Induction effect describes the result of introducing particular mental states or moods in individuals. Induce means to bring something about or be the cause of a result by generating something.
For example, some researchers are interested in how mood influences memory. For their study they want to see how much recall individuals in a bad mood have versus how much recall those in a good mood have. Before the recall test the researchers give the two groups passages intended to induce a negative mood in one group and a positive mood in another. The induction effect would be the resulting moods that were elicited by the passages the researchers gave the participants.