In the present study, we examined the rate of change among college students’ (N = 429) competence beliefs, interest value, importance value, and four facets of cost measured weekly across a semester of two introductory calculus courses. We also examined how baseline levels of expectancy-value motivational beliefs predicted initial levels and rates of change in weekly expectancy-value beliefs. Results suggested that competence-related beliefs, interest value, and importance value decreased weekly throughout the semester, whereas outside effort and loss of valued alternatives cost increased. Additionally, baseline levels of each task-value-related construct predicted initial weekly levels of their respective constructs, but did not generally predict changes in task values over time. Conversely, baseline competence-related beliefs predicted slower declines in weekly competence-related beliefs, as well as slower declines in importance value and slower increases in outside effort cost, loss of valued alternatives cost, and emotional cost. Finally, baseline importance value predicted larger increases in weekly cost beliefs for all four dimensions of cost that were examined. Together, findings point to the importance of providing early course supports to buffer students against motivational challenges that threaten course participation and performance. Findings also suggest that students’ initial levels of competence-related beliefs are an important buffer against introductory course motivation declining across a semester, whereas initial importance value may have both positive and negative motivational consequences.

在本研究中，我们检查了大学生 ( N  = 429) 能力信念、兴趣值、重要性值以及每周在两门微积分入门课程的一个学期中测量的四个方面的成本的变化率。我们还研究了期望值动机信念的基线水平如何预测每周期望值信念的初始水平和变化率。结果表明，在整个学期中，与能力相关的信念、兴趣值和重要性值每周都在下降，而外部努力和失去有价值的替代方案的成本却在增加。此外，每个任务价值相关构造的基线水平预测了其各自构造的初始每周水平，但通常不预测任务价值随时间的变化。相反，基线能力相关信念预测每周能力相关信念下降较慢，重要性值下降较慢，外部努力成本、有价值替代成本损失和情感成本增长较慢。最后，基线重要性值预测所检查的所有四个成本维度的每周成本信念会出现更大的增长。总之，研究结果表明了提供早期课程支持的重要性，以缓冲学生免受威胁课程参与和表现的动机挑战。研究结果还表明，学生与能力相关的信念的初始水平是防止入门课程动机在整个学期下降的重要缓冲，而初始重要性值可能会产生积极和消极的动机后果。