If one has recently attended several parties, one may have a hard time remembering the details of the events that occurred at any one particular party. that person's difficulty demonstrates that a(n) memory can be by exposure to similar information.

Episodic; weakened                                                                    

Explanation:

Episodic memory: In psychology, the term episodic memory is part long-term memory, and is described as the memory of an autobiographical event, for example, places, associated emotions, time, etc that can be conjured or stated explicitly.

In other words, the episodic memory is the collection of an individual's past personal experience that happens during a specific place and time.

According to the information processing model, the episodic memory of a person gets hindered when two or more related events occur simultaneously.

In the question above, a person's difficulty demonstrates that episodic memory can be weakened through the exposure to similar information.

the answer to your question is,

old stone age.

-mabel < 3