Research suggests that this general tendency can change over time in response to key life events. Once trust is lost, by obvious violation of one of these three determinants, it is very hard to regain. Thus there is clear asymmetry in the building versus destruction of trust. Increasingly in recent times, research has been conducted regarding the notion of trust and its social implications: In her book, Barbara Misztal attempts to combine all notions of trust together. She describes three basic things that trust does in the lives of people: it makes social life predictable, it creates a sense of community, and it makes it easier for people to work together. In the context of sexual trust, Riki Robbins describes four stages. These consist of perfect trust, damaged trust, devastated trust and restored trust. In the context of information theory, Ed Gerck defines and contrasts trust with social functions such as power, surveillance, and accountability. From a social identity perspective, the propensity to trust strangers (see in-group favoritism) arises from the mutual knowledge of a shared group membership, stereotypes, or the need to maintain the group's positive distinctiveness. Despite the centrality of trust to the positive functioning of humans and relationships, very little is known about how and why trust evolves, is maintained, and is destroyed. One factor that enhances trust among humans is facial resemblance. Through digital manipulation of facial resemblance in a two-person sequential trust game, supporting evidence was found that having similar facial features (facial resemblance) enhanced trust in a subject's respective partner. Though facial resemblance was shown to increase trust, it also had the effect of decreased sexual desire in a particular partner. In a series of tests, digitally manipulated faces were presented to subjects to be evaluated for attractiveness within the context of a long-term or short-term relationship. The results showed that within the context of a short-term relationship, which is dependent on sexual desire, similar facial features caused a decrease in desire. Within the context of a long-term relationship, which is dependent on trust, similar facial features increased the attractiveness of an individual, leading one to believe that facial resemblance and trust have great effects on relationships. Interpersonal trust literature suggests that trust-diagnostic situations provide a means by which individuals can gauge or alter the level of trust in relationships. Trust-diagnostic situations refer to in trust or "strain-test" situations which test partners' ability to