Informal workplace learning (IWL) is the predominant form of vocational learning. In striving to foster IWL, the focus of previous research has been on work design: according to the active learning hypothesis, both job resources and job demands can lead to learning. Informal learning research has so far agreed with this assumption but has hardly investigated the direction of effects or explaining mechanisms. The alternative active shaper hypothesis suggests that engagement in learning leads to more job resources but can also create higher job demands. The underlying processes in both hypotheses may be related to proactive behavior such as job crafting. In this article we present the results of two longitudinal studies focusing on job control and workload. In study 1, we used a cross-lagged panel design with structural equation modeling to analyze two-wave data with a 1.5-year interval among 129 blue-collar workers. The results suggest that IWL leads to job control and workload; the reverse causal direction was not significant. Hence, study 1 provided support for the active shaper hypothesis. In study 2, we used three-wave data with a 4-week interval among 216 white-collar workers to examine potential mediating effects of job crafting in the relationship between IWL and work characteristics. The results supported the assumption that task crafting and relational crafting mediate between job control and IWL and vice versa, and that relational crafting mediates between IWL and job control. No mediating effects were found with respect to workload, and cognitive crafting did not function as a mediator either. In supplemental analyses, we found mostly evidence that informal learning and job crafting are distinct constructs. The findings partly contradict the predominant active learning hypothesis and have implications for workplace learning research and personnel development in organizations.

非正式工作场所学习（IWL）是职业学习的主要形式。在努力促进IWL的过程中，以往的研究重点都集中在工作设计上：根据主动学习假说，工作资源和工作需求都可以导致学习。迄今为止，非正式学习研究已经同意这一假设，但几乎没有研究影响的方向或解释机制。另类主动塑造假说表明参与学习可以带来更多的工作资源，但也可以创造更高的工作要求。两种假设中的基本过程可能与主动行为（例如工作重塑）有关。在本文中，我们介绍了两项针对工作控制和工作量的纵向研究的结果。在研究 1 中，我们使用交叉滞后面板设计和结构方程模型来分析 129 名蓝领工人中间隔 1.5 年的两波数据。结果表明，IWL 会导致工作控制和工作量；反向因果方向并不显着。因此，研究 1 为主动塑造假说提供了支持。在研究2中，我们使用了216名白领工人中间隔4周的三波数据来检验工作重塑在IWL和工作特征之间关系中的潜在中介作用。结果支持这样的假设：任务设计和关系设计在工作控制和 IWL 之间发挥中介作用，反之亦然，而关系设计在 IWL 和工作控制之间起到中介作用。没有发现工作量的中介效应，认知能力也没有发挥中介作用。在补充分析中，我们发现大部分证据表明非正式学习和工作塑造是不同的结构。研究结果在一定程度上与主要的主动学习假设相矛盾，并对工作场所学习研究和组织中的人员发展具有影响。