Affect, according to Wundt, is a feeling state that is a fundamental ingredient of the human mind. The foundation of affective experience is the basic pleasure/unpleasure series of conscious states that mediate homeostasis—by telling us how well we are doing in terms of our fundamental biological task of getting our needs met for survival and reproduction. These elemental affects are closely linked with the operation of the seeking system, which correlates closely with Freud's idea of a multi-purpose ‘libidinal’ drive. In addition, we have evolutionarily conserved brain systems which subserve distinct instinctual emotions. These systems release specific behaviors, thoughts and feelings in response to appropriate stimuli.