CHAPTER FIVE
CONCLUSIONS
This study investigates effects of exposure frequency and contextual situations
on incidental learning of vocabulary. After the results and discussions of the study
have been presented in Chapter Four, this chapter covers a summary of major findings,
pedagogical implications for the EFL context in Taiwan, limitations of this study and
suggestions for future research.
5.1 Summary of the Findings
EFL senior high school students on a controlled setup in this study can acquire at
least receptive knowledge of vocabulary incidentally by reading texts for meaning and
demonstrate impressive retention for at least one month after receiving repeated
written exposures to the target words. In terms of the strength of word gains and
retention, word exposure frequency still plays an important role. As the number of
word exposures increased, there is a growing sign of word learning among the
learners. When words occur six times in the designated passages, vocabulary
acquisition is significantly observed; however, when words occur less than six times,
word gains are not significant and sometimes are even unpredictable. Those
unpredictable gains may result from the contamination of guesswork in the data,
forgetting as well as unlearning of words, and temporary declining performance
during lexical restructuring. Meanwhile, similar learning percentage of words under
four and six exposures is found between the present study and Rott (1999). From the
similarity, the study proposes four ranges of learning percentage for words under four
and six exposures and suggests contextual situations might be one of the factors
affecting how large these ranges are. In addition, although there is no
overwhelmingly significant difference in vocabulary learning between the two
contextual situations within each exposure frequency, it is speculated that reading
passages with inferential clues have the potential to facilitate learners at the formal
operational stage in vocabulary learning more and to reduce the rate of word meaning
forgetting to a greater degree. The advantages of inferential clues over explicit ones
are due to the possibility that processing words embedded in the former requires more
mental effort while target words embedded in the latter tend to be ignored. Finally,
although there is no statistically significant interaction between exposure frequency
and contextual situations, it is speculated that an interrelationship still exists between
these two factors in facilitating incidental vocabulary learning.
5.2 Pedagogical Implications for the EFL Context in Taiwan
Most Taiwanese students are used to learning new words by asking for an
accurate definition first. Even though the unknown words are well-defined in the
context, they would rather interrupt their reading either by looking them up in the
dictionary or by waiting for teachers’ explanations before they restore their confidence
in finishing the reading. Without doing so, they seem to be afraid that they can
neither fully comprehend the text nor increase their vocabulary size. Although
Goodman (1982) states “efficient reading does not result from precise perception and
identification of all elements, but from skill in selecting the fewest, most productive
cues necessary to produce guesses which are right the first time” (p. 34), it is still
common for teachers to preteach vocabulary in a reading text because they know it is
students’ familiar learning pattern and believe in the efficiency of such learning.
However, senior high school students should not abandon their inferring ability
to learn vocabulary because the study reveals that it is possible for them to learn
words incidentally from reading short and comprehensible texts. Interestingly, clues
requiring more inferring ability tend to facilitate students’ vocabulary acquisition
better than those surrounded with explicit definitions or synonyms. In other words,
giving students word definitions directly may deprive them of the opportunities to
deeply process the word meaning and lead to their inattentive browses at the target
words. Therefore, teachers should encourage students to infer word meaning from
context and design tasks that can enhance students’ mental processing of target words.
Considering EFL learners might have difficulty making use of contextual clues
especially in the early stage, teachers can guide them to start from words with familiar
concepts (Pulido, 2003; Ryder, 1986). Scholars also caution that authentic context
does not reliably assist learners in acquiring word meaning (Beck, McKeown, &
McCaslin, 1983; Laufer, 1997) and that incidental word learning will not happen if
learners can not infer word meanings from texts beyond their comprehensibility
(Ghadirian, 2002; Nation, 2001; Nation & Waring, 1997; Tran, 2006), so the
importance of text selections in promoting incidental learning can never be neglected
(Cho & Krashen, 1994). Additionally, when selecting textbooks for teaching context
skills, teachers can bear Slawson’s (1991) suggestions in mind: (a) introductions to
context units need better pictures to elicit students’ preexisting competence, (b) the
classification of contextual cuing systems should be expanded to a broader extent so
that students could develop their own cues, (c) processes and strategies for deriving
word meanings should be emphasized, (d) better guided practice should be provided
to serve as a bridge to content area materials, (e) questions for practice should be
generative and enhance students’ involvement with the text, and (f) context skills
should be integrated to help learners build a strong vocabulary and then improve
reading comprehension.
