Paper Reading #1: Imaginary Interfaces: Spatial Interaction with Empty Hands and without Visual Feedback

References:  Imaginary Interfaces: Spatial Interaction with Empty Hands and without Visual Feedback by Sean Gustafson, Daniel Bierwirth and Patrick Baudisch
Author Bios:
Sean Gustafson is currently a PhD student at the Human-Computer Interaction Lab of the Hasso Plattner Institute in Potsdam, Germany.  He holds both a Bachelor and Master's degree in Computer Science from the University of Manitoba in Canada.  Daniel Bierwirth currently resides in Berlin, Germany and is the cofounder of Matt Hattling & Company UG and the Agentur Richard GbR. H.  He received his undergraduate degree in Computer Science and Media from Bauhaus University and his Master's degree in IT-Systems Engineering from the Hasoo-Plattner Institute in Germany  Patrick Baudisch is a professor in Computer Science at Hasso Plattner Institute in Patsdam and the chair of the HCI Lab.    He earned a PhD in Computer Science from Darmstadt University of Technology in Germany.
Summary:
Hypothesis
The authors had three separate hypothesis corresponding to their experiments, but the overarching idea was that effective spatial interaction could occur without the need for a screen or other obvious visual feedback.
The specific hypothesis for the first experiment was that participants would perform fewer Graffiti recognition errors than previously reported by Ni and Baudisch.  They expected participants to build up visuospatial memory by watching their hands and completing the shapes.  The hypothesis for the second experiment had two parts.  First, that participants would be able to fully use their visuospatial memory while in a fixed position, but that body rotation would impair that ability.  Second, that in the rotate conditions, there should be lower error in the hand condition than in the none condition.  And finally, the hypotheses for the third experiment were that pointing accuracy would be highest at the fingertips and that pointing accuracy would decrease as the distance from the nearest fingertip increases.
Methods
For the first study, participants were asked to position their left hand like an "L" to mimic a coordinate origin and to reproduce a series of sketches with their right hand.  For the second study, the participants drew a picture and then pointed out one of the vertices that they had drawn.  And for the last experiment, participants were given target points in (thumb, index) length units and told to locate the position in their coordinate system.
Results

For the first experiment, 94.5% of the gestures were successfully recognized from the participant's drawings in the graffiti task, the average error for the repeated drawing task was about 2.2cm for the diamond and 3.25cm for the triangle, and the multi-stroke drawing task showed reasonable consistency in scale but less with stroke alignment and whitespace.
Contents
Between the three noted case studies, the goal was roughly the same.  Each study attempted to measure the participants' ability to map and measure drawing in free space, as well as testing their ability to associate the spatial mapping and detail related to location. 

Discussion:
I believe that the authors did achieve the goals that they set forth as far as determining that humans have some capacity for imaginary spatial imaging.  I was not completely convinced that this approach would ever prove to be a preferable solution, or even particularly applicable, however.  It is true that this paper is designed primarily to be a study of human ability rather than to actively put forth any particular ideas for development, and I think that it covered this very successfully.  However, I feel that the paper itself is interesting and significant only as an exercise in creative thinking.  It brings up some intriguing possibilities as far as how we might interface and interact with our technology in the future.