Decoding time from space: A review of the complication clock and its representation of temporal experience.

The complication clock, originally introduced by Wilhelm Wundt, remains a pivotal method in experimental psychology for probing the subjective timing of events. By localising the position of a moving pointer, one can objectively measure when someone perceives an event to have occurred. The method therefore maps temporal judgments via a spatial representation of time on the basis of a moving pointer. Although it provides a unique tool for capturing otherwise unobservable phenomena, the method also raises critical conceptual and methodological challenges. In this article, we provide a historical account of the research, from early complication experiments on sensory processing through Libet's (Libet et al., 1982) repurposing for volition research to present-day investigations of sense of agency, affect, and perceptual awareness. We then discuss the measurement structure of the clock, illustrating how the spatial nature of the clock introduces systematic distortions to time reports and examining conditions under which these distortions can be identified and controlled. We further show that the method carries an implicit commitment to serial-discrete temporal order, constraining the range of cognitive phenomena that the clock is able to investigate. These analyses can help to inspire greater methodological and conceptual sensitivity for future investigations into our subjective timing of events.