近年來,國內教育政策著重於英語教育之推展,以因應國際化之局勢。研究顯示,雙語除了語言應用的益處外,亦具提升認知表現之優勢,包括提升執行功能、創造力等人類基礎的認知能力與最高的心智表現。然而,過去研究對雙語內涵的界定不一,創造力表現僅採用單一面向的評量,且國內雙語研究多集中於英語學習態度、興趣與成效方面,較少探討雙語的認知優勢。本研究即探討國內大學生國英雙語平衡程度對執行功能以及兩類創造力的影響。本研究招募109位來自15所大學的參與者,進行語言使用經驗、數字判斷作業(執行功能中的轉換能力)、報紙的不尋常用途(開放式創造力)、中文詞彙遠距聯想測驗(封閉式創造力)的評量,另測量或蒐集其智力、開放性人格特質以及社經地位作為控制變項。相關分析結果顯示,雙語平衡程度與轉換能力、開放式創造力指標呈顯著相關,雙語使用愈平衡,轉換能力與開放式創造力愈佳;區分高、中、低雙語組進行共變數分析顯示,高、低雙語組的封閉式創造力表現高於中雙語組,呈「U」型趨勢;分析亦發現,開放性人格特質可調節雙語與開放式創造力之關係。本研究結果呼應了國內英語教育政策的可能認知獲益,引發未來許 多議題深入探討的方向,具理論上與應用上的意義。 Background In response to internationalization, recent domestic education policies in Taiwan have begun to focus on promoting English education. According to research, bilingualism not only improves language proficiency but also cognitive performance. For example, it enhances executive function and creativity, which are fundamental cognitive capabilities and the highest mental performance. Nevertheless, several problems in the area of bilingualism and creativity remain to be addressed. First, research has provided inconsistent definitions of what bilingualism entails. According to the proposed concept that bilingualism improves cognitive abilities through enhancement of executive function, which occurs when an individual regularly practices and switches between two languages, balanced bilingualism can be considered an appropriate measure of bilingualism. Second, creativity has predominantly been evaluated unilaterally in previous studies, typically by using open-ended creativity measures. However, open-ended (involving the amount of creativity and without a single, correct answer) and closed-ended (involving creative and correct answers) creativity involve distinct processes, exhibit different associations with various psychological factors, and have unique physiological bases. Therefore, these two types of creativity must be distinguished. Third, although previous bilingual studies in Taiwan have predominantly focused on attitudes toward, interest in, and the effectiveness of English language learning, they have rarely explored the cognitive benefits of bilingualism. In this study, we investigated the effect of balanced bilingualism on executive function and two types of creativity among university students in Taiwan. Method A total of 109 students from 15 universities in northern Taiwan were included in the study. Students were recruited to measure their language usage experience and executive function shifting (switching) ability. Both the Unusual Uses of Newspapers Test (open-ended creativity) and Chinese Word Remote Associates Test (closed-ended creativity) were used to evaluate the creativity. Data were also collected on the students’ intelligence, openness personality traits, and socioeconomic status, which were included as control variables. The students were asked to report the total amount of time that they spent using Mandarin and English on a daily basis. Subsequently, the balanced bilingual index was calculated by the absolute value of the difference between the student’s time using the two languages divided by the sum of the language usage time. A smaller index indicated a higher degree of balanced bilingualism. As a next step, a number identification task was employed to evaluate each student’s shifting ability. In each trial, two colored numbers (green and purple) were presented, and the students were asked to identify whether the green number was even or odd. After 40 trials, the identification rule was changed, and the students were presented with a different set of colored numbers (green and gray). They were asked again to identify whether the gray number was even or odd. This new identification rule was implemented for 20 trials. The difference in the average reaction times between the 10 trials before and after the identification rule was changed was used to index each student’s shifting ability (switching cost), with a smaller cost indicating higher performance. The Unusual Uses of Newspapers Test was used to measure open-ended creativity. In this test, the students were asked to think of as many unusual uses for newspapers as possible. Their responses were coded following a standard instruction manual. The fluency index indicated the total number of ideas generated, the flexibility index indicated the number of ideas spanning different use categories, and the originality index indicated the uniqueness of each idea. Three scores were standardized for each student and summed to obtain a total score. The Chinese Word Remote Associates Test was used to measure closed-ended creativity. In this test, the students were presented with three words and were asked to think of one correct word that separately related to each of the three words. The total number of correct responses for 30 sets of words was used as the closed-ended creativity index. Intelligence was measured using Raven’s Advanced Progressive Matrices, and openness personality and socioeconomic status were evaluated using self-report measures. The total experiment time was approximately 1 hour for each student. Results According to our correlational analysis results, the degree of balanced bilingualism significantly correlated with shifting ability, indicating that a higher degree of balanced bilingual usage was associated with a stronger shifting ability and higher executive function. In addition, the degree of balanced bilingualism significantly correlated with various indices of open-ended creativity, including fluency, flexibility, originality, and total scores. By contrast, the degree of balanced bilingualism did not correlate with closed-ended creativity performance. Furthermore, because the confounding variables (intelligence, openness personality, and socioeconomic status) correlated with balanced bilingualism and, to some extent, with open- and closed-ended creativity, we conducted analyses of covariates among the high (n = 38), intermediate (n = 34), and low (n = 37) bilingual groups, with balanced bilingualism included as the independent variable; shifting ability and openand closed-ended creativity included as the dependent variables; and intelligence, openness personality, and socioeconomic status included as the control variables. The results indicated that the high bilingual group outperformed the low bilingual group in terms of shifting ability, indicating a significant increasing trend. After the covariates were controlled for, the differences between the three groups in terms of open-ended creativity indices became less significant. Only the indices of flexibility and total scores exhibited marginally significant increasing trends. Group comparison revealed that both the high and low bilingual groups exhibited higher performance in terms of closed-ended creativity compared with the intermediate bilingual group, exhibiting a significant U-shaped trend. When we conducted hierarchical regression analyses with open-ended creativity included as the dependent variable, we discovered a significant interaction effect between balanced bilingualism and openness personality. Openness personality moderated the association between bilingualism and open-ended creativity. That is, individuals with stronger openness attitudes toward new experiences benefited more from bilingualism and exhibited higher open-ended creativity performance. Conclusions This study revealed several key findings, and its results have several implications. First, with balanced bilingualism serving as the bilingualism index, we obtained results that supported previous findings on the association between bilingualism and executive function as well as those on the association between bilingualism and open-ended creativity. The results we obtained using the balanced bilingual index were significant, indicating this index is appropriate for measuring bilingualism. Second, open- and closed-ended creativity involve different processes, and our results revealed distinct associations between open- and closed-ended creativity and bilingualism. A U-shaped trend for the association between bilingualism and closed-ended creativity was observed between the three groups, and this trend can be explained by bilingual threshold theory, which indicates that fluency plays a role in the cognitive benefits of speaking both English and Mandarin. Further research is required to determine whether open- and closed-ended creativity are associated with different bilingualism thresholds. Third, our results indicated that openness personality played a moderating role in the association between bilingualism and open-ended creativity. Nevertheless, whether other variables interact with bilingualism and creativity, particularly closed-ended creativity, is a topic that warrants further research. On the basis of the results of this study, this finding offers suggestions for fostering bilingualism. For example, personality factors should be considered when second language education is being implemented or when interventions aimed at enhancing different forms of creativity through tailored training protocols related to bilingualism are developed. In conclusion, our findings support the potential cognitive advantages of English language education policies in Taiwan. They also reveal new avenues for research and have both theoretical and practical implications that can inform the development of educational strategies and policies.