In an experiment, Jay and Alissa are injected with the same concentration of a harmless drug. The purpose of the drug is to create arousal in the subjects who are injected. After a while, the arousal manifests as anger in Jay and as happiness in Alissa. Jay felt angry that he was injected with an unknown substance, but Alissa was happy to be a part of the experiment. These experimental findings can be explained by the _________.