"Hannah loves when her aunt plays peek-a-boo. She misses her aunt each time she covers her face and goes away but is delighted when her hands move and she returns to play. Hannah is most likely in which of Piaget's stages of cognitive development?"

Sensorimotor

Explanation:

According to Piaget during the first two years of life, development focuses on sensorimotor schematics as the baby explores the world of objects. A wide variety of behavioral skills are developed and coordinated, but the development of verbal and cognitive schemas is minimal and poorly coordinated. The focus is on the  outstanding stimuli in the immediate "here and now" environment. However, as the baby develops, the physical actions that were initially reflexes are refined in controlled sensorimotor schemes; the duration of "out of sight, out of mind" attention is replaced by the knowledge of object permanence  and evidence of recall and search for them if removed; The initial understanding of cause and effect relationships that explain observable events develops, and the child begins to imitate the actions of others.

Sensorimotor stage

Explanation: Sensorimotor stage is  the first  stage of Piaget Cognitive development in children which usually  occurs from birth to 2 years. During this stage ,  infants are only  aware of what is immediately in front of them by focusing on movement sensations  and physical interactions within  their immediate environment which makes them to constantly experiment by  shaking or throwing things, putting things in their mouths, and learning through sequential type of plays etc and they acquire knowledge through sensory experiences through  reflexes and motor responses  and by manipulation of  objects.

Hannah who loves pee a boo with her aunt is most likely in the Sensorimotor stage of Piaget's stages of cognitive development

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

answer; earthquake;