Monday, July 13, 2020

Rules of Evidence

Suppose you  go to a family party. Perhaps your nephew, Woodie, graduated from high school. It is a joyous occasion.

Your oldest sister is there with her new boyfriend, Biff. Biff appears to be in distress. You work in the medical profession. Maybe you are an EMT. Maybe you are a nurse.

Your sister tells you that Biff is just suffering some anxiety at meeting so many new people, that he gets panic attacks.

You look at Biff. He is rail thin. Every symptom points to a myocardio infarction, all the way to the bluish lips.

Do you ruin the party?

Slightly different scenario

You are still in the medical profession. You just moved into a new neighborhood. It is summer. One of your new neighbors is having a pool party.

You and your beautiful spouse mosey on over after the party is well underway.

Scanning the crowd with your professional eye, you see a young man who is way more impaired than the hour and potency of the punch indicates. You stroll over.

You see a medical alert necklace on the young man. His date assures you that he is just really drunk. Bending in close, you smell the distinctive, fruity aroma associated with ketoacidosis.

His date assures you it is the smell of the pineapple juice in the punch.

Do you ruin the party?

We run into these situations all the time. If we were Biff or the "drunk" date, we hope the medical person decides to ruin the party.

When do we act on evidence? When do we let it play out without acting?

Rules of Evidence
Humans are very imperfect processors of data.

While the rules or hierarchy of evidence might vary by profession, there are some commonalities.

Following common Rules-of-Evidence tells you when it is time to ruin the party.

Hear-say evidence is always low quality
Your older sister said "Biff gets panic attacks." That is hear-say unless your sister is a psychiatrist or a Ph.D. psychologist and Biff is her patient. And if Biff is her patient, there are rules against her dating him because emotion is pollutes the ability to make meaningful diagnoses and design effective therapies.

You hear the shortness of breath. Biff tells you the pain he is feeling. You can see the color of his lips.

You decide to ruin the party because the evidence you collected first-hand almost always out-weighs second-hand information.

Regarding the pool party. A lot rides on what the medical alert necklace says. I bet it says the "drunk" is diabetic. If you can collect that last bit of information, then you make the party a memorable one rather than a tragic one.

We tend to accept second-hand information when it validates our fears or hopes or sense-of-specialness.

Being the first to scoop information is a very common way of feeding that sense of being special. "Hey, look. I am connected. I was the first to know." Facebook would collapse overnight if members waited until the third of forth report before chiming in.

Bill of Rights
The Sixth Amendment to the US Constitution enunciates our God given right to face those who accuse us.

Anonymous accusers can claim more "knowledge" than they actually have. They can be "false witnesses" and claim to witness events that they heard about second or third or fourth hand. If you were to tot up all the people who claim to have been on the raid that bagged Osama bin Laden, you would have needed a dozen 747s to deliver them all to the compound. Most of them were not there.

Another problem with anonymous witnesses is that we cannot evaluate any "moral hazard" that might bias the witness's testimony. Suppose the witness is an ex-romantic partner and they parted on a sour note. Suppose the witness is a business competitor who stands to benefit if the accused is taken out-of-play?

What if I am my own anonymous witness? Would you expect an unbiased testimony regarding my character? If you knew I was providing my own character reference than you would rightfully discount the testimony.

Pattern Seeking
We are imperfect processors of data. Our brains tend to fail in predictable ways.

For instance, our brains are pattern-seeking. As soon as our brain finds a pattern that comes close to matching the requirements, it stops looking.

Your sister wants to stay at the party. Biff does not like crowds. Your sister's dog pants during thunderstorms. "Biff is having a panic attack". Problem solved.

The "drunks" date doesn't want to make a scene. Being drunk is temporary. Having diabetes is a life-time thing. She WANTS him to be drunk. It fits all the symptoms she is capable of assimilating. Problem solved.

Vivid vs. Boring
Our brains (except for Boris who is half Vulcan and half Cray Super-computer) can process very limited amounts of data at a time. Quick: What is 12,345 + 43,210?

We take out a piece of paper, write down the problem and then ask our self "What is 5+0?" and then chew our way through the problem one step at a time.

We compensate for our limited mental capacity by recursing, that is, following a simple procedure (like sorting) over-and-over until we reach an acceptable solution.

Think of it as combing snarls out of your hair. You take a small hank of hair. You start near the end. You comb out the end 1/2". Then the end 1". Then the end 1-1/2" and so on.

The problem is that the information that is most readily accessible to our mind is the vivid information that we connect with emotionally.

EMOTION is the native operating system of our brain. LOGIC is a foreign system that is emulated in the native system. LOGIC is always slower.

Because our brains process EMOTIONAL data more quickly that LOGICAL data, and because our brains stop working when we reach an OK solution, the EMOTION driven 7/8ths of the brain nearly always finds an OK solution sooner than the LOGICAL side.

