Jarad wants to make sure that he does not raise children who are susceptible to the müller-lyer illusion. as such, he should

Jarad should raise his children in places where corners are not common.  

The Muller-Lyer illusion refers to an optical illusion comprising of a stylized arrow. When the volunteers are asked to put a mark on the figure at the center, they unvaryingly put it more towards the terminal of the tail. The illusion was invented by Franz Carl Muller-Lyer, a German sociobiologist, in 1889.