The Influence of Childhood Rearing on the Separation and Individuation Process of Twins

Research has evolved to show that the psychological development of twins is different than non-twins and that they must undergo a secondary separation. Whether this additional separation puts twins at greater risk for developmental difficulties remains unresolved and confounded based on the current twin literature. This study sought to clarify these inconsistencies by examining the relationship between being reared the same in childhood (CRHQ) and difficulties with separation and individuation in adulthood (PDI Scales I-VI) for twins (experimental group) and non-twins with a sibling born within three years of their birth (control group). Participants were recruited using MTurk and included 106 adults within the US between the ages of 20-40 years old. Initial analyses included independent samples t-tests to determine differences between twins and non-twins on the CRHQ and PDI, and primary analyses involved ANCOVAs to examine differences in the relationship between CRHQ and PDI scales across groups. Results revealed that CRHQ predicted four PDI scales for twins and non-twins, although twins had greater scores on the CRHQ and PDI scales. The study concluded that while twins are not exclusively vulnerable to the negative consequences in ego development of being reared the same as a sibling, they are more at risk. Clinical applications, limitations, and future directions are discussed. Keywords: twins, separation and individuation, identity developmen