This dataset was collected in a public event for children in 2017. Children between ages 3-9 years were invited to take part in the study. Both tasks were presented on a tablet PC (Samsung 10.1 tablet SM P600) running the START app. Details of the app and the START project are available at the https://startproject.bhismalab.org. Related publication: Dubey, I., Brett, S., Ruta, L., Bishain, R., Sharat Chandran, Bhavnani, S., Belmonte, M.K., Lockwood Estrin, G., Johnson, M., Gliga, T., and Chakrabarti, B., on behalf of the START consortium. (2022), Quantifying preference for social stimuli in young children using two tasks on a mobile platform. PLOS One, Accepted.