This dataset includes data on behavioural outcomes for the audio-visual simultaneity judgement task and emotion recognition task used in the publication, "An RCT study showing few weeks of music lessons enhance audio-visual temporal processing". In this study, the authors investigated the effect of eleven weeks of piano lessons on audio-visual temporal processing and emotion recognition abilities in adults. The data is organised to facilitate replication of the analyses carried out in this study, which includes the raw data of the two tasks mentioned above collected from each participant over seven data-collection sessions.  A 'Read-me-first' file is included in both data folders that introduce the structure of the data, the meaning of the file names, and how to interpret the raw data.