Several modifications of the Asch experiment in which the S judges the length of lines in the company of a group of "stooges" who carry out the experimenter's instructions are described. These include a face-to-face situation, an anonymous situation, and a group situation, with self-commitment, public commitment and Magic Pad commitment variations. The results indicate that, even when normative social influence in the direction of an incorrect judgment is largely removed (as in the anonymous situation), more errors are made by Ss in experimental groups than by Ss making their judgments when alone. (PsycINFO Database Record (c) 2006 APA, all rights reserved)