This preregistration describes a within-subjects experiment investigating whether and how cultural priming would influence emotional valence ratings among unbalanced Mandarin–English bilinguals immersed in an L2 environment. Participants rate positive, negative, and neutral words in three cultural contexts (no context, native culture, second culture). We hypothesise that activating either native or second culture will enhance the extremity of valence ratings, compared to the no context baseline, with stronger effects when the native (Chinese) culture is primed. Trial-level valence ratings will be analysed using a linear mixed-effects model with fixed effects of Culture, Valence, and their interaction.