Research dating back a century has shown that retrieval contributes to learning, but the past decade has seen a renewed, intense focus on exploring the benefits of retrieval for learning:
This recent research has established that repeated retrieval enhances learning with a wide range of materials, in a variety of settings and contexts, and with learners ranging from preschool ages into later adulthood (Balota, Duchek, Sergent-Marshall & Roediger, 2006; Fritz, Morris, Nolan & Singleton, 2007).
A word-learning experiment illustrates some key points about retrieval-based learning. In the experiment (Karpicke & Bauernschmidt, 2011), students learned a list of foreign language words (e.g., Swahili vocabulary words like “mashua — boat”) across cycles of study and recall trials. In study trials, the students saw a vocabulary word and its translation on the computer screen, and in recall trials, they saw a vocabulary word and had to recall and type its translation. The students studied a list of vocabulary words, then attempted to retrieve the whole list, studied it again, retrieved it again, and so on across alternating study and retrieval practice blocks.
There were several different conditions in the experiment. In one condition, students simply studied the words once, without trying to recall them at all. In a second condition, students continued studying and recalling the words until they had recalled all of them once. After a word was successfully retrieved once, it was “dropped” from further practice — the students did not see it again in the learning session.
Other conditions in the experiment examined the effects of repeated retrieval practice. Once a word was recalled, the computer program required the students to practice retrieving the items three more times. One repeated retrieval condition had the three recall trials happen immediately, three times in a row. This condition, referred to as massed retrieval practice, is akin to repeating a new piece of information over and over in your head right after you experience it. Finally, in the last condition highlighted here, the students also practiced retrieving the words three times, but the repeated retrievals were spaced throughout the learning session. For instance, once a student correctly recalled the translation for mashua, the program moved on to other vocabulary words, but prompts to practice retrieval of the translation for mashua would pop up later on in the program. In this way, the retrieval opportunities were spaced throughout the learning session.
The key question in this research was, how well would students remember the vocabulary word translations in the long term? Figure 1 shows the proportion of translations that students remembered one week after the initial learning session.
Merely studying the words once without ever recalling them produced extremely poor performance (average recall was 1 percent, barely visible on the figure). Practicing until each translation was recalled once was much better. But what about the effects of repeated retrieval practice? Massed retrieval — repeating the translations three times immediately — produced no additional gain in learning. Repeated retrieval enhanced learning only when the repetitions were spaced, and indeed, the effects of repeated spaced retrieval were very large. In a single experiment, simple changes that incorporated spaced retrieval practice took performance from nearly total forgetting to extremely good retention (about 80 percent correct) one week after an initial learning experience (see also Karpicke & Roediger, 2008; Pyc & Rawson, 2010).
[...]
In one survey (Karpicke, Butler & Roediger, 2009), college students were asked to list the strategies they use while studying and to rank-order the strategies. The results, shown in Figure 2, indicate that students’ most frequent study strategy, by far, is repetitive reading of notes or textbooks. Active retrieval practice lagged far behind repetitive reading and other strategies (for a review of several learning strategies, see Dunlosky, Rawson, Marsh, Nathan & Willingham, 2013). A wealth of research has shown that passive repetitive reading produces little or no benefit for learning (Callender & McDaniel, 2009). Yet not only was repetitive reading the most frequently listed strategy, it was also the strategy most often listed as students’ number one choice, by a large margin.
I think the main attraction of repetitive reading is that it’s easier. Another consideration is that it seems to work on material that is of interest. When you watch a favorite movie over and over again, you start to memorize it. But when you watch a movie you hate over and over again, you zone out.
Vocabulary drill is a trap. You become a walking dictionary, with all the limitations of a dictionary. Much of the meaning of a word is in the context. A dictionary entry has no context at all.
Pimsleur language tapes work like this. Each new word or concept is repeated at declining frequency, just often enough that you’re forced to remember it. It’s a tremendous mental exertion, but there’s no faster way to start learning a new language.