Time Perception and Autistic Spectrum Condition: A Systematic Review
Objectives: A systematic review was conducted in an attempt to summarise the extant literature. This review considered a wider range of timing behaviours than previous reviews (e.g. Allman and Falter, 2015; Stevenson, et al. 2015). We also incorporated more information from the theories and cognitive models of timing developed in neurotypicals (NTs).
Methods: In March 2017, five databases were consulted. From an initial 597 records, 45 were selected and reviewed. These studies were organised according to different timing abilities tested: time sensitivity (the ability to discriminate stimuli based on temporal characteristics), perception of duration and higher-order time perception (referring to the capacity to think about time as a concept, where events take place within it, and the ability to be aware of one place in time and plan for events in the future).
Results: There was a tendency for studies in timing sensitivity to display differences in children, whereas adult performance was comparable to NTs. This may suggest at a developmental delay in time sensitivity in ASC. However, in many studies it is not possible to determine whether differences are the result of a true timing deficit, or instead reflect differences in decision criterion or in the attention to socially relevant stimuli. Perception of duration studies have also generated mixed findings, but studies which investigated memory effects on timing performance have highlighted divergent performance from NTs. To date, the few studies that have investigated higher order timing in ASC (e.g. concepts of time) have consistently observed differences from NT performance.
Conclusions: It remains unclear whether there is a timing deficit in ASC. Divergent performance on timing tasks could reflect differences in cognitive mechanisms unrelated to timing in ASC. Additionally, studies have tended to involve varied methods and sample characteristics which likely contribute to the heterogeneity of findings. A proposed schedule of work to address these issues will be presented.