do we make decisions or "judge"

Do humans make decisions or make a "judgement call" based on their intelligence about a subject? or their ignorance.

They make a judgement based on their thoughts and beliefs which have been moulded over time by their peers and experiences, Intelligence is really unquantifiable.

i think it depends really on past experiences

I don't think you can make a broad statement like that about 'humans'.
Many people make unwavering decisions based on presumption and ignorance, thats why it's important not to close your mind to new information.
ESPECIALLY when it contradicts your beliefs.