Considerable chatter regarding physical tells exists and is neatly summarized in the Mike Caro classic.
However, there is a real problem within the lack of reliability in physical tells.
Good players can utilize reverse tells and bad players tend to be inconsistent.
… we all know how expensive a misread can be ...
Better players need to look a little deeper into their opponents actions.
It is funny how little play the topic of synchrony gets in the “tells” literature.
Synchrony refers to either occurrence at the same time or movement at the same rate. Synchronous actions are innate and very difficult to fake. Where it equates to bluffing/deception relates to the congruency of a player’s actions/words. Bluffing is likely occurring when synchrony does not occur between what is being said and the events at the time.
Things to look for:
1) Does my opponents head movement match their answer to a yes-or-no question?
2) Is there a noticeable delay in answering yes-or-no questions?
If the answer to the first question is no or to the second question is yes, then you have likely observed non-synchronous behavior and have more often than not sniffed out a bluff.