This is bias where there is a tendency to reach a conclusion based on the first stimuli we get. This tendency may also be attributed as an energy/saving behaviour. Once we think about out first conclusion, we have given it more ammunition. This can lead to 2 things. Firstly, we will stop accepting newer ideas and viewpoints into our thinking. Secondly, we try to reason out why the first conclusion is the right one. A mental routine to counter this bias is to acknowledge this and to think inversely. Where you assume that the first conclusion HAS to be wrong. This will allow us to ask more objective questions rather than settling in with the first conclusion.
An example, we see a shelf in the supermarket that is empty. Our first conclusion might be that the particular product is currently trending and it is being “over-bought”. But there could be other explanations as well. Maybe the product was recalled due to some defect. Or the shelves were emptied as they were not being sold at all and it was closing in on its expiration date.