帮我改写下这句英文短语.
motivation depends on individuals’ mental expectations about their ability to perform tasks and receive desired reward
动力取决于个人对于其执行任务和接受期望回报的能力的心理预期.
这应该是 Expectancy Theory 期望理论.
再问： 我知道意思，我是希望把上面的短语，重新改写一下。谢谢
再答： Men always expect to satisfy certain needs and receive desired reward. This kind of expectation always motivates men's actions. 不知道这改写了做什么用。。。- -（好奇……）
再问： 我也论文，之前那句是原句。。必须改写。。
再答： 以下中文是引用的，略作了修改，英文是翻译的。O(∩_∩)O 期望理论，又称作“效价-手段-期望理论”，北美著名心理学家和行为科学家维克托·弗鲁姆于1964年提出来的激励理论。 Expectancy Theory, also known as "Valence - Instrumentality - Expectancy", was advanced by famous North American psychologist and ethologist Victor Vroom in 1964. 期望理论的基础是：人之所以能够从事某项工作并达成目标，取决于个人对于其执行任务和接受期望回报的能力的心理预期。 The premise of Expectancy Theory: Motivated by mental expectations about their ability to perform tasks and receive desired reward, men can fulfill certain tasks and achieve certain goals.
