Final answer:
Liz and Joel's relationship satisfaction will likely deepen as they spend more time together, especially if their relationship exceeds their respective comparison levels of intimacy and commitment, reflecting a balance of benefits over costs according to social exchange theory.
Step-by-step explanation:
As Liz and Joel start spending an increasing amount of time together engaging in activities such as playing pool, taking dance lessons, and surfing, and as they are also sharing an increasing number of their personal thoughts and feelings with each other, their satisfaction for their relationship will continue to deepen if the relationship exceeds their respective comparison levels. This is supported by social exchange theory, which suggests that individuals are looking for relationships that offer greater benefits than costs compared to their expectations or 'comparison levels'. It is through the mechanism of self-disclosure, where individuals share personal information, that intimacy is built, and when the intimacy in a relationship meets or exceeds their comparison levels, satisfaction often deepens. Additionally, Sternberg’s theory of love indicates that a consummate love, which involves intimacy, passion, and commitment, leads to a healthy and satisfying relationship.