Traditionally, the concept of personhood entailed the soul , a metaphysical concept referring to a non-corporeal or extra-corporeal dimension of human being which is absent in other creatures. Today, the concepts of subjectivity and intersubjectivity , personhood , mind , and self have come to encompass a number of aspects of human being previously considered the domain of the "soul".   Thus, while the historical question has been: when does the soul enter the body , in modern terms, the question could be put instead: at what point does the developing individual develop personhood or selfhood. 
The survey’s margin of error is the largest 95% confidence interval for any estimated proportion based on the total sample – the one around 50%. For example, the margin of error for the entire sample is ± percentage points. This means that in 95 out of every 100 samples drawn using the same methodology, estimated proportions based on the entire sample will be no more than percentage points away from their true values in the population. Sampling errors and statistical tests of significance used in this report take into account the effect of weighting. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.