Living things often become less responsive to a repeated stimulus over time, a process called habituation. To regain sensitivity, the stimulus must either be stopped for a while or gradually made stronger. This biological process helps us adjust to both good and bad stimuli. For example, when entering a very smelly place, the strong odor is initially unpleasant. However, within minutes, we notice the smell less because our sense of smell adapts. From an evolutionary view, this desensitization to repeated stimuli within the central nervous system (CNS) helps filter out constant, unimportant signals. This allows the brain to focus on newer or more critical information. For instance, in a noisy crowd, the brain ignores ongoing background sounds to pay attention to sudden or relevant noises.

At the social level, things we enjoy often become less exciting after we experience them repeatedly. Even the best entertainment, places, restaurants, or hotels can start to feel ordinary after several visits. To feel the same level of pleasure again, we often need to try something new. However, this process may also be a hidden reason for problems in our social relationships with others, such as an intimate friend or a colleague.1

Dopamine is a neurotransmitter that primarily functions within the brain's reward system, which consists mainly of the ventral tegmental area (VTA) in the brainstem and the nucleus accumbens. These two components also closely interact with the limbic system, which is a collection of brain structures that play an essential role in regulating emotions, memory, motivation, and instinctive behaviors.

In his book, The Molecule of More, Daniel Lieberman argues that dopamine is the main neurotransmitter in the reward system, driving desire, motivation,........

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