PsySuite, an Android App for behavioural tests in the temporal domain

We present PsySuite, an Android App designed to perform multimodal behavioral tests in the temporal domain. This class of tests consists in delivering either unimodal or multimodal visual, acoustic and tactile stimuli and asking participants to evaluate their temporal features: duration, temporal distance between stimuli and simultaneity across different modalities. The accuracy and reproducibility of our stimuli production mechanism was evaluated with an oscilloscope on two different smartphones models. Then, we validated the App running two versions of the double-flash illusion (DFI) test in seven healthy adults. DFI was selected as it induces a perceptual illusion only when stimuli are precisely delivered within few milliseconds. We found the App could reliably produce stimuli with a minimum duration of 7 ms, 17 ms and 35 ms respectively for acoustic, visual and tactile stimuli. Oboe library outclassed AudioTrack solution in playing pairs of sounds, whilst visual and tactile performance was highly dependent on the smartphone’s model used. In the DFI test using "long" stimuli (35 ms) we did not find the flash illusion effect. We could run the "short" (audio: 7 ms, visual: 17 ms) stimuli version only with audio-visual stimuli and we found a strong effect consistent with the literature using classical experimental, PC-based, setups. These results suggest that our PsySuite App can be used to run highly demanding audio-visual psychophysics experiments obtaining the same effect found with classical setups.