The net effect is similar to compound interest. The EMOTIONAL side gets amplified 1.10^n while the LOGICAL side is attenuated 0.9^n where "n" is the number of iterations needed to completely comb out the tangled hair.

Because of EMOTION's ability to dominate decisions and because it is almost impossible to be objective about EMOTION, EMOTION is only used as a tie-breaker.

If you are hiring somebody, sort through the candidates using boring, LOGIC and weed out every candidate who is unlikely to be a good fit. Then, use interviews and EMOTION to pick from the much smaller pool of fully qualified candidates. At that point, you could throw a dart and be sure you would hit a good one.

Looping back to the two vignettes at the beginning of the post
The medical person assessing Biff and the "drunk" is trained to give ZERO credence to everything except the hard evidence.

The fact that others made bad diagnoses before you arrived. The fact they will get angry if you blow-off their assessment. The fact that your wife is giving you the stink-eye as you quarter your way toward the "drunk" like an English Pointer quartering a stubble field searching for a covey of quail...they have zero bearing on the medical facts.

Isn't that the foundation of civilization? We have many people who are trained to be color-blind to emotion and unswerved by empathy so they can do their jobs in the best possible way.

Getting to cases
The twenty-something who objected to "old people" saying "America is the greatest" isn't getting any sense of "special" by accepting that viewpoint. She is not the first to be in-the-know. From the standpoint of a recent college graduate who invested a significant percent of her life-to-date, there is little satisfaction in affirming something that has been "known-and-provable" since 1918.

The same tendency that leads people-with-means to buy a Mercedes when everybody else is driving a BMW or a Maybach when everybody else is driving a Mercedes drives the twenty-something to tout Scotland over the US, for instance.

In one way, it is a good thing that she does not blindly accept Aggie writing, "Hey, I have been in twenty countries in my lifetime and none of them are as good as their tourist propaganda claims. In fact, none of them can hold a candle to the good, old USA"

Another point in her favor is that she accepted first-hand testimony from fellow college students who came from places like Scotland, The Netherlands, Ghana and the like.

On the other hand she clearly accepted the second (or third of fourth-hand) testimony of a T/A who was projecting "I am in the know, the US sucks".

Tangential story
I worked with an engineer I will call Mike. Mike was from Romeo, Michigan. Mike was at a party at a prestigious University in Michigan shortly after he graduated from college.

At the time, the dominant contractor in the Detroit Metro area had a Mediterranean last name. Because the last name was long, his company went by his first and middle name. For the purposes of this story, let's say his company's name was "Don Mario".

The contractor lived in Romeo.

Talk at the party turned to corruption in the construction business. One of the drunk frat boys opined that Don Mario probably won most of his business via kick-backs, bribes and intimidation.

Our intrepid friend from Romeo saw an opportunity to show himself to be a man-of-the-world. "Oh, hell. yah! I am from Romeo and I know ALL ABOUT HIM. You don't know nothing. The stories I could tell you would curl your hair."

There was a young lady at the party. It was a girl he vaguely remembered from high school. She graduated a year behind him. She was cute. She tried to inject "You can't know that. That is not true. Don Mario has to deliver performance to keep getting contracts...."

Our hero hooted her down.

The next morning, after he sobered up and the worst of his hang-over left him he had an epiphany. He grabbed his yearbook just to be sure. The young lady had a very long, very Italian last name; something like Carraracannaberra.

Mike had this cold lump in his gut. He had just spent an appreciable portion of the previous night absolutely disrespecting a multi-millionaire (like $100M) in front of his beloved daughter.

If he had not been so desperate to impress the frat-boys (boys he would never see again), but rather had defended her father using the simplest rules-of-evidence...something Don Mario's daughter had attempted...Mike could have been waking up in her bed and have an inside-track at being Don Mario's son-in-law.

But the need to fit in, the need to be "special" within that ephemeral group was his undoing. He let his emotions drive his bus. And he was an engineer.

Grim prognosis
  • Stories are more vivid than exposition. That is why I rely heavily upon stories to make a point or relay information. People listen to, and remember stories.
  • Face-to-face is more vivid and interactive than video.
  • Video is more interactive than pure audio.
  • Voice is more interactive than the written word.

Vivid data overwhelms even logical minds unless concrete barriers are positioned to partition it away from us.

Voices and stories that honor the knowledge gained by generations of painful experience are being silenced.

Voices and stories and video that are dripping with emotion and fantastical solutions are being promoted on the internet.

Good judgement comes from painful experiences.

Painful experiences come from bad judgement.

The inability of younger people to accept the authority of history and Tradition dooms them (and ultimately us) to avoidable, painful experiences.

And the younger people will wail "I just didn't KNOW!" while their parents will say "We tried to tell you but you would not listen."


  1. What is 5+0?
    And yes, no one wants to know what experience teaches except the experienced.

    1. If you are paranoid, believe people talk in code and believe in "dog whistles", 5+0 is the police.

      If you are writing a blog post and need an example, it is a simple fact of arithmetic all my readers would know.


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