towards the ingroup may be adaptive if a hostile outgroup threatens to kill the entire ingroup. Reciprocal altruism. See also Reciprocity (evolution). Direct reciprocity. Research shows that it can be beneficial to help others if there is a chance that they can and will reciprocate the help. The effective tit for tat strategy is one game theoretic example. Many people seem to be following a similar strategy by cooperating if and only if others cooperate in return. One consequence is that people are more cooperative if it is more likely that individuals will interact again in the future. People tend to be less cooperative if they perceive that the frequency of helpers in the population is lower. They tend to help less if they see non-cooperativeness by others and this effect tend to be stronger than the opposite effect of seeing cooperative behaviors. Simply changing the cooperative framing of a proposal may increase cooperativeness such as calling it a "Community Game" instead of a "Wall Street Game". A tendency towards reciprocity implies that people will feel obligated to respond if someone helps them. This has been used by charities that give small gifts to potential donors hoping thereby to induce reciprocity. Another method is to announce publicly that someone has given a large donation. The tendency to reciprocate can even generalize so people become more helpful toward others in general after being helped. On the other hand, people will avoid or even retaliate against those perceived not to be cooperating. People sometimes mistakenly fail to help when they intended to, or their helping may not be noticed, which may cause unintended conflicts. As such, it may be an optimal strategy to be slightly forgiving of and have a slightly generous interpretation of non-cooperation. People are more likely to cooperate on a task if they can communicate with one another first. This may be due to better assessments of cooperativeness or due to exchange of promises. They are more cooperative if they can gradually build trust, instead of being asked to give extensive help immediately. Direct reciprocity and cooperation in a group can be increased by changing the focus and incentives from intra-group competition to larger scale competitions such as between groups or against the general population. Thus, giving grades and promotions based only on an individual's performance relative to a small local group, as is common, may reduce cooperative behaviors