We need parallelism... "showed that X ... and that Y..."
This rules out A, B and C.
E. omits the "in childhood" part for the parents and introduces the wordy/awkward usage "likely to be perceiving behavior"... who's behavior?
D. Correct. We have parallelism thanks to "that children..." Grammatically correct usage of "more likely than X to do Y"
Pick D.
~Abhay
Believe those who are seeking the truth. Doubt those who find it. -- Andre Gide