Lamar has just gotten a new job and is attending a company party where he will meet his colleagues for the first time. His boss escorts him around to small groups to introduce him. At the first group, Lamar meets four people and is told only their first names. The same thing happens with a second group and a third group. At the fourth group, Lamar is told their names and that one of the women in the group is the company accountant. A little while later, Lamar realizes that he only remembers the names of the people in the first group, though he also remembers the profession of the last woman he met (the accountant). Lamar's experience demonstrates

When a person tries to recall some information that are older in nature and comes to know about some recent information it refers to Retroactive interference. For instance you may call the name of your grandmother with the name of your mom. There will be a retroactive interference with the two names.

This happens when you forget some tasks that are learnt in past because of the learning of new tasks. In the given example, Lamar only rememnbers the names of the people in the first group and remebers the profession of the last women met by him. His experience demonstrates retroactive interference.