The rubber hand illusion is experienced when a person is tricked into believing a fake hand is his or her own. In the task, an individual places his or her right hand into one side of a two-compartment box with an opaque cover. A life-like, rubber hand is placed in a neighboring compartment with a transparent cover. The illusion can be created when the individual’s index finger and the index finger of the rubber hand are stroked at the same time with a paintbrush (for 3+ minutes).
The visual and tactile cues of seeing and “feeling” the stroking of the paintbrush on the rubber hand override proprioceptive input (feeling the locations of body parts in space). Many individuals report that they feel like their real hand seems to drift toward the rubber hand while experiencing the illusion. Some people also feel like their real hand is turning rubbery or believe they can actually feel the stroking of the paintbrush on the rubber hand. Weird, right?
I was fascinated by a research study examining the responses of patients with schizophrenia to the rubber hand illusion and wanted to see how women with eating disorders would respond to the illusion. Previous research has also suggested that women with anorexia nervosa may be more susceptible to the illusion than healthy women. I wondered why that might be, and wanted to find out more. It could possibly be because women with anorexia nervosa are less attuned to their own bodies, are highly affected by environmental cues regarding body image, and have abnormal processing of spatial and visual information about their own bodies. To understand this more thoroughly, I designed my honors thesis project to look at susceptibility to the rubber hand illusion in women with and without anorexia nervosa. It’s been an awesome project so far, and I’ll let you know how it turns out!
Katie Weinel is senior undergraduate Psychology and Biology major and has worked as a trainee with the UNC Center of Excellence for Eating Disorders for the past four (going on five!) semesters. Her thesis is being supervised by Stephanie Zerwas, Ph.D., Associate Director of Research.
Want to see the rubber hand illusion in action? Check out these videos:
By: Katie Weinel