Final answer:
Derek's difficulty in recalling his new password owing to remembering the old password is an instance of proactive interference, which is when old information prevents the recall of new information.
Step-by-step explanation:
Derek's email log-in experience, where he remembers his old password instead of the new one he created, is an example of proactive interference. This type of interference involves situations where old information hinders the recall of newly learned information. Proactive interference is a common phenomenon, often experienced when a change like a new phone number, address, or even a new year causes us to refer back to the old, familiar information instead of the new. In the case of passwords, this is a reflection of procedural memory, a type of long-term memory involved with the performance of different actions and skills. It encapsulates the habits and routines that have been established over a long period of time.