An article11 that analyzed the effects of the levels of the participant’s generosity and of the spouse’s generosity on a measure of marital quality reported that low levels of both were associated with low marital quality and high levels of both were associated with high marital quality. However, when the participant reported low levels of generosity toward the spouse, but the spouse reported high levels of generosity toward the participant, marital quality also tended to be low. For a regression model predicting marital quality, do you think it is adequate to use main effects alone, or do you probably also need an interaction term? Explain.