Chunking on the fly in working memory can be observed while measuring the compressibility of information likely to allow the formation of chunks. A novel metric of algorithmic complexity for short strings was used to measure the compressibility of each sequence of stimuli in an immediate-serial-recall task resembling the Simon electronic game. In this new task, working memory capacity allowed the span to vary depending on the sum of compressible information. This particular paradigm was thought to examine the processing and storage components together in association. The hypothesis was that the processing component plays a more major role when dedicated to the to-be-remembered items, instead of when it is directed away to a concurrent task. The report of two experiments (N = 293) shows the relationship of the Simon span task to both simple and complex span tasks, and we show that this new task is likely to better predict intelligence.