Experimental design
APPENDIX
We conducted a field experiment during the 2020 U.S. Democratic presidential primary election on a text-based social media platform designed for academic research,(see Fig. 
Research design. In the control condition, one man talks to one woman, and both discussants are represented by an avatar associated with their self-reported gender. The treatment conditions also pair one man and one woman, but the treated discussion partner views an avatar that does not match the self-identified gender of their mislabeled discussion partner. The same-gender conditions pair men to converse with another man and women to converse with another woman, and both discussants are represented by an avatar associated with their self-reported gender. Note that contrasting the same-gender and any cross-gender conversations does not identify the causal effect of gender because only partners were randomized, not partner gender (holding other partner characteristics fixed). Men and women differ on many unobserved characteristics, so changing someone’s discussion partner from a man to a woman changes more than just the partner’s gender. See Supplementary Appendix Sect. In the conversation, gender presentation is manipulated through random assignment of a male or female avatar for some respondents. The text-based conversation means that gendered patterns develop through an ongoing social interaction, but that gender can only be communicated through the display avatar and the text of messages sent, with no interference from physical, visual, or vocal cues.Participants were randomly assigned to one treatment or control conversation, and the experimental effects are estimated by comparing the between-subjects differences in averages using 