To some extent, yes. Psychologists have tested this in various ways, including asking people to spend time learning pairs of words, and then asking them to deliberately forget some of them. Future memory for the deliberately forgotten words tends to be poorer. More recently, researchers have extended this concept to show that people can unlearn behavioural habits acquired in the lab (such as particular finger movements paired with specific words), and they’ve found that after a period of deliberately not thinking about a particular autobiographical episode from their lives, people show a loss of memory details for that episode.