Before 2010, each VIS conference typically featured 0-2 papers on empirical studies. The VisWeek 2010 in Salt Lake City became a turning point, and since then more and more empirical study papers have been presented at VIS. Between 2016 and 2019, there were some 60 empirical study papers in VIS/TVCG tracks. Many young talents who are knowledgeable in both VIS and psychology emerged in the VIS community, while many colleagues in psychology are authoring and co-authoring such papers and attending VIS conferences. It is therefore timely to ask: Is there a need for “Visualization Psychology” as a new interdisciplinary subject? Led by young researchers in both VIS and psychology, this proposed workshop will complement BELIV and VISxVISION by (i) identifying a broad range of visualization phenomena that cannot be adequately explained by existing theories and experiments in VIS and psychology; (ii) Exploring the research questions beyond the scope of visual perception and reaching out to more research findings in psychology in many areas of cognition; and (iii) Enabling visualization and visual analytics to become a rich playground for making fundamental discoveries in psychology and cognitive science in general.