In multi-attribute decision making, the presence of the attraction effect or compro- mise effect is considered a form of irrational choice because these effects violate the principles of rational choice. These two context effects are similar in that they increase the choice share of a particular option, but the mechanisms by which they occur are believed to differ, owing to the different trade-off structures of the choice sets concerned. Previous studies have indicated that negative emotions and the strategies employed in decision making differ between the two context effects and that these effects correspond to Systems 1 and 2 of the dual process theory. In this study, focusing on trade-offs, we examined the mechanisms by which these two context effects occur, by experimentally manipulating cognitive resources and measuring negative emotion and eye movement in decision making. We attempted to increase and decrease these resources by using a glucose drink and a cognitive depletion task, respectively. Results showed that the at- traction effect increased and the compromise effect decreased in subjects with depleted cognitive resources compared to subjects with restored cognitive resources. Negative emotions were strongly aroused in the compromise effect. Eye tracking data showed that a non-compensatory decision strategy was used in the attraction effect context and that a compensatory decision strategy was used in the compromise effect. These find- ings suggest that reasoning systems and decision strategies are directed by differences in the trade-off structure of the choice sets, which ultimately lead to the occurrence of the above two context effects.