipients. It is a volatile thing, telling a lie. It can remain buried forever or go off at any time. We come to the strange place, such as the parliament, where lying is known to occur, but never acknowledged. Lies are like land mines. Do you want to step there or not?
When revealed, lies can cause anger and confusion to the recipients. Social trust is affected. On a grander scale, any human institution can be compromised. Sometimes, to keep the group or institution going, some level of lying is tolerated. Perhaps it is a question of scale. The boundary is, just don’t lie to me about the important stuff. The problem is that practice gives the miscreants cover. How dare you call me a liar. As human activities go, it is remarkable corrosive. Put one even mildly prolific liar in a group and watch the social cohesion dissolve.
In the end, verifiable truth is more powerful than subjective conviction. We may feel most intensely in the subjective world, but we exist and live in objective reality.
One’s personal convictions are a product of unconscious formulation. We each build our own. Others may share some of these convictions, and it may be discussed amongst the believers, but that does not yet transform it to the realm of tested truth. Yet, although not tested, convictions subjectively feel just like truth. A bond forms when people agree to share a conviction as though it were truth, knowing that bond may be at risk if they were to test the reality of the shared conviction. Those bonds survive solely on trust.
Overt and deliberate lies are different. This is one person’s version of events and they want the other to accept it, for any number of reasons. Perhaps there is an intent to form a personal, shared bond but there may also be some form of consequence. Accept this lie, or else. The problem is that lies run in packs. There is never just one. Once you realize you are being lied to, not once but consistently, the relationship takes on a whole new complexion.
The relationship we have with trust is not at all straightforward. Societies need both personal conviction and objective truth, yet tolerate lies. Lies can erode trust, which is both necessary and fragile. We go to great lengths to protect trust. Some lying might be tolerated, but a breach of trust is more serious.
This is why neuropsychological validation methods had such an impact. They permitted the neuropsychologist to decide if they could trust the test results sufficiently to interpret the data. Neuropsychology had developed a quantification of trust.