# 49. Manipulation of bias and heuristics in decision making ## 49.5. Methodology/Refinements/Sub-species ### 49.5.46. Optimism bias This is the inclination to be over-optimistic, overestimating favourable and pleasing outcomes (see also wishful thinking, valence effect, positive outcome bias). A manipulator can take advantage of over-optimism to alter a victim's behaviour or decision making.