Human Tails: Ownership and Control of Extended Humanoid Avatars 


This paper explores body own­er­ship and con­trol of an “extend­ed” humanoid avatar that fea­tures a dis­tinct and flex­i­ble tail-like appendage pro­trud­ing from its coc­cyx. Thir­ty-two par­tic­i­pants took part in a between-groups study to pup­peteer the avatar in an immer­sive CAVETM-like sys­tem. Par­tic­i­pants’ body move­ment was tracked, and the avatar’s humanoid body syn­chro­nous­ly reflect­ed this motion. How­ev­er, six­teen par­tic­i­pants expe­ri­enced the avatar’s tail mov­ing around ran­dom­ly and asyn­chro­nous to their own move­ment, while the oth­er par­tic­i­pants expe­ri­enced a tail that they could, poten­tial­ly, con­trol accu­rate­ly and syn­chro­nous­ly through hip move­ment. Par­tic­i­pants in the syn­chro­nous con­di­tion expe­ri­enced a high­er degree of body own­er­ship and agency, sug­gest­ing that visuo­mo­tor syn­chrony enhanced the prob­a­bil­i­ty of own­er­ship over the avatar body despite of its extra-human form. Par­tic­i­pants expe­ri­enc­ing body own­er­ship were also more like­ly to be more anx­ious and attempt to avoid vir­tu­al threats to the tail and body. The high­er task per­for­mance of par­tic­i­pants in the syn­chro­nous con­di­tion indi­cates that peo­ple are able to quick­ly learn how to remap nor­mal degrees of bod­i­ly free­dom in order to con­trol vir­tu­al bod­ies that dif­fer from the humanoid form. We dis­cuss the impli­ca­tions and appli­ca­tions of extend­ed humanoid avatars as a method for explor­ing the plas­tic­i­ty of the brain’s rep­re­sen­ta­tion of the body and for ges­tur­al human-com­put­er interfaces.


This project was sup­port­ed by the FP7 EU col­lab­o­ra­tive project BEAMING (248620). Mel Slater was also sup­port­ed by the ERC Advanced Grant TRAVERSE.


  title={Human tails: ownership and control of extended humanoid avatars},
  author={Steptoe, William and Steed, Anthony and Slater, Mel},
  journal={Visualization and Computer Graphics, IEEE Transactions on},