1. Introduction

No one can underestimate the important role of vocabulary in learning a language. “If you spend most of your time studying grammar, your English will not improve very much. you will see most improvement if you learn more words and more expressions. You can say very little with grammar, but you can say almost anything with words!” (Thornbury, 2002). The strong relationship between vocabulary knowledge and reading comprehension has been determined and shown in both L1 (e.g., Anderson & Freebody, 1981; Beck et al., 1987; Nagy & Anderson, 1984) and L2 (August & Shanahan, 2006; Carlo et al., 2004; Carlo, August & Snow, 2005; Wagner et al., 2007). Given this relationship, EFL teachers need to adopt appropriate strategies to help learners learn as much vocabulary as possible from the reading materials in a text. One technique which can be employed in this regard is collaborative learning.

Collaborative learning involves an educational method which is concerned with learners' collective attempts at different levels to achieve a common goal (Bruner, 1985). As Johnson and Johnson (1994) maintain, the findings of studies show that learners in collaborative teams can achieve their goals at more advanced levels of thought, performing better in term of information retention compared to individuals who work individually. In fact, engaging in shared learning, students are provided with an opportunity to enter discussion with their peers, assuming responsibility for their own learning. According to Tino & Pusser (2006) when students are working in groups, they will be a part of a community whereby everyone will lend support to one another. This will provide the academic and social support in learning that students need. Seng (2006) found that collaborative learning would increase the chances of academic success. It is also found that when there are fun and interesting communicative activity in the classroom, the students enjoyed working in groups (Seng, 2006).

As a pre-reading strategy, the “tea-party activity” involving Reading, Writing and Rising Up by Linda Christensen (2000) who characterized it as an activity which instigates the lackluster readers to read. Christensen suggests that teachers and learners use an appealing passage from the novel or writing a small narrative from the perspective of one of the characters. She makes it clear that her purpose is to make reading intriguing, posing questions for the purpose of making learners familiar with the characters prior to engaging in reading. “Through using the first person for the characters, learners can get into the character’s head more easily” (Christensen, 2000). In the same vein, Jim Burke (2007) asserts that learners need to react to texts in writing. According to Burke (2007), learners enhance their reading skill through focusing on specific sections of the text. This would improve their interpretive or analytical capability. While engaging in the tea party, learners are requested to have a closer look at the relationships between the characters while they may not have any real interactions during the story in the book. According to Beers (2003) tea party strategy has 9 main steps: 1) Creating cards 2) Having students to socialize 3) Returning to small groups 4) Recording predictions 5) Sharing “we think” statements 6) Reading the selection 7) Reflection & discussion 8) Modifications for content area selections 9) Extensions. Learners are allowed to consider portions of the text prior to reading it through the use of this strategy. It also encourages the learners to actively participate in the tasks, listening attentively with ability to get up and move around the classroom. Moreover, this strategy provides the learners with an opportunity to predict what would happen in the text. This is possible through making inferences, working out the causal relationships, comparing and contrasting, practicing sequencing constructively, and drawing on background knowledge (Anderson, 1999). Despite the fact that research has used and examined collaborative learning models in L2 classrooms, little research has been carried out on the impact of the use of the tea-party strategy on vocabulary learning. L2 learning professionals and instructors have turned a blind eye to many potentialities of collaborative learning, in particular, its contributions to vocabulary learning. As already mentioned, the present study seeks to find the possible impact of tea-party strategy on extrovert-introvert students’ vocabulary achievement. In line with the objectives of the present study, the following research question was formulated:

Q: Is there a significant difference between the impact of tea-party strategy on introverted and extroverted EFL learners’ vocabulary achievement?

2. Method

Regarding the nature of the research, the design of this study is quasi-experimental since it made use of two extroverted and introverted groups. More specifically, the design of the current study was pretest-posttest comparison design. This research consisted of an independent variable which was tea-party strategy, while the dependent variable was vocabulary achievement. Moderator variables were extroversion and introversion. Only gender and proficiency level were the control variables of this study.

