Foraging behaviour is shaped by the learned preference, thus causing apostatic selection and conferring a fitness benefit on the rare prey morphs. From this, it was concluded that search image formation and adaption is the mechanism that causes the most common prey type to be most easily distinguished from its environment, and thus be eaten more frequently than rarer types. Experimental evidence Various types of experiments have been done to look into apostatic selection. Some involve artificial prey because it is easier to control external variables in a simulated environment, though using wild specimens increases the study's external validity. Often a computer screen simulation program is used on animals, such as birds of prey, to detect prey selection. Another type looks into how apostatic selection can act on the predator as well as the prey, as predator plumage polymorphism can also be influenced by apostatic selection. They hypothesized that a mutant predator morph will become more abundant in a population due to apostatic selection because the prey will not be able to recognize it as often as the common predator morph. Apostatic selection has been observed in both humans and animals, proving that it is not exclusive to lower organisms, and the cognition it requires is applicable to all organisms which display learning. Though a lot of this work has been experimental and lab controlled, there are some examples of it happening in both wild specimens and in the natural habitat of the species. In hawks, almost all polymorphism is found on their ventral side. It allows for less common coloration to be favored since it will be recognized the least. Polymorphism is established by foraging strategies, creating opportunities for apostatic selection. Because of the different morphs and the varying selection on them, prey perception bias maintains prey polymorphism due to apostatic selection. Apostatic selection can be reflected in Batesian mimicry. Aposematism and apostatic selection is used to explain defensive signaling like Batesian mimicry in certain species. A paper by Pfenning et al., 2006 looks into this concept. In allopatric situations, situations where separate species overlap geographically, mimic phenotypes have high fitness and are selected for when their model is present, but when it is absent, they suffer intense predation. In Pfenning's article it was suggested that this is caused by apostatic selection because strength of selection is higher on the mimics that have their original model present. In Batesian