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Stimulus Onset Asynchrony (SOA)

Article by Ben Howell

Figure 1. Stimulus Onset Asynchrony

Figure 1. Stimulus Onset Asynchrony

In experimental psychology, Stimulus Onset Asynchrony is defined as the duration of time between the onset of one stimulus and the onset of another stimulus. In (Figure 1) the duration between the onset of the stimulus S1 and the onset of the stimulus S2 is the Stimulus Onset Asynchrony (SOA) interval. Stimulus Onset Asynchrony manipulation is sometimes used as an experimental factor in temporal order judgement experiments.


Stimumuls Onset Asynchrony in Psychstudio

In the example shown in (Figure 2) we have a trials timeline containing a Stimulus Onset Asynchrony of 40ms as the difference between the start time of S1 (40ms) and the start time of S2 (80ms) is 40ms. Setting stimulus start time and duration is done in the trials timeline editor as shown in (Figure 3)

Figure 2. Asynchronous stimulus onset (Psychstudio trials timeline)

Figure 2. Asynchronous stimulus onset (Psychstudio trials timeline)

Figure 3. Editor (Psychstudio trials timeline)

Figure 3. Editor (Psychstudio trials timeline)

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Ben Howell
Ben Howell
Founder, Psychstudio