Department of Biology, University of Vermont, Burlington, VT 05405-0086, USA.
Evolution. 2013 Jun;67(6):1539-48. doi: 10.1111/j.1558-5646.2012.01821.x. Epub 2012 Nov 8.
When Hamilton defined the concept of inclusive fitness, he specifically was looking to define the fitness of an individual in terms of that individual's behavior, and the effects of its' behavior on other related individuals. Although an intuitively attractive concept, issues of accounting for fitness, and correctly assigning it to the appropriate individual make this approach difficult to implement. The direct fitness approach has been suggested as a means of modeling kin selection while avoiding these issues. Whereas Hamilton's inclusive fitness approach assigns to the focal individual the fitness effects of its behavior on other related individuals, the direct fitness approach assigns the fitness effects of other actors to the focal individual. Contextual analysis was independently developed as a quantitative genetic approach for measuring multilevel selection in natural populations. Although the direct fitness approach and contextual analysis come from very different traditions, both methods rely on the same underlying equation, with the primary difference between the two approaches being that the direct fitness approach uses fitness optimization modeling, whereas with contextual analysis, the same equation is used to solve for the change in fitness associated with a change in phenotype when the population is away from the optimal phenotype.
当 Hamilton 定义包容性适合度的概念时，他特别试图根据个体的行为及其行为对其他相关个体的影响来定义个体的适合度。虽然这是一个直观上很有吸引力的概念，但在核算适合度并将其正确分配给适当的个体方面存在问题，这使得这种方法难以实施。直接适合度方法已被建议作为一种模拟亲缘选择的方法，同时避免这些问题。Hamilton 的包容性适合度方法将个体行为对其他相关个体的适合度效应分配给焦点个体，而直接适合度方法将其他个体的适合度效应分配给焦点个体。情境分析是作为一种在自然种群中测量多层次选择的定量遗传方法而独立发展起来的。尽管直接适合度方法和情境分析来自非常不同的传统，但这两种方法都依赖于相同的基本方程，这两种方法的主要区别在于，直接适合度方法使用适合度优化建模，而在情境分析中，相同的方程用于求解当种群偏离最优表型时，表型变化与适合度变化之间的关系。
