When consumers make unfavorable comparisons between the chosen option and the options forgone, they may feel post-decision regret or buyer's remorse. Consumers can also feel short-term regret when they avoid making a purchase decision, however this regret can dissipate over time. Through their experiences consumers can learn and also engage in a process that's called "hypothesis testing". This refers to the formation of hypotheses about the products or a service through prior experience or word of mouth communications. There are four stages that consumers go through in the hypothesis testing: Hypothesis generation, exposure of evidence, encoding of evidence and integration of evidence.