Check out the register

For at least 80 years people have used the word register.  It is the word used to indicate that some words are commonly used and others are not.  People don't use words for a variety of reasons.  Sometimes people have rather restricted vocabulary banks.  That is usually a function of educational level, but not always.  Sometimes people have limited experience in a lot of different fields while others expose themselves to many different disciplines.   The more limited the experience, the more restricted the vocabulary.  Some people have decided that reading is tedious.  That results in having vocabulary disappear even if they have exposed themselves to words because of the principle, "Use it or lose it."  Reading regularly is a cause for an increased vocabulary, while limited reading yields a smaller number of words learned.  Sometimes people find themselves in a cycle of only associating with a certain group of people.  The words of the group are the words of use while other words are actually eschewed.  This happens with religious groups who have a closed approach on group admittance.  Of course, educational level is one of the greatest indicators of restricted vocabulary.

Since vocabulary choices are a function of various factors, one might think it would be impossible to use it in detecting deception.  Quite the contrary.  Lies have to look like the truth.  Thus, it is easy to assume that the vocabulary choices would be the same as for words of truth.  But, a principle higher in the hierarchy of choosing words is the principle of looking smart.  The idea is that if one appears smart/intelligent, then the listener more easily will view it as the truth.  That has the affect of changing register from usual one used by the person.

One of the most common word changes involving register is the opinion many people have of using verbal extensions, what some call phrasal verbs.  Verbal extensions are the use of adverbs mainly to extend or slightly modify the meaning of the verb being used, for example hand out for deliver or give, or figure out for discover or calculate.  The word out is an extension to the verb hand and figure and extends or slightly modifies the meaning of hand and figure.  Many see the verbal extension construction as ordinary or less formal.  To sound smart, people will revert to one word synonyms.  Examples abound: return for come back, accept for buy into, leave for check out, produce for put out.  The list is long.

When a person uses fewer verbal extensions than his or her usual habit, the person views the topic or environment one in which he or she needs to appear smarter.  So, the person makes a register change.  That is precisely the place where prevarication appears.  So, one has to figure out if the person has true knowledge of the topic or a good comfort level in the environment.  If not, perhaps a little deception is occurring.