Differential effects of noise and incentives on learning. 
Three experiments are reported.  In the first, monetary incentives improved the learning of nonsense words in response to colours only when the test order was the same as presentation order.  In the second, incentives increased the recall of spatial location which served as an additional retrieval cue for nonsense words.  In the third, noise was used to manipulate arousal.  Noise during learning produced a significant decline in recall of locations for nonsense words.  The results suggest that incentives increase attentional capacity, while noise does not.  Previous results showing that noise increases the use of order cues are discussed and it is suggested that noise induces a type of learning which depends on order cues.  Existing hypotheses about the nature of this process are noted but it is argued that further work is needed to select between them.