When katie was making a cake using a new recipe, she mistakenly used some of the ingredients from an old recipe she had used often, best illustrating interference. when laurel got a new combination lock, she forgot the combination for her old lock, best illustrating interference.

proactive; retroactive

Explanation:

Proactive interference: The term proactive interference refers to the process when an individual's old memories hinder him or her from retaining new memories.

Retroactive interference: The term retroactive interference refers to the process when an individual's new memories hinder him or her from retaining old memories. In other words, the new memories of a person disrupts the old memories.

In the question above, Katie is experiencing proactive interference, whereas Laurel is experiencing retroactive interference.