# 49. Manipulation of bias and heuristics in decision making ## 49.5. Methodology/Refinements/Sub-species ### 49.5.1. Ambiguity effect This is the propensity to avoid options for which missing information makes the probability seem "unknown". We tend to prefer options where we know the probability of a favourable outcome, rather than those options where we do not know the probability of a favourable outcome. For example, "I know that there is at best a moderate chance of my winning a local competition as the local players are good. There is a competition in the next town, but I do not know how good the players are there. Rather than 'risk it', I just enter for the local competition". A manipulator uses this tendency to force inaction or alternative decisions by depriving a victim of information on probable outcomes of particular options.