||Individuals perceive their ability to act in the environment, termed affordances, by evaluating the relationship between their own capabilities and dimensions and the properties of the environmental objects and surfaces that surround them (Gibson, 1979/1986, Richardson, Marsh & Baron, 2007; Ishak, Adolph & Lin, 2008; Beauvois & Dubois, 2000; Chang, Wade & Stoffregen, 2009; Warren, 1984). J.J. Gibson (1979/1986) argued that affordances convey possible interactions between animals and their environments (Stoffregen, Gorday, Sheng & Flynn, 1999). Much research has argued that understanding one's body size is critical for perceiving action capabilities (Gibson; 1979/1986; Mark, 2007; Ishak, Adolph, & Lin, 2008; Witt, Sugovic, & Taylor, 2012; Ramenzoni, Davis, Riley, & Shockley, 2010; Stefanucci & Geuss, 2009; Oudejans, Michaels, Bakker & Dolne, 1996). Recent work also suggests that observers can perceive their own affordances, as well as affordances for another's actions (Stoffregen, Gorday, Sheng & Flynn 1999; Mark, 2007), and that at times a participant's own action capabilities hasve the potential of influencing judgments of another person's action capabilities (Ramenzoni, Davis, Riley, & Shockley, 2010; Ramenzoni, Riley, Davis, Shockley, & Armstrong, 2008). The current study asks whether another person is capable of influencing one's self-perception of aperture passage. The participants (N=23) completed 120 trials in virtual reality, in which they judged whether they or an avatar (in counter-balanced order) could pass through 12 aperture widths (ranging from 30-85cm in repeated measures (ANOVA), five different avatars were scaled to the participant's width and presented randomly throughout the experiment (i.e., 20 % smaller, 10% smaller, equal to participant, 10% larger, and 20% larger). Afterwards, the participants completed a matching task for which they estimated the widest part of each avatar. Since previous research has found that participants making self-judgments tend to be influenced by the presence of another person (Gagnon, Geuss, Stefanucci, & Creem-Regehr, 2013), we hypothesized that viewing virtual avatars of different sizes would influence self-judgments of aperture passage and that participants would accurately judge what the avatars could pass through. Overall, participants made accurate judgments about their own ability to pass through the aperture widths, regardless of the width of the avatar. The judgments made for the avatar's ability to pass through the apertures were accurate only when the avatar was the same size as the participant, while the judgments of aperture passage for larger and smaller avatars were incorrect. The matching task showed that participants did not accurately perceive differences in avatar widths, which may reaffirm the finding that participants judged avatar passage incorrectly. While the current findings about self-perception support previous research that has found that people accurately judge their own action capabilities, the results contradict research that has argued that observers are accurate at perceiving another person's action capabilities. The advantages and disadvantages, of the use of virtual reality as an effective method to test affordance perception, are discussed.