What makes a witness trustworthy? Why are some witnesses believed and others not? Standard responses would be: “Someone who has the ability to perceive events accurately.” “Someone who is unbiased.” “Someone who is an authority in their field.” “Someone whose facts and opinions are corroborated by other evidence.” Etc. These are commonly asserted, but there are other aspects as well to trustworthiness.
Conformity. A believable witness conforms to normative, socially accepted conventions and expectations. This probably plays a larger role than expected. The peculiar, the idiosyncratic, the irregular––trustworthiness falters if the witness holds to a view no one else shares. We subconsciously reward conformity since it takes extra mental effort to process, and accept, nonconformity.
Verifiability. Can the statements of the witness be verified by other means? If the witness is the only one who can substantiate what’s being said, this leaves a gap––others are left with no basis to confirm or refute. When no commonsense method exists to verify, it’s too easy for others to conclude the statements made are baseless. This too probably plays a larger role than expected. Ideally, what’s being said should be capable of being proven in any number of ways.
Obviousness. A believable witness is clothed in the garb of obvious truth. Stark reality awaits; daylight shines its light. We do not believe what we cannot understand. Trustworthy statements should seem obvious, resistant to contradiction, so that any challenge would appear to fly in the face of our most basic understanding, our common sense.
These, however, are not enough. There’s an indefinable aspect as well. Call it “durable authenticity”––a genuineness of thinking, reasoning, and perception that cannot be feigned or imitated, eroded or undermined. But even trustworthy witnesses are sometimes not believed. From this week’s Economist: “But as Mr. Frimer’s experiment suggests, psychological explanations also suggest that people are willing to dismiss or deny facts and opinions that run counter to their beliefs. Such behavior might seem short-sighted and self-defeating. But in a book of 2017, “The Enigma of Reason,” two cognitive scientists, Hugo Mercier and Dan Sperber, argue that reasoning did not evolve “to help individuals achieve greater knowledge and make better decisions”. Rather, they say, it evolved to improve the ability of ancestral hunter-gatherers to co-operate in small groups. As they put it: “What reason does…is help us justify our beliefs and actions to others…and evaluate the justifications and arguments that others address to us.” In other words, a lot of reasoning is devoted to affirming your group’s identity and your position within it.”
Not some top-lofty mental capacity––reasoning perceived as but a method of affirming group identity and position. This harks back to the idea of conformity. Your witnesses, and their facts and opinions, should, at least to some extent, fall within reasonable norms. This explains why some opinions are not accepted––they do not support, or fit within, the thinking of the group.
Even a person’s facial features can influence the perception of their trustworthiness:
“There is good agreement among observers that some people’s faces look more trustworthy than others (e.g. Winston et al. 2002; Todorov et al. 2008), although there is no evidence that these judgements have any validity. Todorov et al. have identified four facial features that drive the perception of trustworthiness. One of these is the height of the inner eyebrow. Faces with high inner eyebrows look trustworthy. Those with low inner eyebrows look untrustworthy. These differences can be interpreted on the basis of the results of Watt et al. Trustworthy people have raised eyebrows so that observers can see where they are looking. Untrustworthy people have lowered eyebrows so that observers have more difficulty in seeing where they are looking. Given these observations, we can interpret the eyebrow flash as a signal that the sender is to be trusted. Raised eyebrows enable eye gaze direction to be seen more easily, thereby helping to reveal the intentions of the sender. As an ostensive gesture, the eyebrow signals that the message which follows will be relevant and true.”
Something as simple as enabling others to track “eye gaze direction” can be linked as well to the notion of group identity and position––you’re making clear your intentions and demonstrating to others your motive and purpose. What this implies is that the “eye gaze direction” of your words and statements should be trackable––they should be capable of revealing to the group both your meaning and purpose. Witness preparation should include some sensitivity to this area. Thus, the time-honored advice that your witnesses should “look at the jury” when they’re about to reveal their most important points. You probably should create a checklist of physical movements and gestures you and your witnesses should be aware of, both positive and negative, before speaking to others. And then to ask: how trustworthy will be this witness? It’s all in the gaze.
 The Economist Pg. 33, The Partisan Brain, (December 8th– 14th, 2018)(Volume 429/Number 9121)
 Chris Frith, Role of Facial Expressions in Social Interactions, Phil. Trans. R. Soc. B (2009) 364, 3453–3458 doi:10.1098/rstb.2009.0142 /