Time is a fundamental element of negotiation, often as a condition or situation faced by the negotiator (e.g. "I am under time pressure - I must sell my car today because I am leaving town tonight!"). Time can be strategic, used by negotiators to achieve an objective, typically an effort to evoke compliance, for example the exploding offer ("The job offer is only good until tomorrow at noon"). Time can affect many aspects of negotiation including basic negotiation processes and outcomes, choice of tactics, and basic psychological processes of emotion, cognition, and motivation. Time pressure often intensifies the prevailing motive, producing greater cooperation (e.g. concession making) and sometimes greater contention and disagreement. Some strategies of negotiation only occur with time (e.g. the black-hat/white-hat sequence), which suggests that 'timing' (knowing when to do something for an effect) is an important skill in negotiation. There are many aspects of time in negotiation that are ripe for empirical investigation.