In a changing world like the one we and many other organisms live in, forgetting some memories would be beneficial, they reasoned, as this can lead to more flexible behavior and better decision-making. If memories were gained in circumstances that are not wholly relevant to the current environment, forgetting them could be a positive change that improves our well-being.
"Kinship mind is a way of improving and preserving memory in relationships with others. If you learn something with or from another person, this knowledge now sits in the relationship between you." - Tyson Yunkaporta, Sand Talk