We always pursue simplification, which is positive in itself, in general, except when this will clash against phenomena that are intrinsically complex, not completely codifiable and dependent on the context in which they occur.
Simplification is a good thing, when this is possible, if only because it responds to a principle of economics, and reducing efforts, in a general sense, is more or less always a sustainable and desirable goal.
Simplifying when one should not - or could not - is however very dangerous: it is the road to the approximation and partial understanding, if not entirely incorrect, of a phenomenon; it is the way to easily draw wrong conclusions; it is the confirmation of what the popular wisdom tells us with "haste makes waste".
Very often, this extreme will of simplification passes through the enunciation of rules and/or causal links, which do nothing but give us the illusion that "if A then B", always and in any case, neglecting those infinite variations that, especially when the rules are directed towards us and towards our emotional states, are an essential element for a correct interpretation attempt.
In the case of non-verbal communication and its interpretation, this desire for simplification is rather manifested and realized in many "manual" (I’m not using deliberately the term "book" and I say "many" and not "all" since, fortunately, there are also exceptions) that pretend to codify the reading of the body with algorithmic rules, forgetting that one of the axioms of this discipline is precisely the fact of not being science and, therefore, hardly subject to a scientific approach, that be codifiable and repeatable.
How many times do we read - or others tell us - that "if our interlocutor crosses his arms, then he or she is closing, he does not agree, he is not willing to listen", or that "if someone says something and touches his lips, then he or she is lying". If everything were so simple, mechanical, each of us would be, if he were also a good observer, an excellence in the interpretation of body language. Obviously, this is not the case and the rules are just a starting point as signal receptors, which then must be analyzed, deepen and, only at the last, interpreted.
Every gesture, every movement of the body, is always "here and now" and it is affected by the experience of the issuing subject, of its emotional state, of its gestural habits and of the context in which communication is taking place. In other words, there are so many variables that the impossibility of an algorithmic application of the rules should be crystal clear but, even if the rule of the "3 C" and the basal behavior (1) should be the mantra of the interpreter, it's often not like that: we know we should take it into account, but we often tend not to do it, assigning a certainty to a feeling, a hypothesis, preferring a conclusion like "crossed arms, then closed" to a starting point for analysis, as, for example, "his crossing his arms does not seem in line with what he is saying and with the immediately preceding gestures" .
Seeing it in other terms , this tendency to mechanization of interpretation is nothing but a sort of prejudice about the effectiveness of the rules, a prejudice on the trust that can be placed in them, which often comes from forgetting that - and here I hope all agree - the interpretation of body language is not an exact science (what is closest to it is the studies and results achieved by Paul Ekman on facial expressions of so-called universal emotions (2) (3), but these, too, as the author points out, are always influenced by external and contingent elements from which we cannot ignore).
But we must not be pessimistic and the caution just discussed must be seen as an incitement to reflection, to the careful analysis of what the body communicates, to never forget the past of the interlocutor and the present in which communication takes place, to always keep in mind the mimic and gestural habits of those in front of us and, finally, and with the utmost attention, what we communicate with the unsaid and the influence that this has on those facing us. Andrea Zinno - De Corporis Voce