While Ian Stevenson focused on cases in Asia, Tucker has studied American children.
Tucker reports that in about 70% of the cases of children claiming to remember past lives the deceased died from an unnatural cause, suggesting that traumatic death may be linked to the hypothesized survival of personality. He further indicates that the time between death and apparent re-birth is, on average, 16 months, and that unusual birthmarks might match fatal wounds suffered by the deceased.
Tucker has developed the Strength Of Case Scale (SOCS), which evaluates what Tucker sees as four aspects of potential cases of reincarnation; "(1) whether it involves birthmarks/defects that correspond to the supposed previous life; (2) the strength of the statements about the previous life; (3) the relevant behaviours as they relate to the previous life; and (4) an evaluation of the possibility of a connection between the child reporting a previous life and the supposed previous life".
A mechanism for reincarnation
Although critics have argued there is no physical explanation for the survival of personality, Tucker suggests that quantum mechanics may offer a mechanism by which memories and emotions could carry over from one life to another. He argues that since the act of observation collapses wave equations, consciousness may not be merely a by-product of the physical brain but rather a separate entity in the universe that impinges on the physical. Tucker argues that viewing consciousness as a fundamental, non-physical, part of the universe makes it possible to conceive of it continuing to exist after the death of the physical brain. He provides the analogy of a television set and the television transmission; the television is required to decode the signal, but it does not create the signal. In a similar way the brain may be required for consciousness to express itself, but may not be the source of consciousness.
On the other hand Susan Huelga, a lecturer in quantum mechanics at the University Of Hertfordshire, notes that brain dynamics are highly complex, and she finds that there is no more evidence that quantum mechanics is relevant in this field than that it is relevant regarding whether or not God exists. Previous [[quantum mysticism|appeals to quantum mechanics]] as an explanation for New Age or paranormal beliefs have been criticized by physicists who are experts in quantum mechanics as being based on incorrect or [[pseudoscience|pseudoscientific]] [[interpretations of quantum mechanics|interpretations]].