Grant: Discovery Grants Program - Individual

In this grant period, my goal is to pursue a program of study aimed at clarifying the principles that control human time perception. This goal is part of a larger, longer-term goal to illuminate the processes that underlie how people construct the various aspects of their reality by imposing structure on their apprehension of sensory inputs. My prior research provided an investigation of sources of error in the perception of the spatial location, and the duration and intensity of auditory and visual events. For example, Alards-Tomalin, Leboe-McGowan, Shaw, & Leboe-McGowan (2014) demonstrated that similarity in number magnitude, size, and colour saturation biases the perception of time, such that intervals that are flanked by markers that are similar in magnitude on these dimensions are perceived as shorter in duration than intervals that are flanked by markers that are quite different in magnitude. That is, the similarity of the interval markers influenced the perception of time, independent of the actual duration. We have interpreted these results through an application of Walsh's (2003) A Theory of Magnitude (ATOM). According to this approach, magnitude similarity distorts perceived duration because the processing of magnitude for a variety of dimensions occurs within a general-purpose magnitude processing system in the intraparietal sulcus region of the brain. However, there are some problems with this interpretation, and I have identified some of these in my previous research (Alards-Tomalin, Walker, Kravetz, & Leboe-McGowan, 2016; Alards-Tomalin, Walker, Nepon, & Leboe-McGowan, 2017). As an alternative to an ATOM approach, I propose a program of research to investigate how heuristic inferences, guided by similarity-based grouping processes, help to guide our mental construction of the passage of time. Specifically, I propose to test the contribution of such grouping processes by creating interval markers that combine different bases of similarity. These will include similarity based on physical (overlapping stimulus features) and meaning-based stimulus features (semantic relatedness), as well as stimulus-independent features generated by task demands (i.e., performing the same task in response to the same or different stimuli). Of particular theoretical relevance are dimensions of similarity that are not magnitude dependent. An ATOM approach cannot explain such influences of similarity on judgments of event duration. That approach can only explain distortions of time perception caused by perception of other magnitude dimensions, such as size and intensity. Consequently, my research aims to resolve the important theoretical question of whether irrelevant features of events bias the perception of time through an ATOM-based process of interfering magnitude dimensions or a broader influence of heuristics (i.e., simple decision rules) that we use to infer and construct the nature of our moment-to-moment experiences with the external world.