The self-portrait holds a special place in early 20th-century German and Austrian art. We get scant biographical details and virtually no analysis of why a painter might present himself as a lurid grotesque or in sober flecks of black, with an easel or without. As with most of what goes on in the looking glass, the exhibition depends on a certain amount of artifice and deception. Portraitists hope to burrow beneath the skin and into the subject’s inner life. Self-portraitists aspire — or pretend — to excavate their own psyches.