The objective of the Reversible Figures experiment was to investigate whether the perception of ambiguous figures is affected by microgravity. The hypothesis is that the number of perceived reversals of perspective-based reversible figures is altered in microgravity when compared to normal gravity, but that the perceived reversal of 2D figures is not affected. Ambiguous reversible figures are seen with a statistically known preference in 1g. This hypothesis is to be verified by determining for all phases of the space flight: (1) the time for first reversal and the number of perceived reversals of 3D and 2D reversible figures in a given time frame; and (2) the probability for seeing each view/reversal within a figure.
Subjects were first tested at approximately launch minus (L-) 220 days, L-160 days, and L-80 days. The in-flight sessions took place on flight days (FD) 5–14 (mean FD08), FD20-36 (mean FD26), FD63-102 (mean FD72), and FD106-174 (mean FD134). Finally, they were tested again one day after return to Earth (R+1 day) and at R+5 and R+9 days.
The time to first percept reversal and the number of reversals were not different in orbit and postflight compared to preflight results. While on the ground, when watching depth-ambiguous perspective figures, all subjects reported seeing one three-dimensional interpretation more often than the other. In microgravity this asymmetry gradually disappeared and after three months in orbit both interpretations were seen for the same duration. These results suggest that the perception of “illusory” depth is altered in astronauts during space flight. The increased depth ambiguity is attributed to the lack of the gravitational reference and the eye-ground elevation for interpreting perspective depth cues.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 32||07/01/2012||09/16/2012||78 days|
|Expedition 33||09/16/2012||11/18/2012||63 days|
|Expedition 34||11/18/2012||03/15/2013||117 days|
|Expedition 35||03/15/2013||05/13/2013||58 days|
|Expedition 36||05/13/2013||09/10/2013||166 days|
|Expedition 37||09/10/2013||11/10/2013||61 days|
|Expedition 38||11/10/2013||03/10/2014||120 days|
|Expedition 39||03/10/2014||05/13/2014||64 days|
|Expedition 40||05/13/2014||09/10/2014||133 days|