In a time burbling with misused and perverted intelligence, Steve Martin is a welcome apostle of pure idiocy. Not the corroded comforts of neuroticism (Woody Allen), not the subversive logic of madness and bad taste (Mel Brooks), but blessed idiocy is Martin's thing, and in director Carl Reiner he's found the perfect collaborator in creative cretinism. Well, not perfect, because as talented as Reiner is, the Martin movies he's directed and cowritten ("The Jerk" and "Dead Men Don't Wear Plaid") are a bit scrappy; they don't have the total personality of the Allen and Brooks movies. Still, with Reiner, Martin has created an endearing hero of our time, the Jerk, an updated version of the classic Fool. And in "The Man With Two Brains" they have produced more laughs per quartz-vibration than in any of their previous works.
In these flicks Martin has become a kind of thinking man's Jerry Lewis. Where Lewis at his best raised regression to a creative principle, Martin converts expertise into the highest form of imbecility….
[Steve Martin] has the quality of true comic mania. He's not doing shtick, he's acting, with a furious and funny intensity. Like Harold Lloyd, he makes you laugh because he creates a loser who somehow wins. It's this punch-drunk oscillation between triumph and defeat that's funny….
Jack Kroll, "Idiot's Delight," in Newsweek, Vol. CI, No. 24, June 13, 1983, p. 78.