Which person introduced the concept of reinforcement into behaviorism?

In a study of selective attention, the irrelevant information interfered with sorting ability for all age groups, but older children were ____________________ than younger children

Fill in the blank(s) with correct word

Dr. Marcy is conducting an observational study that compares a group of people who have a specific disease to a control group of people who do not have that disease. What type of study is this?

A) Prospective B) Case-control C) Retrospective D) Both B and C