-The model is based on relationships from individualist cultures, where ending the relationships is a voluntary choice, and separation is easily obtainable and doesn't carry stigma. this may not be the case in collectivist cultures, where relationships are sometimes arranged by wider family members, and characterised by greater family involvement. This makes the relationship difficult to end, meaning the break-up process will not follow the phases proposed by Duck. As a result, Duck's model is culturally biased as it assumes that break-up process is universal, which is not the case.