When the serotonin and dopamine systems are only utilized alongside the structures of the old brain, rewards tend to manifest as material status symbols or as a means of exerting control over things or groups of people. These rewards are either short-lived (e.g., a new car loses its novelty in three weeks) or come at the cost of suppressing or competing with others.
In contrast, when these systems are engaged in conjunction with the structures of the new brain—the social engagement system—the rewards are positive emotions such as gratitude, kindness, love, and humility. This also leads to an autonomic nervous system in homeostasis, resulting in a sustained state of contentment.