“Effie Perine sat up straight and said, ‘Sam, if that girl’s in trouble and you let her down, or take advantage of it to bleed her, I’ll never forgive you, never have any respect for you, as long as I live.’ Spade smiled unnaturally.  Then he frowned.  The frown was unnatural.”(42)

Spade’s reaction to Effie’s statement is very revealing of the way he uses facial expressions as instruments to mask his true intentions in social situations and to manipulate others through their subconscious reactions.  His unnatural smile at the mention of bleeding O’Shaughnessy is meant to invoke a feeling of sincerity and honesty while covering his actual intention, to acquire as much money as possible from this case.  He does something similar when he first meets O’Shaughnessy for the first time.  As she speaks, he is supposedly “integrating smiles and nods”(7) in order to give her a sense of “assurance.”  In both instances, Spade is using fake smiles to convey a sense of honesty.  Spade hides his intentions through his facial expressions, such as when he is speaking to O’shaughnessy in her apartment.  When it says that “the upper part of his face frowned.  The lower part smiled,”(33) Spade is trying to hide his feelings from O’shaughnessy because he doesn’t want her to know how he feels about her or the case.  His creation of such an unreadable facial expression is a clear indicator of his unwillingness to reveal even the smallest iota of his inner workings; he does not want to express a positive or negative emotion that would give his thoughts away, thus his fusion of both a “frown” and a “smile.”  Spade’s smile is a finely crafted instrument that allows him to mask his true emotions, allows him to invoke false feelings of confidence in others, and allows him to hide his intentions from anyone who would stand in his way.  Spade is an accomplished detective and he uses all tools at his disposal, including ones that allow him to both gather information from others and keep others from gaining information about him.