Conclusion and Discussion

After reading of existing literature, we came up with the general hypothesis that birth order does, in fact, affect the extroversion or introversion of people. Therefore we set out to design our questionnaire according to extroversion tests. We also asked our participants the makeup of their sibling structure as well as their place in it. However, more in depth research after we had already posted the survey online found more specific results. According to Sulloway's research, both first-borns and later-borns possess extroverted traits, only in different areas. Our survey was sorely lacking in differentiating these said traits. Sulloway also proposed "direct sibling comparison", which asked respondents to rate themselves with regard to their siblings. Our survey lacked this form of comparison as we only asked participants to rate themselves. Also the sample size was too small, so when we divided them into categories, some were too small to be of use.

The results were quite surprising compared with our original, more general hypothesis as more than half of all participants had the "extroverted" result, with the other half split between "introverted" and "indistinguishable". However, after we discovered the flaws of our survey, we attempted to salvage the situation by analyzing the data with regards to gender and age gap: when this proved unfruitful, we compared the first-born results and second-born results. The general results are as follows:

• 
  Gender wise, the first-born child is more extroverted than the second-born in a family with two brothers. In a family with two sisters, however, the second-born tends to be more extroverted. In a family with siblings of opposite genders, there was no significant difference between first-borns and second-borns.
  
• 
  Regarding age gap, in a family where the age difference is between 0-2 years, the second-born is more extroverted. When the age difference is between 3-5 years, the first-born is more extroverted. There was no sufficient data for us to reach a conclusion regarding siblings whose age difference is 6 years or more.
  
• 
  If both gender and age gap are jointly analyzed, the results get interesting. Except for families with two brothers, all other kinds of gender structures showed the second-born to be more extroverted in 0-2 year age gaps and the first-born more extroverted in 3-5 year age gaps. Whereas in a two males makeup, both 0-2 years gap and 3-5 years gap showed the first-born to be more extroverted.
  

But despite the flaws of the questionnaire, we found other plausible explanations for such result that most of the participants report themselves as extroverted. According to Sulloway (1996), observer ratings are superior to self reports in terms of personality traits in birth order effects, because social desirability is a confounding factor in self-report responses. For example, some people are introverted, but they expect themselves to be extroverted and overrate their level of extroversion. Besides, first-borns are socially assertive and tend to pursue social approval. The expressions of their personality change in the different life courses. When they were at a college-age, they would project a gregarious figure, and thus the typical first-born personality, the introverted and conservative parts, are concealed.

As the current study relied exclusively on self reports from college students, we cannot confirm if observer ratings are more effective in capturing birth-order effects, nor can we examine how life transition affects first-borns. In addition, there are several limitations to this study. First, the samples were insufficient. Although gender and age gap are taken into consideration, the sample size of each category was imbalanced and too small to represent each group. Moreover, most of the participants were recruited from National Chengchi University （國立政治大學）, so the findings may not be strong enough to be generalized to every college student in Taiwan. Second, the definition of “extroversion” is ambiguous. We only consulted one scale of extroversion in our questionnaire, and neglected the possible credibility of other measures. The interpretation and definition to the questions might vary from person to person as well. Last of all, the prior research is lacked. As what has been mentioned above, we didn’t fully understand the context before posting the questionnaire. After doing further research, we found that there’re different dimensions to extroversion: first-borns are in the sense of dominance, and later-borns are in the sense of sociable. Lacking of this background knowledge is the main flaw to our questionnaire.

Due to the aforesaid limitations, we cannot draw any definite conclusions about the possible evolutionary aspect of birth order effects. However, this study was one of the very few studies that examined birth order effects on college students in Taiwan, and has taken confounding variables into account. For future study, it is recommended to increase the sample size and have balanced sample distribution. Besides, researchers should employ within-family design and ask participants to rate themselves as well as their siblings. To see if life transition affects birth order differences, the target participants can includes both college students and people who are taking a job (in a particular age range).

