Walk-in is a concept originating with the Spiritualist faith and popularised by the related, but not identical New Age movements and beliefs.
True walk-ins are a rare but real medical phenomenon which should be catalogued by Oliver Sacks if it hasn't been. It begins when an individual (frequently, but not always, female) is badly injured, falls ill or is in some way incapacitated, or seems to "die" on the operating table during surgery. After resuscitation, the person behaves in a manner completely at odds with earlier, established behaviour patterns. She or he may speak in an unknown language and identify by a different name, and may be very frightened and confused, or supernally calm.
Almost invariably, they state that they either do not know where the original inhabitant of the body has got to, or that the original soul has left it and gone on to Heaven, leaving them in charge. The new individual may say he or she is an angel, an older, more experienced soul, or less often, a brand new one who's never incarnated before. While the New Age belief system about walk-ins claims that these transitions can't occur involuntarily and that no soul walks into another's body without reason, the behaviour of some new people indicate that it may not always be so.
In classical cases, the change is immediately apparent; however, in cases where the new soul has enough information to take up the old life seamlessly, it may take weeks or months before one notices that a transition has indeed occurred. Occasionally, the old self returns after a period of months or years, and either the new self moves out, or they co-exist and may try to integrate into a single being.
This kind of walk-in is very similar to old-time, pre-Sybil cases of multiple personalities such as Mary Reynolds. A period of unconsciousness is followed by the manifestation of a new self. William James studied Reynolds and Ansel Bourne, and thought of multiple personality as something natural but not yet understood, rather than a mental disease. Boris Sidis in his 1903 book Multiple Personalities recorded similar cases, involving both men and women.
In 1979, Spiritualist author Ruth Montgomery published Strangers Among Us, a collection of accounts of walk-ins. She included her own New Age theories and some improbable historical research naming some renowned figures such as Thomas Jefferson as walk-ins. This and her follow-up book Threshold to Tomorrow brought the concept of walk-ins to the general public. A belief system grew up around the walk-in experience, complete with all the usual New Age attributes like "ascending into higher frequencies of evolution", Earth Changes, and the concept that the new person may possess a variety of psi powers unknown to we ordinary human beings whose vibrational levels remain unraised.
In order to seem more accessible, the New Age walk-in belief system now includes a number of variant experiences such as channeling, telepathic contact with extraterrestrial intelligences, or soul merging (where the original self remains present and co-exists or integrates with the new one). Checklists to determine walk-in status include name changes, career changes, interest in the study of psychic phenomena, a feeling that one is not really from Earth, or a sudden desire to move to a new environment. These can all be attributed to simple life changes such as adolescence or middle age, so obviously it's difficult to determine if a true walk-in has occurred. The most logical method would seem to be determining if any specific event historically connected with walk-ins (anaesthesia for surgery is one of the most common) occurred around the time you first started feeling differently.
The belief system states that all souls come to earth in order to accomplish missions of cosmic significance, and that a walk-in is a highly evolved soul who's here to help raise the vibrational levels of humanity and doesn't want to bother with the tedious process of incarnating in the usual fashion.
Walk-ins, according to New Age teachers, are not perfect like Ascended Masters, but are invariably more spiritual, compassionate and sympathetic than the original person. This must be news to the husbands of women who abruptly discontinue marital relations on the grounds that they are not the person whose name appears on the wedding license or that carnal love is not for those of higher vibrational frequencies. Separation and divorce are very common to the New Age walk-in experience.
The "otherkin" community defines walk-in as a person who believes that they share their body with one or more different entities or souls.
In the otherkin community it is understood that sometimes these entities just "walk into" the body of their host, without the host needing to depart; this can happen right after birth, or later in the life of the person concerned. The origins of these souls vary - some are human or animal spirits, others are creatures usually considered mythological, or extraterrestrial intelligences. They share the body space and take turns using the body, usually with permission and awareness. Unlike the classic or Sybil-like description of multiple personality disorder, these groups of minds usually get on rather well and contribute energy and ideas to the host individual's life goals, as well as helping with activities of daily living. Most people who experience this type of walk-in seem to be less concerned with insubstantial claims about "raised vibrations" and are generally devoted to creative pursuits.
Another phenomenon often confused with the abovementioned and classical walk-in experience is hosting. A host is a person who voluntarily shares his or her body with various entities, usually since birth, while retaining his own consciousness and sense of self. A person sharing his body with otherkin walk-in spirits can said to be hosting; but not all hosted spirits are walk-ins.
Some Hosts claim that the souls residing in their body are soul-bonded relatives, friends or lovers from a past life, very similar to old-time Spiritualist mediums who would allow a departed loved one to take up residence in their body temporarily or permanently. Sharing space and body time with this other spirit, these mediums were the first to have the term "multiple personalities" applied to them.
This voluntary possession or sharing of the body by more than one spirit is well known in many indigenous cultures. One of the central practices of Vaudon is to allow gods and saints to take temporary possession of human bodies, to give advice and help to all the people. Folk healing on the island of Bali can involve ceremonies in which departed ancestors take over a living body for the same purposes. For the ceremony called Sanghyang Dedari, two little girls are specially trained to become temporary vessels for a pair of angels, Tunjung Biru and Dewi Supraba, who come to remove bad luck and sickness from the village at the end of the monsoons. And in some Gulf Coast Indian tribes, leaders and healers are chosen from those who have the most spirits living inside them.
Generally, Walk-ins and Hosts say they are able to change between the persons residing in their bodies at will; in such situations, the main or host self (in most cases, this is the soul of the original inhabitant) simply "takes a step back" and lets another entity "come forward" to control the body.
People who find themselves in a hosting or walk-in situation are also in a larger category, generally referred to as Multiples by the otherkin community.
Those people usually stress that it is important to make a distinction between people who suffer MPD (Multiple Personality Disorder) and themselves. Again, unlike classical, Sybil-like blackout MPD, the host person is conscious of and able to communicate and cooperate with the others. They often prefer terms such as people or selves to "personality", which they consider misleading since it implies that each is not a separate being.
