“…During the past few decades, facial expression recognition (FER) has attracted increasing attention in computer vision due to its variety of applications in entertainment, sociable robotics, data-driven animation, and so on (Zhang et al, 2018a,b). Recently, with the considerable development of deep learning, FER has made substantial progress (Chang et al, 2019;Chen et al, 2020;Dapogny et al, 2018;Kollias et al, 2020a;Li and Deng, 2019;Li et al, 2017;Meng et al, 2017;Yan et al, 2020;Yang et al, 2018a;Zhang et al, 2018c).…”