I have always been intrigued by the stories that I hear from twins about being competitive. Many twins appreciate sharing in the successes of their sibling. Many twin athletes who compete in the same sport, for example, say that they would rather see one of them win than both lose. The motivating companionship of the experience makes the competition invigorating and exciting rather than mean-spirited and malicious.
Twins who play competitive sports have a healthy outlet for competitive feelings. In contrast, other twin pairs suffer tremendous emotional turmoil in response to competitive circumstances. Their internalized, unarticulated reactions build up over time. Younger twins often express their hostile feelings through physical and verbal assaults on one another. As they get older, these feelings may be expressed by one twin wanting to shun the other under the guise of searching for separateness. The most pernicious outcomes of twin competition seem to develop between twins who are excessively interdependent and have joined forces as a formidable unit to survive cruel peer relationships and unsupportive home environments.
Cases of anorexia nervosa in identical twin girls illustrate the extremes to which this unhealthy and unwanted enmeshment can lead. Until each twin can comfortably talk about her authentic feelings, internalized competitiveness gets played out physically in a dangerous battle of starvation. One twin may be jealous that her sister can withstand hunger and deprivation longer than she can. Ironically, the twin who first eats again feels like the loser. For healthy change to occur, the twins must develop an understanding of their dynamics as well as recognize that their connection needs to be redefined and respected.