Quadro k600

All stimuli were displayed on a Sony MultiScan G520 monitor driven by an NVIDIA Quadro K600 video card and generated by a PC computer running Matlab (The Mathworks Corp., Natick, MA) with PsychToolBox 3 extensions^{85 (link), 86 (link)}. The monitor had a total display area of 40.0 cm × 30.0 cm, with a resolution of 1920 × 1440 pixels (1600 × 1200 pixels for 8 additional anisometropic amblyopes) and a refresh rate of 85 Hz. Participants with their best refractive corrections viewed the stimuli monocularly, which were presented on the centre of the monitor. The untested eye was occluded with an opaque eye patch (see Fig. 1a). A chin-rest equipped with a forehead strap was used to minimize subjects’ head movements during the experiment. Participants were seated in a darkened room in which all local cues to vertical/horizontal were removed by using black cardboard in front of the monitor to provide a circular window of 30.0 cm in diameter to the display⁵¹ . The original 8 bits per pixel luminance range digitization was extended above 10 bits with the contrast box switcher^{87 (link)}, providing the necessary minimum contrast steps for contrast detection measures, and the monitor weekly calibrated with a custom laboratory automated procedure.

In each experiment, a mantis was hung upside down from a Perspex base and viewed full-screen stimuli on a CRT monitor (HP P1130). The base was held in place by a clamp such that the mantis was facing the middle point of the screen and the viewing distance (distance between mantis and monitor) was 7 cm in all trials. A web camera (Kinobo USB B3 HD Webcam) was placed under the base, providing a view of the mantis (but not the screen). The monitor, Perspex base and camera were all placed inside a wooden enclosure to isolate the mantis from distractions and to maintain consistent dark ambient lighting during experiments. The screen had physical dimensions of $40.4\times 30.2$ cm and pixel dimensions of $1600\times 1200$ pixels. At the viewing distance of the mantis, the horizontal extent of the monitor subtended a visual angle of 142 ${}^{\circ }$ . The mean luminance of the monitor was 27.1 cd/m ${}^2$ , and its refresh rate was 85 Hz.
Experiments were programmed in Matlab 2012b (Mathworks, Inc., Natick, MA, USA) and stimuli developed using Psychophysics Toolbox Version 3 (PTB-3) [37 (link),38 (link),39 ] were used. The experiment computer was a Dell Optiplex 9010 (Dell Corporation Limited, Bracknell, UK) with an Nvidia Quadro K600 graphics card running Microsoft Windows 7.

Adult participants were tested in a dark room at Newcastle University and children performed the experiment on the same equipment in a dimmed area at the Newcastle Centre for Life, a public science center. The stimuli were presented on a 47-inch LG 3D monitor (47LD920; LG, Yeouido-dong, Seoul, South Korea) with a screen size of 104 cm × 58.5 cm. This is a patterned-retarder passive 3D monitor, where circular polarization is used to separate the left and right images. The spatial resolution of the monitor was 1920 × 1080 pixels and the refresh rate was 60 Hz. Observers sat at a viewing distance of 200 cm so a pixel subtended 54.65 seconds of arc (arcsec) on average. Adult participants used a forehead and chin rest. Children did not use a headrest, but head position was closely monitored by the experimenter. Observers wore appropriate passive 3D glasses (Sky 3D glasses, Middlesex, UK). Participants recorded their responses by pressing the left or right button of a standard computer mouse. The experiments were conducted using a DELL workstation (DELL, Round Rock, TX, USA), with a NVIDIA Quadro K600 graphics card (NVIDIA, Santa Clara, CA, USA), running Matlab (R2012b; MathWorks, Natick, MA, USA). The experiments were programmed using Psychophysics Toolbox extensions^{15 (link)–17 (link, no link found)} (in the public domain, www.psychtoolbox.org).