Comment by sigmoid10

It certainly holds true for humans. The brain stores relational information in a sequential pattern that is not automatically reversible. One of the best examples is the alphabet. Everyone learns it in school, so the pattern A->B->C->... is trivial to recite for most people. Now, if I gave you a random letter to start with and asked you to to recite the remaining letters until Z, you'll probably find it is still pretty easy. But if I asked you to cite the letters backwards to A, most people would suddenly struggle with this task because they never learned or used the alphabet that way in school. You need to train specifically to link this kind of information backwards in your brain.