Fitness is measured as the number of offspring 2. Digitally added chucks resulted in females preferring the added chucks to the lone whine. When artificial tails are appended to the platyfish, females prefer the appended conspecific males to the short tailed conspecific males. This shows another pre-existing preference. Assume that males have short or long tails and that females prefer long tails or do not assess potential mates.
Individuals possess genes for traits and preferences but only exhibit the character of their gender.
The results would be that males with long tails have a greater reproductive success due to the female preference. Offspring will be more likely to have genes for long tails and the long tail preference. A positive feedback is established and both trait and preference are magnified. 8.5.1 Genetic correlation of trait and preference -Empirical studies have examined patterns of geographical variation in trait and preference or select on a trait and measure a correlated evolutionary response in the preference. Sons' intensity correlated with the fathers' and daughters of red males preferred red males and daughters of dull males showed no preference.