Alpha-band frequency and temporal windows in perception: A review and meta-analysis of 25 experiments

Temporal windows in perception refer to windows of time within which distinct stimuli interact to influence perception. A simple example is two brief stimuli fusing into a single percept when they occur within a certain time range. It has long been hypothesized that the human alpha rhythm (an 8-13 Hz neural oscillation maximal over posterior cortex) is linked to temporal windows, with higher frequencies corresponding to shorter windows and finer-grained temporal resolution. Recently, this hypothesis has garnered support from studies demonstrating a correlation between individual differences in alpha frequency (IAF) and behavioral measures of temporal processing. However, non-significant effects have also been reported. Here, we review and meta-analyze 25 experiments correlating IAF with measures of temporal processing in visual and audio-visual perception. Our results estimate the true correlation in the population to be between 0.39 to 0.52, a medium-to-large effect. The effect held when considering visual or audio-visual experiments separately and when examining different IAF estimation protocols (i.e., eyes-open and eyes-closed). Moreover, using analysis choices that favor a null result, we still find a significant population effect. Our review shows that 1) effects have been internally and independently replicated 2) several positive effects are based on larger sample sizes than the null effects and 3) many reported null effects are actually in the direction predicted by the hypothesis. We discuss possible factors underlying the reported null effects as well as design recommendations and open questions for future researchers investigating the link between alpha frequency and temporal windows in perception. ### Competing Interest Statement The authors have declared no competing interest.