McCall is conducting an experiment.Kids in group 1 get a treat if they clean up their room. Kids in group 2 don't get a treat for cleaning up their...

Dr. McCall is conducting an experiment. Kids in group 1 get a treat if they clean up their room. Kids in group 2 don't get a treat for cleaning up their room. Her results show that kids in Group 1 clean their room more often. Which type of reinforcement is being used in group 1?

punishment 

positive reinforcement 

negative reinforcement 

partial reinforcement