While spotting a liar,is it paying attention to verbal cues such as pauses in speech and speech disturbances, including "ahs," stutters, and incomplete sentences that weighs more or is it paying attention to non-verbal cues such as inconsistent eye contact, increased degree of eye contact, blink frequency, chin movement that weighs more
It is not entirely clear whether you are asking how much weight should we place on different cues (if we want to spot liars) or how much people actually do use these cues. There is a big literature on lie detection though. Here is a recent paper that discusses some of this work and will give you a start.
Some of the salient points are:
- People are actually pretty bad at guessing truths and lies, though it is hard to do experiments on.
- Although there are some cues that give people away, these are faint and unreliable. The most reliable ones are actually just the things that they say (the facts).
- Non-verbal cues and speech disturbances are actually pretty poor cues even though people think they are good ones. They are also pretty easy to fake.