The cohesion of a group refers to the level of unity, cooperation, and trust among its members. When a group is cohesive, its members are more likely to work together effectively and make better decisions collectively. This is because cohesive groups tend to have open communication, shared goals, and mutual support, which leads to more diverse perspectives and better problem-solving. Therefore, it can be concluded that the cohesion of a group plays a crucial role in determining whether individual or group decision making yields the best results.