Why does the lost child lose interest in the things that he had wanted earlier?

(CBSE SA-I, 2011)

The child was excited about many things in the fair but knew that if he would ask for anything from his parents their reply would be in the negative. He lost interest in everything that enticed him earlier when he realised that he was lost and his parents were nowhere to be seen. After realising that his parents were lost his only interest was in finding them and not in any of the other things of the fair.