Beth is investigating the level of cognitive development of eight-month-old infants.
She is playing with her eight-month-old daughter in her living room at home.
Beth shows her daughter a ball and she reaches for it. Beth hides the ball behind
a cushion. Her daughter reaches behind the cushion to get the ball back.
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Explain what this shows regarding Beth's daughter's cognitive development.
You should refer to Piaget's Theory of Cognitive Development in your answer.