Reinforcement without awareness: II. Word class

In a previous study of reinforcement without awareness by Lieberman, Sunnuc ks, & Kirk (this issue), subjects were told that the experiment was on ESP; two words were presented on every trial, and their task was to choose the word the experimenter was thinking of. In fact, reinforcement was contingen t on the loudness of the subjects' voices when responding. They found stron ger evidence for reinforcement without awareness than in many previous stud ies, and they attributed their success in part to the reinforcement of a re sponse to which subjects were unlikely to attend. To explore this factor fu rther, we again used an ESP cover story but reinforced subjects for choosin g the word in each pair that contained a double letter. We found evidence o f reinforcement without awareness in three experiments and also identified two factors that influence these effects: Learning did not occur if subject s (a) were encouraged to test irrelevant hypotheses, or (b) sat in an uncom fortable chair. We speculate that learning without awareness may be more li kely when subjects are relaxed and that hypothesis testing and uncomfortabl e chairs impair such learning because they prevent relaxation.