Scientific Understanding of Consciousness
Retrieval of Knowledge Enhances Learning
Science 11 February 2011: Vol. 331 no. 6018 pp. 772-775
Jeffrey D. Karpicke and Janell R. Blunt
Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
Educators rely heavily on learning activities that encourage elaborative studying, whereas activities that require students to practice retrieving and reconstructing knowledge are used less frequently. Here, we show that practicing retrieval produces greater gains in meaningful learning than elaborative studying with concept mapping. The advantage of retrieval practice generalized across texts identical to those commonly found in science education. The advantage of retrieval practice was observed with test questions that assessed comprehension and required students to make inferences. The advantage of retrieval practice occurred even when the criterial test involved creating concept maps. Our findings support the theory that retrieval practice enhances learning by retrieval-specific mechanisms rather than by elaborative study processes. Retrieval practice is an effective tool to promote conceptual learning about science.
It is beyond question that activities that promote effective encoding, known as elaborative study tasks, are important for learning. However, research in cognitive science has challenged the assumption that retrieval is neutral and uninfluential in the learning process. Not only does retrieval produce learning, but a retrieval event may actually represent a more powerful learning activity than an encoding event. This research suggests a conceptualization of mind and learning that is different from one in which encoding places knowledge in memory and retrieval simply accesses that stored knowledge. Because each act of retrieval changes memory, the act of reconstructing knowledge must be considered essential to the process of learning.
Elaborative learning activities hold a central place in contemporary education. We examined the effectiveness of retrieval practice relative to elaborative studying with concept mapping. In concept mapping, students construct a diagram in which nodes are used to represent concepts, and links connecting the nodes represent relations among the concepts. Concept mapping is considered an active learning task, and it serves as an elaborative study activity when students construct concept maps in the presence of the materials they are learning. Under these conditions, concept mapping bears the defining characteristics of an elaborative study method: It requires students to enrich the material they are studying and encode meaningful relationships among concepts within an organized knowledge structure.
Retrieval practice is a powerful way to promote meaningful learning of complex concepts commonly found in science education. Here, we have shown that retrieval practice produces more learning than elaborative studying, and we used concept mapping as a means of inducing elaboration while students studied. We hasten to add that concept mapping itself is not inherently just an elaborative study task. When students create concept maps in the presence of materials they are learning, the activity involves elaborative studying. Students could also create concept maps in the absence of materials they are learning, and then the activity would involve practicing retrieval of knowledge. Nevertheless, both elaborative concept mapping and retrieval practice are active learning tasks, and our results make it clear that whether a task is considered “active” is not diagnostic of how much learning the task will produce. The specific nature of the activity determines the degree and quality of learning, so understanding the nature of encoding and retrieval processes is crucial for designing educational activities.
There are several theoretical reasons to expect that the processes involved in retrieving knowledge differ fundamentally from the processes involved in elaborative studying. During elaboration, subjects attain detailed representations of encoded knowledge by enriching or increasing the number of encoded features, but during retrieval, subjects use retrieval cues to reconstruct what happened in a particular place at a particular time. In free recall, subjects must establish an organizational retrieval structure and then discriminate and recover individual concepts within that structure. Retrieval practice likely enhances the diagnostic value of retrieval cues, which refers to how well a cue specifies a particular piece of knowledge to the exclusion of other potential candidates. Rather than multiplying or increasing the number of encoded features, which occurs during elaboration, retrieval practice may improve cue diagnosticity by restricting the set of candidates specified by a cue to be included in the search set. Thus, mechanisms involved in retrieving knowledge play a role in producing learning.
Research on retrieval practice suggests a view of how the human mind works that differs from everyday intuition. Retrieval is not merely a read-out of the knowledge stored in one’s mind; the act of reconstructing knowledge itself enhances learning. This dynamic perspective on the human mind can pave the way for the design of new educational activities based on consideration of retrieval processes.
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Return to — Learning
Return to — Memory Consolidation
Return to — Associative nature of Memory
Return to — Declarative Memory as Reconstruction