Those who had an imaginary friend tended to provide a richer narrative when asked to retell a story compared to those who did not. Specifically, their stories tended to include more descriptors, dialogue, character names, temporal-locative-causal details, and more verbatim recall. Interestingly enough, these two groups did not differ in their vocabulary ability, nor did they differ in their ability to comprehend stories.
Indeed. Little to add, only that OnFiction is rich with articles that look at reading from another angle (and not only reading and books), information on research (such as the above) and little psychology related stories.