Answer: Animism
Step-by-step explanation: Animism is defined as the belief usually followed by the children at the early stage in which they believe that inanimate objects tend to have the feelings and human activities .the inanimate objects are usually toys , dolls, teddy bears etc.
According to the cognitive development of the children in early childhood , they start to have such tendency to believe in animism and as they grow older (near 7 years to 12 years) they realize that life is present in living beings like human, tree animals etc.
Thus, Olivia is also indulged in the animism concept at the age of 3 years regarding her toy train.