TIL a peer-reviewed psychology study found that identical twins (on average) ranked their co-twin above their romantic partner in their attachment hierarchy, while fraternal twins ranked the two about equally, and non-twin siblings ranked their romantic partner first.

TIL a peer-reviewed psychology study found that identical twins (on average) ranked their co-twin above their romantic partner in their attachment hierarchy, while fraternal twins ranked the two about equally, and non-twin siblings ranked their romantic partner first.