In addition, it is advisable for textbook writers to pay attention to the effects of
the repetitions of the target words and the suitability of contextual clues on learners’
incidental vocabulary learning. If clues for the target words are inferable, six
encounters of the words at least may beget significant vocabulary learning.
Moreover, the strength of learning will increase if contextual clues are mentally
demanding enough for the intended readers. Therefore, when selecting target words
for language use, writers can take these two factors into consideration.
Finally, like the approaches to vocabulary development proposed in many studies
(Brabham & Villaume, 2002; Horst, Cobb, & Meara, 1998; Jenkins, Matlock &
Slocum, 1989; Nation, 1982; Nation, 2001; Oxford & Scarcella, 1994; Paribakht &
Wesche, 1997; Prince, 1996; Pressley, 2002; Tekman & Daloglu, 2006; Tran, 2006;
Zahar, Cobb, & Spada, 2001), effective learning cannot just have one orientation.
Although the findings of the study support the advantages of incidental learning of
vocabulary, the aim of the study does not ask teachers to devote all the class time to
having students acquire words incidentally and to totally discard other teaching
methods such as direct instruction in helping students build massive vocabulary.
Instead, it still treats incidental learning as one of the methods complementary to the
entire language course. What needs to be stressed is that we should tell students they
have the potential to acquire words from exposures and have them experience how to
pick up words by reading in class, for studies indicate that one can improve the skill
of incidental word learning over time and practice or instruction of the necessary skill
will be expected to transfer to students’ ability to handle unknown words from context
(Buikema & Graves, 1993; Fraser, 1999; Goerss, Beck, & McKeown, 1999; Jenkins,
Matlock, & Slocum, 1989; Swanborn & de Glopper, 1999). After students accept
incidental learning as a means of enlarging their vocabulary and know how to acquire
language this way, they will enjoy the benefits of applying such experience in playing
Goodman’s (1982) ‘psycholinguistic guessing game’ when learning independently.
5.3 Limitations of the Study
Although words exposed six times are acquired significantly better than those
under any other exposure frequency, there are few significant differences among
words learned under exposures less than six and the two contextual situations also
make unsatisfactory statistical differences. Such nonsignificant results might be due
to the insufficient number of words used for each exposure frequency. Considering
the limited class time during the treatment sessions, the study could only test three
target words for each exposure frequency. In addition, to arrange a schedule for each
exposure frequency to have equal intervals, the study gave participants treatments
twice in a day most of the time during the sessions. Such intensive treatments in a
day might make participants tired of the treatments and less patient while they were
working on the required tasks. If more words had been used in each exposure
frequency and a less intensive treatment schedule had been implemented, there might
have been more significant differences found among words learned under exposures
less than six and between the two contextual situations.
5.4 Suggestions for Future Research
The study only adopts three target words without any typographical input
enhancement
6in each exposure frequency so if future studies can cover more words
and make these words more visually salient, maybe there will be more significant
differences found between word exposures fewer than six times and between
contextual situations. In addition, although the types of contextual situations within
each exposure frequency in the study do not constitute a significantly strong factor in
obtaining incidental increments of word knowledge, clue characteristics are still worth
investigating so other types of contextual situations can be tested in a similar
experiment design to see if the results will be different. Moreover, this study has
focused on how freshmen in a senior high school in northern Taiwan learn words
incidentally so future studies can recruit a different target pool of participants or
participants across different age groups and proficiency levels to determine whether
the conclusions here can be generalized to other students and to see if there is any
other significant difference. Additionally, since the study conducts the experiment
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