Proactive interference can be described as a situation whereby past memories make it difficult for an individual to retain new memories. It occurs when a material or an item learnt in the past causes an interference effect such that newer materials or items are difficult to acquire or retrieve.
On the other hand, retroactive interference occurs when a more recent information makes it difficult for an individual to recall or remember older information. This implies that new memories are preventing a person from retaining older or more previous information.
From the question therefore, when you enter an old password to retrieve your email, rather than entering your new password, you are demonstrating proactive interference. On the other hand, not being able to recall your old phone number is an example of retroactive interference.
Interference theory separates memories in chronological order, based on when they were acquired, to understand how people have difficulty remembering certain information.
Proactive interference occurs when you are trying to remember something that you have memorized relatively recently and a past and separate memory gets in the way.
Retroactive interference occurs when you are trying to remember something you have memorized in the past and something similar that you have learned since that time hinders your ability to correctly associate what matters.
