年齡對擇偶年齡與身高偏好門檻的影響

Aging Effect on Mating Preference Thresholds of Age and Height

有關擇偶年齡與身高的偏好及其性別差異的研究領域中，演化心理學中的性擇理論強調，男女因生育力的差異，為求子嗣傳佈的極大化，演化出不同的生殖策略與擇偶偏好，使得男女的年齡偏好隨年齡的增長而產生差異（Kenrick and Keefe, 1992）。人口學中的婚姻市場理論則認為，婚姻市場的大小將隨男女年齡增長而產生改變，男女因此面臨不同的擇偶機會縮小的壓力，因而調整其原先的擇偶偏好以增加結婚機會（South, 1991）。本文用台灣地區擇偶網站上的個人化資料，來分析年齡對擇偶的年齡與身高門檻的影響，以此檢驗這兩個理論的推論。本文實証顯示：（1）男性對異性的年齡上門檻與下門檻都設定的比女性低，而且男性年齡下門檻隨著年齡的增加而下移的幅度也比女性大。這部份印証了演化論（先天論）的看法。（2）女性三十歲以後隨年齡的增加而放寬身高下門檻。此結果亦部份印証了婚姻市場理論（調整論）的解釋。（3）男性年齡上門檻隨著年齡而調降，女性則微幅調升。本文發現結合上述兩理論所得出的「綜合推論」，比單獨的演化論或單獨的婚姻市場理論更能解釋此一男女差異的現象，先天論與調整論實有互補的可能。（4）令人意外而費解的發現是，男性隨著年齡的增加卻仍持續調升（更挑剔）身高下門檻。本文對此亦有深入的討論。

In the studies on mating preferences, evolutionary theory (sexual selection) suggests that gender differences in mating preference are based on genetic prerogatives (e.g., Kenrick and Keefe, 1992), and that different genders follow different patterns of changing mating preferences, accompanying increases of their ages. On the other hand, marriage market theory in demographics, suggests that aging men and women confront different marriage markets and different pressures from shrinking marital opportunities. Hence, they adjust their mating preferences accordingly (e.g., South, 1991). The present study examines the application of these two theories on gender difference of age threshold and height threshold, by using individual level data on the mate selection web site in Taiwan. The major findings are: (1) Men, in general, set much lower age thresholds than women do. Moreover, in aging, men lower the floor-age thresholds to a greater degree than do women. These confirm the predictions of evolutionary theory. (2) Women lower their height threshold when they are getting old, to compensate for their diminished marriage opportunities. These results only partly confirm the prediction of marriage market theory. (3) While aging men lower the ceilingage threshold, women raise the ceiling-age threshold. For this result, the combination of the two theories provides a better explanation than either evolutionary theory or marriage market theory does on its own. (4) To our surprise, men raise their height threshold when they are getting old. This neither confirms the prediction of evolutionary theory nor marriage market theory. The unexpected result will be discussed in detail.