These words refer to effort or understanding that is not searching or profound or that does not go deep. Superficial and shallow may both literally indicate a lack of depth: superficial wounds; shallow water . In this context, superficial suggests a cursory or hasty approach, an undue interest in trivialities, or a personality that by choice is not genuine or sincere: a superficial glance at the newspaper; a superficial life of self-indulgence, giving him a polite but superficial welcome. By contrast, shallow applies not to a refusal to go into something deeply, but an inability to feel, sympathize or understand: youngsters who rush into marriage with only the shallowest notions of what love and responsibility entail; a shallow indifference to the sufferings of others; a shallow anthropocentric view of the universe. Shallow might seem the more condemnatory of the two words, except that superficial , in suggesting that a better or more painstaking effort is possible, would seem to indicate less forgivable failings: a superficial approach to the problem that was the result of a lazy rather than a shallow mind.

Obvious and flat more often refer to the poor results that are to be expected from superficial efforts or shallow approaches. Obvious , of course, is very general, with a wide range of uses. In this context, it may be pertinent to an effort that attempts to go beyond the superficial but fails: an obvious treatment of problems better dealt with by other scientists: an obvious , if not silly, plot that vitiates the playwright’s ability to create genuine conflicts. In this context, flat suggests an obvious result without any sign of ability or desire to accomplish more: the novel’s flat , one-dimensional characters. It can suggest also something that has lost any value it once had: a story which was widely admired in the 1890s but seems flat to us today. As can be seen, both these words are often used to criticize works of art, particularly of a narrative sort, with obvious applying to action or plot, flat to the creation of character: The author’s superficial approach, his obvious story line, and his flat characters all betray evidence of a shallow mind.