In Death of a Salesman how does Arthur Miller use stage directions to further develop the interactions between his characters?
WILLY, with casual irritation: I said nothing happened. Didn't you hear me?
LINDA: Don't you feel well?
WILLY: I'm tired to the death. The flute has faded away. He sits on the bed beside her, a little numb. I couldn't make it. I just couldn't make it Linda.
LINDA, very carefully, delicately: Where were you all day? You look terrible.
WILLY: I got as far as a little above Yonkers. I stopped for a cup of coffee. Maybe it was the coffee.
WILLY, after a pause: I suddenly couldn't drive any more. The car kept going off onto the shoulder, y'know?
LINDA, helpfully: Oh. Maybe it was the steering wheel again. I don't think Angelo knows the Studebaker.
(Death of a Salesman, Act I)
If you take a look at each set of directions given in this segment, they are almost all adverbs or adverbial phrases. An adverb tells how something is done, it answers a question about the action at work. Thus, Miller takes out the room to question how to act - he gives it directly to the actors. Each direction therefore puts further meaning into the discussion taking place.
For example when Linda, very carefully, delicately asks "where were you all day? You look terrible," it demonstrates sincere concern. Without the stage direction an actor at first glance could think this specific line should be expressed with contempt or anger as if Linda's mad that he's been gone all this time.
Miller insinuates feeling and degree of tenderness by his stage directions. This assists the reader or actor with interpretation of the relationships characters encounter.
The stage directions given here clarify the relationship between Willy and Linda. We see that Linda is an anxious and loving wife even although Willy appears rather impatient and abrupt, when he answers her 'with casual irritation.' She is worried about him but inquires after his health 'carefully', as she doesn't want to annoy him. This suggests that Willy is rather of a volatile nature, and this is certainly borne out in the course of the play. As for Linda, she is always thinking of Willy and worrying about his state of mind, while doing everything she can think of to support him. This is emphasized with the adverb, 'helpfully'; she tries to shift responsibility for Willy's car trouble onto to the garage mechanic.
The stage directions here also give an insight into Willy's confused, wandering state of mind which becomes ever more obvious as the play progresses. 'The flute has faded away. He sits on the bed beside her, a little numb.' The flute, which Willy's dad used to play, functions as a symbol of Willy's nostalgia for the past, and its music haunts him. When his memories 'fade' and he has to pay attention to the present, he becomes lost, as underlined here with the reference to him being 'numb'. It also appears something of an effort to him to gather his thoughts, as seen when he replies 'after a pause'.
The stage directions also show Willy and Linda sitting together on the bed. This shows us that they really are a close and loving couple, although ultimately, and sadly, they are not really able to help one another. Linda's well-meaning efforts to support her husband do not prevent him from killing himself at the end of the play; and although grateful for Linda's love, Willy also feels he has failed her and that she can't really appreciate what he's going through. There is a certain gap in communication and understanding between them which is evident even in this short extract.