3D stereoscopic displays have become popular in our life. Some studies show that this new technology affects our ability to recognize objects. However, it is not well known how our brain is modulated by the technology. In the current study, eighteen healthy adults participated. They were asked to make blocks same as pictures shown on a monitor. The task was similar to an intelligence test. There were two sets of pictures, 2D and 3D. The stimuli were presented through the Nvidia 3D vision system. During the task, activation in parietal area, which is related to spatial cognition, were recorded by a functional near-infrared spectroscopy (NIRS). Compared to 3D pictures, 2D pictures more activated parietal area. The result indicated that the task with 2D pictures required more spatial cognition to compute depth information of the blocks from 2D pictures, which leads to activation of parietal area.