Retrieval interference is a phenomenon that suggests some memories can disrupt the recall of new or old memories. There are two types of retrieval interference: proactive and retroactive. Proactive interference occurs when information learned earlier disrupts the later learning of information. Older memories are more firmly encoded in long-term memory due to the individual having more rehearsal time. That makes those memories easier to recall than more recent memories. Research shows that one way to lessen proactive interference is to rehearse new information through recitation.
On the other hand, retroactive interference happens when information learned later interferes with information that was learned earlier. Sleep is a factor that helps avoid retroactive interference, resulting in better recall because nothing is disrupting the memory. Retroactive interference has been shown to interrupt learning. In a study, participants learned a set of German-Japanese word pairs and then a different set as an interference task. Regardless of the time between the learning and interference tasks, the interference task reduced learning by up to 20%, showing that the set learned later interfered with the memory of the German-Japanese word pairs learned earlier.
In an example of retroactive interference, the experimental group, who learned about mountains after a list of rivers, performed less well on recall tests. The later-learned list of mountains confused their recall of the earlier-learned list of rivers, unlike the control group, which experienced no interference from an unrelated task. In proactive interference, the experimental group experienced the effects of proactive interference because the earlier-learned list of rivers disrupted their memory of the later-learned list of mountains. Their recall performance on the mountain list was lower than that of the control group.
As a competitive dancer, I continuously learn new choreography and dance moves on a daily basis. I have about 10 routines a season that I have to memorize, which tends to get difficult as I learn more choreography. At the start of the dance season, I quickly picked up new combinations without interference from other routines because I had a break during summer and did not learn anything dance-related. However, as the season continues and I learn more routines, I notice instances where I unintentionally do dance moves from routines learned months earlier. This became specifically noticeable when, for example, an arm movement called a windmill, learned in October for a Halloween dance, found its way into a routine learned in December. The step was the same in both dances, but the arms were different. However, I could never remember the arms in the later-learned step because the arms from the step we learned in October interfered with it. Understanding the phenomenon of proactive interference helped me realize that the earlier-learned arm movement was interfering with my recall of the later-learned movement.
Sources:
https://www.simplypsychology.org/proactive-and-retroactive-interference.html
https://study.com/academy/lesson/proactive-interference-definition-examples-quiz.html
https://www.thoughtco.com/proactive-and-retroactive-interference-definition-and-examples-4797969
