A demo of the experiment can be viewed [here](http://simonslab.com/game/xtransit_demo.html). The procedure for this experiment is identical to that of [the previous experiment](https://osf.io/5p7da/) except for the behavior of the unexpected probes. In this experiment there are two probe conditions. As before, the probe spawns when the player has traveled 360 pixels, and it always spawns 122 pixels behind the player horizontally. It can spawn in one of two vertical locations; 122 pixels above the player, or 244 pixels above the player. The probe can spawn when the player is crossing left-to-right (crossing 7 of 10) or right-to-left (crossing 8 of 10); this is assigned randomly. After spawn, the probe moves diagonally, traveling at 4 pixels per second in the x-dimension and 2 pixels per second in the y-dimension. It travels 244 pixels horzontally and 122 pixels vertically total. If the probe spawns far above the player (244 pixels), it moves diagonally downward to overtake the player and finish close to them. If it spawns near to them (122 pixels above), it moves diagonally upward to finish farther away from the player. The two possible motion paths are reflections of each other, so distance to the player over the course of the trajectory is identical (assuming the player is moving the entire time the probe is onscreen, or that players do not have different movement patterns across the two conditions). This manipulation therefore controls for distance but allows us to test whether a probe that moves into a more relevant area (the area above and in front of a player) is noticed more often than one that moves into a less relevant area (farther above the player). We will recruit 250 subjects, anticipating a 20% exclusion rate, to finish with 100 per condition.