The influence of birth order on personality has been discussed for years but hasn’t reached a clear conclusion yet. Though this study had few innovative findings to the question, it offered some feasible way to improve in future study. Hopefully with more thorough researches and new methods, we can better understand the complex influence of birth order.
References

Chen, C. S. (2003). A study on the relations of family environment, personality, social skills, and academic achievement of junior high school students. [Abstract]. (Master’s thesis, National Changhua University of Education). Retrieved from

http://ndltd.ncl.edu.tw/cgibin/gs32/gsweb.cgi?o=dnclcdr&s=id%3D%22091NCUE0331012%22.&searchmode=basic#XXX

Chuang, C. H. (1994). The influence of birth order and parent rearing attitude on children social interest and personal adjustment. [Abstract]. (Master’s thesis, National Chengchi University). Retrieved from

http://thesis.lib.nccu.edu.tw/cgibin/gs32/gsweb.cgi/login?o=dstdcdr&s=id%3D%22B2002003807%22.&searchmode=basic

Connor, S., & Usborne, S. (2007, November). Are the family clichés true? Retrieved from

http://www.independent.co.uk/news/science/are-the-family-clichs-true-400882.html

Eysenck, H. J. (1973). Eysenck on extraversion. New York, NY: Halsted Press.

Gray, C. M. (1984). The relationship of birth order, sex, sibling sex and spacing between siblings to personality traits. New York, NY: Columbia University.

Ha, T. S., & Tam, C. L. (2011). A study of birth order, academic performance, and personality. Retrieved from

http://www.ipedr.com/vol5/no1/7-H00037.pdf

http://www.ssc.wisc.edu/wlsresearch/publications/files/_private/Hauser-Kuo-Cartmill_Birth.Order.and.Personality.Among.Adult.Siblings.pdf

http://ir.canterbury.ac.nz/bitstream/10092/3051/1/thesis_fulltext.pdf

http://www.hellomagazine.com/healthandbeauty/mother-and-baby/201209139262/birth-order-personality-traits/

http://www.cbsnews.com/2100-500172_162-511694.html

http://www.sulloway.org/BirthOrder-Sulloway-1999a.pdf

Sample Questionnaire

同學您好，我們是政大英文系的學生，目前在做一個針對子女出生序和個性的研究，需要您協助填答問卷。您提供的所有資料僅限於學術用途，也不會外流，請放心作答。感謝您的配合!

1. 
   請問您的性別是?
   

2. 
   您的年齡是?
   

3. 
   請問您是否為獨生子女？（指家中沒有其他兄弟姐妹）
   

4. 
   您家中兄弟姊妹的年齡？(ex:大哥24歲 二哥22歲 妹妹18歲)
   

5. 
   請問您的家庭形態屬於下列何種？
   

(   )單親家庭      (   )寄養家庭 (   )外籍配偶家庭 (   )其他

以下問題請盡量誠實回答，並以第一直覺的答案做答! （題目請以中文為主。）

1. 
   跟人們在一起我覺得很快樂。 (I feel happy when I am with people.)
   

2. 
   大部分的時間我喜歡獨處。 (Most of the time, I like to be on my own.)
   

3. 
   我寧可和一群人工作也不願獨自工作。 (I’d rather work with others than work alone.)
   

4. 
   我盡量不參加別人的談話。 (I try not to join in on others’ conversations.)
   

5. 
   我有很多親近朋友。 (I have many close friends.)
   

6. 
   我盡可能避免與別人交談。 (I try to avoid talking with others.)
   

7. 
   我獨處時比與別人共處時還快樂。 (I feel happier alone than with company.)
   

8. 
   當我覺得不舒服時，喜歡周圍有人安慰我。 (When I feel upset, I like to be comforted by others.)
   

9. 
   在他人眼中我不是一個善於社交的人。 (According to others, I’m not socially active.)
   

10. 
    我喜歡與人打交道。 (I like to socialize.)
    

11. 
    我不覺得自己需要朋友。 (I do not think I need friends.)
    

12. 
    參加社交活動我覺得很愉快。 (I feel happy in social events.)
    

13. 
    我喜歡把自己的想法藏在心裡。 (I don’t like to express my feelings.)
    

14. 
    我會努力去結交新朋友。 (I strive to make new friends.)
    

15. 
    您做事前是否傾向先計劃再行動？(Do you prefer action to planning for action?)
    

16. 
    您是否喜歡從事需具備果斷行動能力的工作？(Are you happiest when you get involved in some project that calls for rapid action?)
    

17. 
    交新朋友的時候，您是主動的那一方嗎? (Do you usually take the initiative in making new friends?)
    

18. 
    請問您行動時是否傾向於迅速、果斷？(Are you inclined to be quick and sure in your actions?)
    

19. 
    請問您會將自己歸類為活潑的人嗎？ (Would you rate yourself as a lively individual?)
    

20. 
    當您的社交活動受到限制時，您是否會感到不開心？ (Would you be very unhappy if you were prevented from making numerous social contacts?)