There are a couple examples in caves that really help us understand how delicate the characters frame of mind are. In chapter fourteen of A Passage To India, Adela mistakes a tree stump for a snake. She easily confuses the entire group, and even after she corrects herself. Dr. Aziz reanimates the confusion by classifying it as a black cobra. Even though Adela corrects herself, Aziz and the rest of the group persist, and in the end they discover their confusion was in vain. Later in the same chapter Forster describes echoes that go "boum". He describes them as so rattling that they "quiver up and down the walls until it is absorbed by the roof". Snakes and worms coil up, and i think it is because these echoes scare them. Being in a place like a narrow corridor, where the basic design of it causes such profound echoes, can be disturbing for anyone. I think Forster uses this passage to describe how much rattling is going on in the characters heads.Proof of this can be found later, when Adela separates herself from Aziz, and makes everyone think she has been assaulted by Aziz. Adela uses Aziz as an escape from Ronny. Aziz is Indian, and a good host, but Adela sees that as an easy way to fool the others.