2.1. Participants and Procedure

2.1.1. Participants

The participants of the present study were 90 Iranian female intermediate EFL learners studying at Girls Shokuh language school. The age range of the participants was from 14 to 30 years old. Their first language was Persian and none of them had ever experienced living in English speaking countries.

2.1.2. Procedure

Before the starting of the treatment all students were given Eysenck Personality test (EPI), this test categorized them into two subgroups (47 extroverts and 43 introverted). After the administration of EPI a Preliminary English Test (PET) was administered to these 90 learners, then 60 participants whose scores in PET test fell one standard deviation above and below the mean were chosen. So among these 90 learners two Groups of Extroverted and Introverted which achieved the PET test, each including 30 learners, were selected as two experimental groups. The tea-party instruction lasted for 12 sessions. Preliminary English Test was also piloted among 30 intermediate EFL learners with almost the same language proficiency level and characteristics of the target group who took the tests later; this group took the EPI and vocabulary researcher-made test as well. In the pilot group there were 16 extroverted and 14 introverted. In order to rate the speaking and writing sections of the PET, two expert English instructor cooperated with the researcher. The inter-rater reliability of the two raters established as well. For the empirical investigation of the research question, the following null hypothesis was formulated:

H0: There is no significant difference between the impact of tea party strategy on introverted and extroverted EFL learners’ vocabulary achievement.

2.2. Statistical Analysis

In order to answer the aforementioned research question and investigate the null hypothesis of the present study, a number of statistical analyses were conducted. The data analysis of this study is comprised of two series of calculations: Descriptive statistics and inferential statistics. The descriptive statistics (including item discriminations and standard deviations) of PET and vocabulary tests were measured to homogenize items and also to estimate the internal consistency through using Cronbach Alpha. Inferential statistics are used to test the null hypothesis of the study. A paired sample t-test was used to search whether tea-party had any significant effect on extroverted and also introverted EFL learners’ vocabulary achievement, furthermore the independent t-test was utilized to investigate whether tea-party had any significant differential impact on extroverted vs. introverted learners’ vocabulary performance. In addition the inter-rater reliability of two raters’ scores on PET writing and speaking sections was calculated through spearman correlation.

3. Results and Discussions

As it was said before, in order to homogenize the participants PET was piloted to a Sample Group of 30 learners with almost the same characteristics of the main group. After calculating item facility, item discrimination and reliability of the test, the analysis indicated that there were no items that were removed. The reliability of the Sample PET turned out to be 0.832 which was an acceptable index. After ensuring the PET’s reliability, the test was administered to 90 students, the reliability of the PET in this actual administration was also calculated, index of 0.89 reassured the researcher for the reliability of this test. So 30 extroverted learners from 47 extroverted and 30 introverted learners from 43 introverted students who took the PET whose scores fell one standard deviation above and below the mean were selected as the main participants of this study. The descriptive statistics of the groups’ PET scores prior starting the treatment was calculated and it shows that the tests’ mean scores for Extroverted and Introverted groups turned out to be 41.53 and 44.23. As the ratio of skewness/Std Error of skewness for both groups was within the range of -1.96 and +1.96, the researcher was sure about the normality of the distribution of scores. Therefore, the researcher conducted an independent samples t-test to see whether a significant difference existed between the two experimental groups language proficiency prior to the treatment. After conducting the t-test, the results (t =0.104, p = 0.917 > 0.05) indicated that there were no significant difference between the proficiency levels of the two groups at the outset. Hence, the researcher could rest assured that any probable differences at the posttest level would be attributed to the effect of the instruction.

In order to demonstrate any possible significant difference in the performance of the introverted group and extroverted group and to verify the null hypothesis of the study, the researcher conducted a paired sample t-test between the pretest and posttest of the extroverts and between the pretest and posttest of introverts separately and then conducted an independent t-test between posttests of the extroverts and introverts. Prior to that, the normality of the distribution of scores within each group had been checked.

