Dark-is-More Bias Also in Dark Mode? Perception of Colours in Choropleth Maps in Dark Mode

Dark mode is an increasingly common design option in which a dark screen background is used with light-coloured text and graphic elements. This option is, therefore, also relevant for the design of screen maps. This article examines the question of whether a “light-is-more bias” also applies in dark mode for the display of choropleth maps, analogous to the “dark-is-more bias” with light backgrounds (i.e. that dark colours are associated with greater attribute values). However, the results of an online study with 214 people show that the dark-is-more bias is still clearly the most frequently used strategy. This frequency is slightly lower compared to the light mode, and it is depending on the specific colour scheme for the dark mode and on user’s expertise. The study results also allow general design recommendations for dark-mode colour schemes for maps.