Their libidinal hyperactivity accords with [Herbert] Marcuse's belief in the liberatory power of eros. Sigmund Freud argued that grief is a process of libidinal reinvestment. Kernberg defines normal narcissism as the libidinal investment of the self. Self-constancy is an important step in childhood cognitive and libidinal development. Good, pleasurable interactions with others consolidate, over time, into a pleasure-seeking (libidinal) drive. The child's good and bad affects become consolidated and shaped into libidinal and aggressive drives. Commentators have compared "Libidinal Economy" to Deleuze and Guattari's "Anti-Oedipus".