Table 1. Paired Sample Statistics of the Extroverted Group pretest and posttest

Table 2. Paired Sample t-Test of the Extroverted Group pretest and posttest

As the tables 1 and 2 indicate, the significance achieved is smaller than our significance level at .05. This means that the presupposed null hypothesis is rejected meaning that the difference observed between sample means was large enough to be attributed to the differences between the population means and therefore not due to sampling errors. It also shows that based on the results achieved, there is an improvement for the means of vocabulary achievement of extroverted group in comparison to its pervious stage.

Table 3. Paired Sample Statistics of the Introverted Group pretest and posttest

Table 4. Paired Sample t-Test of the Introverted Group pretest and posttest

As the tables 3 and 4 indicate, the significance achieved is smaller than our significance level at .05. This means that the presupposed null hypothesis is rejected, meaning that the difference observed between sample means was large enough to be attributed to the differences between the population means and therefore not due to sampling errors. It also shows that based on the results achieved, there is an improvement for the means of vocabulary achievement of introverted group in comparison to its pervious stage.

Table 5. Independent Sample t-test of the Extrovert and Introvert Groups

Table 5 above indicates with the F value of .001 and the p value of .970, being greater than .05, the variances between the two groups were not significantly different. Hence, running an independent sample t-test was legitimized for comparing the means of posttest scores of the extroverted group (M=18.7, SD =2.30) and the introverted group (M=17.366, SD=2.14). The results (t=-2.371, df =58, p =.021 < .05, two-tailed) indicated that there was a significant difference between the mean scores of the two groups at the posttests. It can thus be concluded that the null hypothesis was rejected, meaning that based on the comparison between the means scores of introverted group and extroverted group the extroverted group outperformed the other group. The means score of extroverted group was 18.7 and the means score of introverted group was 17.36; so the difference observed between sample means was large enough to be attributed to the differences between the population means and not due to the sampling error or chance.

The results of the study were consistent with those of earlier studies which compared other Cooperative learning methods against lecture or independent styles of instruction (Slavin, 1991). The respondents in the experimental group conducted by Slavin also gained greater achievement than that of the control group. The finding also proved that Cooperative learning as well as group work could increase individual students’ participation in terms of conversational turns. This finding was also consistent with the finding of Khairiyah and Mimi (2003), who discovered that active learning promotes better understanding of the respondents, yielding better results for the students.

Regarding the question of the study, the data statistical analysis revealed that improvement occurred in the vocabulary achievement of both groups of extroverted and introverted learners in comparison to their previous stage. Moreover, based on the statistical analysis of the data which was done for the comparison between the posttest of the two groups of extroverted and introverted, it could be concluded that extroverted learners have shown more improvement. The reason for the better performance of extroverted group in comparison to introverted group might be due to the fact that “extroverts naturally tend to go after an external stimulation to achieve an optimal level” (Eysenk, 1985); and since they were provided with a situations in which they were allowed to talk about what they think and socialize with their peers, this might have helped them to retain and remember the words better. It could be argued generally that introverted learners do not tend to participate in different processes and tasks as much as extroverted learners, so the learners’ styles can be a determining factor in functioning of the techniques in teaching-learning context. As a final remark it has to be noted that the findings of this study should be generalized with caution due to limitation which existed in the context where the study took place. The researcher did not have any male participants in her study since she was teaching in Girls school. Therefore gender was controlled and the findings of this study cannot be generalized to the contexts where the participants are male or co-education contexts.

4. Conclusions

The outcome of the posttest and pretest analysis clarified that using tea-party strategy has significant effect on extroverted and introverted EFL learners’ vocabulary achievement both in comparison to their previous stages and also in comparison to each other (Extroverted group outperformed the introverted group). That is to say that the use of tea-party strategy during instruction significantly increased learners’ vocabulary knowledge. Although this study was limited in duration and scope, the results clearly support earlier research on cooperative learning and the effect of tea-party in the domain of vocabulary achievement which found that tea-party techniques have a positive impact on vocabulary knowledge and usage of learners and also establishes enjoyable class time period and group work. As the present study focused on the effect of tea-party strategy on vocabulary achievement of extroverted and introverted EFL learners; the subsequent suggestion is to investigate the role of tea-party strategy in learning language functions and grammar, it is also recommended to investigate the role of tea-party strategy on students’ other skills such as speaking and listening.