To prevent the phonological similarity effect resulting from sound similarity between the keywords and the target words, changing the procedure of the keyword method might be a solution, i.e., encouraging semantic encoding of the target word (e.g., L1 translation) prior to phonological encoding. Traditionally, a keyword will be presented right after a target word. When participants accept a set of acoustically similar words, the phonological similarity effect may occur and therefore impair later retrieval.
According to Baddeley (2012), separating acoustically similar words with a dissimilar word (i.e., L1 translation or vivid illustration, which shows the semantic
meaning of the target word) may diminish or dissipate the phonological similarity effect and “show semantic and other long-term-memory-based effects” (Baddeley,
2012, p. 8). If the phonological similarity effect is inhibited by adjusting the sequence, confusion may be prevented and learners can further maintain long-term retention (semantic encoding).
The technique of changing the encoding sequence in the keyword method was tested with undergraduate students in Karpicke and Smith’s (2012) study. Karpicke
and Smith (2012) argued that the effect of repeated retrieval practice is more powerful
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than repeated study. Vocabulary learning was separated into two periods: study and recall. For the study period, the participants saw the target words and the definitions in pairs on a computer screen. For the recall period, only the target words appeared, and learners typed in the correct definitions. Each study period was followed by a recall period. There were six study/recall periods in total. All of the target words and the definitions were presented in pairs during the first study period. The participants were divided into three groups: drop, repeated study, and repeated retrieval practice.
Under the drop condition, a target word would be deleted once it was correctly recalled. That is, if the learners typed in the correct definition during the recall period, the target words would be removed during the following study/recall periods. The learners would not be tested or presented the definition of a correctly recalled target word again. Under the repeated study condition, all target words and their definitions appeared during all six study periods; the learners would keep seeing all target words and their definitions. The correctly recalled target words would be removed from the recall periods; the learners would still repeatedly see the correctly recalled target words and their definitions but would not be tested on them. Under the repeated retrieval practice condition, all the target words and their definitions would appear during all six recall periods. Thus, the learners would need to type in the definitions of
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all target words throughout the six recall periods. However, the learners would not see
the definitions of the correctly recalled target words again.
In Karpicke and Smith’s (2012) study, the keyword learners were provided a
keyword after the first successful recall of a definition. They were encouraged to form vivid mental images regarding the definitions of the target words. The control group was given only the target words and their definitions. The participants were informed that they were to take a one-week delayed test before the study trial. The results revealed no significant difference between the keyword group and the control group under drop, repeated study, or repeated retrieval conditions.
The keyword learners might not have outperformed the control learners
because of the ceiling effect. In their study, Karpicke and Smith (2012) suggested that at the end of the learning trial, both the keyword group and control group’s
performances reached a ceiling. That is, the participants in both the control group and the keyword group could correctly recall almost all of the definitions of the target words. Hence, no significant difference was found on the immediate recall test. On the one-week delayed test, no faster forgetting rate of the keyword groups over the control groups was found among any of the three conditions, which contradicts the claim that the keyword method has a faster forgetting rate than rote learning (Carney
& Levin, 1998; Wang et al., 1992). This outcome implied that when keyword learners
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were encouraged to do the semantic encoding prior to accepting the keywords, the forgetting rate might be less steep.
Though the technique of adjusting the encoding sequence was implemented in the study, the researchers did not compare the performance of the traditional teaching sequence (first keyword then definition) and that of the adjusted teaching sequence (first definition then keyword). Furthermore, though the researchers utilized the adjusted teaching sequence, they did not link the adjusted teaching sequence to the
issue of phonological similarity effect. This study aims to compare whether the participants’ performance improve when they are taught in the adjusted sequence. In Karpicke and Smith’s (2012) study, all keyword learners learned the vocabulary in the
adjusted sequence. The present experiment will examine whether adjusting the teaching sequence prescribed in the keyword method (i.e., first semantic then phonological) enhances and maintains students’ learning outcomes over time. If the students could learn better through such an adapted practice than through the traditional keyword method on the delayed tests, adjusting the sequence may be the solution to the retention problem commonly seen in keyword method research.
Namely, by preventing the phonological similarity effect, learners may be able to maintain the learning outcome of the keyword method.
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