In this example, the type of selection that is expected to occur in the population is disruptive selection. Disruptive selection refers to changes in the population in which extreme values for a trait are favored over intermediate values. In this process, more individuals acquire a characteristic that is at either end of the distribution curve.
Based on the information provided within the question it can be said that in this scenario Kitty is demonstrating resistance to change. This occurs when an individual feels that change is coming and that it is a threat to them, whether it is physical or mental. Which in this scenario Kitty seems to get anxious and uncomfortable with change and believes that she will not be able to handle it.
