Learning by exploration and affordance bugs

Modem highly visual interfaces can often be learned largely by exploration, without human or textual instruction. We should take this seriously as a major design @ because of its advantages when successful, and because it largely succeeds in many cases. For instance, computer naive subjects and have them discover and use many of the features of MacPaint within the ftrst half hour of use, without any instruction. However observation reveals many remaining imperfections — bugs relative to the aim of supporting learning by exploration (LBE). Thus an aim of evaluation and debugging of such designs is to address those usalility problems impeding LBE.