The likelihood with which language users insert optional words or morphemes that explicitly mark syntactic structure tends to increase in complex grammatical environments. This positive correlation between explicitness and complexity, best known as the Complexity Principle, has been observed for a multitude of case studies in both naturally occurring language and experimental settings. Researchers have sought the explanation for this Complexity Principle in three different domains: cognitive comprehension processing, the language channel, and cognitive production processing. Based on these accounts, we formulate predictions regarding the action radius of the Complexity Principle in the alternation between a direct and prepositional object of the Dutch verb zoeken ‘search’. These predictions are tested against corpus observations. Our results confirm accounts according to which optional elements indicate production difficulties, as well as those that explain the Principle as a result of restrictions on the language channel. In addition, our results indicate that the Principle is sensitive to context-determined restrictions that are the result of its underlying cause. This may present a possible caveat for alternation studies.