Hypothesis Investigation – overview

Hypothesis investigation (short for “hypothesis-based investigation”) is simply attempting to determine “what is going on” in some situation by assessing various hypotheses or “guesses”.  The goal is to determine which hypothesis is most likely to be true. 

Hypothesis investigation can concern

• Factual situations – e.g. what are current Saudi oil reserves?
• Causes – e.g. what killed the dinosaurs?
• Functions or roles – e.g. what was the Antikythera mechanism for?
• Future events – e.g. how will the economy be affected by Peak Oil?
• States of mind – e.g. what are the enemy planning to do?
• Perpetrators – e.g. Who murdered Professor Plum?

Most investigation is to some extent hypothesis-based.  The exception is situations where the outcome is pre-determined in some way (e.g., a political show trial) and the point of the investigation is simply to amass evidence supporting that determination. 

A related, though subtly different notion is that of “hypothesis driven investigation” (Rasiel, 1999), in which a single hypothesis is selected relatively early in the process, and most effort is then devoted to substantiating this hypothesis.   It is hypothesis-based investigation with all attention focused on one guess, at least while not forced to reject it and consider another. 

Hypothesis investigation is comprised of three main activities

• Hypothesis generation – coming up with hypotheses;
• Hypothesis evaluation – assessing relative plausibility of hypotheses given the available evidence; and
• Hypothesis testing – seeking further evidence.

Traps in Hypothesis Investigation

Hypothesis investigation fails, at its simplest, when we get (take as true) the wrong hypothesis.  This can have dismal consequences if costly actions are then taken.  Hypothesis investigation also fails when

• there is misplaced or excessive confidence in a hypothesis (even if it happens to be correct);
•  no conclusion is reached, when more careful investigation might have revealed that one hypothesis was most plausible. 

There are three main traps leading to these failures.

Tunnel vision

Not considering the full range of reasonable hypotheses.   Lots of effort is put into investigating one or a few hypotheses, usually obvious ones, while other possibilities are not considered at all.  All too often one of those others is in fact the right one. 

Abusing the evidence

Here the evidence already at hand is not evaluated properly, leading to erroneous assessments of the plausibility of hypotheses.

A particular item of evidence might be regarded as stronger or more significant than it really is, especially if it appears to support your preferred hypothesis.  Conversely, a “negative” piece of evidence – one that directly undercuts your preferred hypothesis, or appears to strongly support another – is regarded as weak or worthless.    

Further, the whole body of evidence bearing upon a hypothesis might be mis-rated.  A few scraps of dismal evidence might be taken as collectively amounting to a strong case. 

Looking in the wrong places

When seeking additional evidence, you instinctively look for information that in fact is useless or at least not very helpful in terms of helping you determine the truth.

In particular we are prone to “confirmation bias,” which is seeking information that would lend weight to our favoured hypothesis.  We tend to think that by accumulating lots of such supporting evidence, we’re rigorously testing the hypothesis.  But this is a classic mistake. We need to know not only that there’s lots of evidence consistent with our favoured hypothesis, but also that there is evidence inconsistent with alternatives.   You need to seek the right kind of evidence in relation to your whole hypothesis set, rather than just lots of evidence consistent with one hypothesis.  

This can have two unfortunate consequences.  The search may be

• Ineffective – you never find evidnce which could have very strongly ruled one or more hypotheses “in” or “out”. 
• Inefficient – the hypothesis testing process may take much more time and resources than it really should have. 

We fall for these traps because of basic facts of human psychology, hard-wired “features” of our thinking tracing back to our evolutionary origins as hunter-gatherers in small tribal units: 

• We dislike disorder, confusion and uncertainty.  Our brains strive to find the simple pattern that makes sense of a complex or noisy reality. 
• We don’t like changing our minds.  We find it easier to stick with our current opinion than to upend things and take  Further, we have undue preference for hypotheses that are consistent with our general background beliefs, and so don’t force us to question or modify those beliefs.  
• We become emotionally engaged in the issues, and build affection for one hypothesis and loathing for others.   Hypothesis investigation becomes a matter of protecting one’s young rather than culling the pack (Chamberlin, 1965).
• Social pressure.  We become publicly committed to a position, and feel that changing our minds would mean losing face. 

And of course we are frequently under time pressure, exacerbating the above tendencies.    

General Guidelines for Good Hypothesis Investigation

Canvass a wide range of hypotheses

Our natural tendency is to grab hold of the first plausible hypothesis that comes to mind and start shaking it hard.  This should be resisted.  From the outset you should canvass as wide a range of hypotheses as you reasonably can.  It is impossible to canvass all hypotheses and absurd to even try (Maybe 9/11 was the work of the Jasper County Beekeepers!).   But you can and should keep in mind a broad selection of hypotheses, including at least some “long shots.”   In generating this hypothesis set, diversity is at least as important as quantity.

You should continue seeking additional hypotheses throughout the investigation.   Incoming information can suggest interesting new possibilities, but only if you’re in a suitably “suggestible” state of mind.   

Actively investigate multiple hypotheses

At any given time you should keep a number of hypotheses “in play”.   In hypothesis testing, i.e. seeking new information, you should seek information which discriminates which will be “telling” in relation to multiple hypotheses at once. 

Seek disconfirming evidence      

Instead of trying to prove that some hypothesis is correct, you should be trying to prove that it is false.   As philosopher Karl Popper famously observed, the best hypotheses are those that survive numerous attempts at refutation.  

Ideally, you should seek to disconfirm multiple hypotheses at the same.   This can be easier if your hypothesis set is hierarchically organised, allowing you to seek evidence knocking out whole groups of hypotheses at a time.  

Instead of trying to prove that some hypothesis is correct, you should be trying to prove that it is false.   As philosopher Karl Popper famously observed, the best hypotheses are those that survive numerous attempts at refutation.  

Ideally, you should seek to disconfirm multiple hypotheses at the same.   This can be easier if your hypothesis set is hierarchically organised, allowing you to seek evidence knocking out whole groups of hypotheses at a time.  

Structured methodologies.

Some methodologies have been developed to help with hypothesis investigation.  The methodologies have some important advantages over proceeding in an “intuitive” or spontaneous fashion. 

• They are designed to help us avoid the traps, and do so by building in, to some extent, the general guidelines above.
• They provide distinctive external representations which help us organize and comprehend the hypothesis sets and the evidence.   These external representations reduce the cognitive load involved in keeping lots of information related in complex ways in our heads.

Some structured methodologies are:

• Analysis of Competing Hypotheses (Heuer, 1999), designed especially for intelligence analysis
• Hypothesis Mapping
• Root Cause Analysis