In fast-paced, dynamic tasks, the ability to anticipate the future outcome of a sequence of events is crucial to quickly selecting an appropriate course of action among multiple alternative options. There are two classes of theories that describe how
anticipation occurs. Serial theories assume options are generated and evaluated one at a time, in order of quality, whereas
parallel theories assume simultaneous generation and evaluation. The present research examined the option evaluation
process during a task designed to be analogous to prior anticipation tasks, but within the domain of narrative text comprehension. Prior research has relied on indirect, of-line measurement of the option evaluation process during anticipation
tasks. Because the movement of the hand can provide a window into underlying cognitive processes, online metrics such
as continuous mouse tracking provide more fne-grained measurements of cognitive processing as it occurs in real time.
In this study, participants listened to three-sentence stories and predicted the protagonists’ fnal action by moving a mouse
toward one of three possible options. Each story was presented with either one (control condition) or two (distractor condition) plausible ending options. Results seem most consistent with a parallel option evaluation process because initial mouse
trajectories deviated further from the best option in the distractor condition compared to the control condition. It is difcult
to completely rule out all possible serial processing accounts, although the results do place constraints on the time frame in
which a serial processing explanation must operate.

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• Mouse‑tracking evidence for parallel anticipatory option evaluation