Steve regularly surprises his wife, Marla, with flowers and gifts and always tries to make her feel special by taking her out to fancy restaurants and on holidays. However, he feels that his wife takes him for granted and does not truly appreciate what he does for her. According to the social exchange theory, .

Steve's costs are greater than his rewards.

Explanation:

The Social Exchange Theory, as it's name suggests, uses a cost-benefit analysis, which determines outcomes and relationships measured in costs, benefits and rewards from any type of interaction between two parties. This theory is used by both sociologists and psychologists to study the behavior of the two selected parties, groups or individuals.  Now, in this case, Steve's costs are greater than his rewards given that he makes the effort to surpise Marla, going out of his way to try and make her happy. But, given that he feels that he is taken for granted, one could argue that, effectively, his costs are greater than his rewards.

the declaration states, “we hold these truths to be self-evident, that all men are created equal, that they are endowed by their creator with certain unalienable rights, that among these are life, liberty, and the pursuit of happiness….”