幾乎所有動(dòng)物都擁有“個(gè)性”,，這會(huì)幫助它們應(yīng)對(duì)環(huán)境,，但是它們應(yīng)對(duì)環(huán)境以及其他動(dòng)物的程度有很大的差異。
Franz Weissing及其同事為這些個(gè)性如何隨時(shí)間而發(fā)展以及為何反應(yīng)高度敏捷并不總是最好的策略提供了一個(gè)進(jìn)化論的解釋,。他們的結(jié)果解釋了不同的個(gè)性如何可能在從魚到鳥類再到小鼠甚至人類等動(dòng)物身上出現(xiàn),。這組科學(xué)家利用一個(gè)簡單的數(shù)學(xué)模型，該模型代表了不同情況下的一系列可能的選擇和每個(gè)選擇的回報(bào),。他們證明了當(dāng)對(duì)環(huán)境反應(yīng)敏捷的這種特征罕見的時(shí)候,，它最有利，但是當(dāng)這種特征常見的時(shí)候,，它變得不利,。該結(jié)果解釋了為何反應(yīng)敏捷和反應(yīng)遲鈍的個(gè)體可以在一個(gè)群體里共存。
這組作者還發(fā)現(xiàn),，反應(yīng)敏捷常常是正反饋的,，而且隨著時(shí)間的推移而成本下降，這導(dǎo)致一些個(gè)體始終比另一些更加反應(yīng)敏捷,。因此自然選擇導(dǎo)致了一個(gè)種群中的兩個(gè)團(tuán)體,，其中一個(gè)在所有環(huán)境下都會(huì)對(duì)環(huán)境刺激做出反應(yīng)，而另一個(gè)在很大程度上對(duì)刺激的反應(yīng)遲鈍,。這組科學(xué)家提出這些反應(yīng)敏捷程度的模式可能導(dǎo)致其它特征的相關(guān)性,，例如大膽和侵略性，這為這樣的相關(guān)性為何常常見于動(dòng)物種群提供了一個(gè)解釋,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS published October 6, 2008, doi:10.1073/pnas.0805473105
Evolutionary emergence of responsive and unresponsive personalities
Max Wolf, G. Sander van Doorn, and Franz J. Weissing
In many animal species, individuals differ consistently in suites of correlated behaviors, comparable with human personalities. Increasing evidence suggests that one of the fundamental factors structuring personality differences is the responsiveness of individuals to environmental stimuli. Whereas some individuals tend to be highly responsive to such stimuli, others are unresponsive and show routine-like behaviors. Much research has focused on the proximate causes of these differences but little is known about their evolutionary origin. Here, we provide an evolutionary explanation. We develop a simple but general evolutionary model that is based on two key ingredients. First, the benefits of responsiveness are frequency-dependent; that is, being responsive is advantageous when rare but disadvantageous when common. This explains why responsive and unresponsive individuals can coexist within a population. Second, positive-feedback mechanisms reduce the costs of responsiveness; that is, responsiveness is less costly for individuals that have been responsive before. This explains why individuals differ consistently in their responsiveness, across contexts and over time. As a result, natural selection gives rise to stable individual differences in responsiveness. Whereas some individuals respond to environmental stimuli in all kinds of contexts, others consistently neglect such stimuli. Interestingly, such differences induce correlations among all kinds of other traits (e.g., boldness and aggressiveness), thus providing an explanation for environment-specific behavioral syndromes.
