In evolutionary terms, what does "directional selection" aim to favor?

Directional selection is a mode of natural selection that favors one extreme phenotype over others in a given population. This leads to a shift in the population's traits in a specific direction, thereby increasing the frequency of that favored phenotype over time. For instance, if larger body size is advantageous for survival and reproduction in a specific environment, individuals with larger sizes will be more likely to survive and reproduce, gradually making the population predominantly exhibit larger sizes.

In contrast to averaging traits or stabilizing existing characteristics, directional selection actively promotes change by selecting extreme traits that confer greater advantages in a particular context, such as environmental shifts or changes in available resources. This can result in significant evolutionary changes, as the selected trait becomes increasingly prevalent in successive generations.