Enhancing the contrast sensitivity function through action video game training

Abstract

The contrast sensitivity function (CSF) is routinely assessed in clinical evaluation of vision and is the primary limiting factor in how well one sees. CSF improvements are typically brought about by correction of the optics of the eye with eyeglasses, contact lenses or surgery. We found that the very act of action video game playing also enhanced contrast sensitivity, providing a complementary route to eyesight improvement.

Figure 1

Improved CSF as a result of action video game experience. (a) The CSF was assessed at five different spatial frequencies (1.5, 3, 6, 9 and 12 cycles per degree) by using a two-interval forced-choice procedure in which subjects had to decide which of two intervals, each marked by the presence of four peripheral cross-hairs, contained a Gabor patch. Unlike in the typical clinical procedure, the size of the Gabor patch was scaled with frequency so that the space constant of the Gabor was equal to one period of the grating at all frequencies. A trial consisted of a 30-ms Gabor signal and a 30-ms blank screen, separated by an 800-ms interval. Participants were asked to indicate which 30-ms interval marked by the cross-hairs contained the Gabor signal. Contrast of the Gabor was modulated in 0.1-log-unit steps following a 3-up–1-down staircase to find the 79% threshold. (b) Contrast sensitivity as a function of spatial frequency in VGPs (n = 10) versus NVGPs (n = 10) and in the action-trained (n = 6) and control-trained groups (n = 7) pre- and post-training. VGPs showed higher contrast sensitivity (plotted in log units) than NVGPs (group effect: F_1,18 = 9.37, P = 0.007, partial eta squared (η_p²) = 0.34). This group difference was greater at intermediate and higher spatial frequencies (F_4,72 = 2.48, P = 0.05, η_p² = 0.12). In the training experiment, the action-trained group showed a significant improvement in contrast sensitivity as a result of training, whereas no such change was noted in the control-trained group (pre/post × group interaction: F_1,11 = 5.65, P = 0.04, η_p² = 0.34). Curves were obtained by smoothed interpolation between data points. Error brackets are s.e.m. * P < 0.05, ** P < 0.01.

Figure 2

Improved critical duration as a result of action video game experience. (a) Contrast sensitivity (plotted in log units) at 6 cycles per degree as a function of display duration (10, 20, 30, 60, 120 and 180 ms) for VGPs (n = 7) versus NVGPs (n = 9), and the action-trained (n = 13) and control-trained groups (n = 9) pre- and post-training. Curves are maximum-likelihood fits of the exponential saturation function log(CS) = log(CS_max) − ae^−t/τ, where t is the time in milliseconds, CS_max is the asymptote, a is the amplitude and τ is the time constant. Exponential fits to the individual data were good (VGP, r² = 0.99; NVGP, r² = 0.98). (b) Critical duration was shorter in VGPs than NVGPs (group effect: F_1,14 = 6.60, P = 0.02, η_p² = 0.30); in the training study, the action-trained group showed reduced critical duration post-training, whereas the control-trained group did not (pre/post × group interaction: F_1,20 = 6.35, P = 0.02, η_p² = 0.24). Error brackets are s.e.m. * P < 0.05, ** P < 0.01.