These are the inherent inner opposites of the human psyche.
Every male has a femnine component to his psyche, and every Female has a masculine component to her psyche. This is often this is outwardly reflected as their "perfect other".
In many aspects this inner image of self, or the soul-image is often the middle layer of our self. This can be seen as either a personification of the ego, the Higher Self (or in some cases the Child Self). This Inner Self has many opposite traits that is possesed by the Waking Self (the self that is used to related to the outside world, and to deal with outside social stimuli).
If one can accept and intergrate this soul-image, one has a better chance at perhaps filling in certain personal deficiencies.
Often the soul-image is the comparing factor we use subconciously of the "type" of person we are most attracted to in general. This can cause issues as we begin to overlay what we /want/ to see in a person rather then what they really are in fact.
The original Latin is quite literally soul or mind; so for some of us anima is a term preferred over phenotype
, etc. to describe our Inner Self and what manner of being it reflects.