Many psychological studies have shown that human‐generated sequences are hardly ever random in the strict mathematical sense. However, what remains an open question is the degree to which this (in)ability varies between people and is affected by contextual factors. Herein, we investigated this problem. In two studies, we used a modern, robust measure of randomness based on algorithmic information theory to assess human‐generated series. In Study 1 (), in a factorial design with task description as a between‐subjects variable, we tested (...) the effects of context and mental fatigue on human‐generated randomness. In Study 2 (), in online research, in experimental design, we further investigated the effect of mental fatigue on the randomness of human‐generated series and the relationship between the need for cognition (NFC) and the ability to produce random‐like series. Results of Study 1 show that the activation of the ability to produce random‐like series depends on the relevance of the contextual cues (), whether they activate known representations of a random series generator and consequently help to avoid the production of trivial sequences. Our findings from both studies on the effect of mental fatigue (Study 1 – ; Study 2 – ) and cognitive motivation () demonstrate that regardless of the context or task's novelty people quickly lose interest in the random series generation. Therefore, their performance decreases over time. However, people high in the NFC can maintain the cognitive motivation for a longer period and consequently on average generate more random series. In general, our results suggest that when contextual cues and intrinsic constraints are in optimal interaction people can temporarily escape the structured and trivial patterns and produce more random‐like sequences. (shrink)