The average ages at which an individual displays certain abilities are known as

The average ages at which an individual displays certain abilities are known as developmental norms .

Developmental norms is a phrased used to describe milestones in development wherein an individual displays physical, social, emotion or intellectual learned patterns of behavior or abilities.

Explanation:

Learning to walk is a physical developmental norm.

Learning to speak or read is an intellectual developmental norm.

Learning to interact in a positive manner with people within one's peer group is a social developmental norm.

Learning to express emotions in a constructive manner (anger) is an emotional developmental norm.