In House of Leaves, it is suggested that the maze of hallways and rooms was created by the psychological agonies of the houses inhabitants over the years. If this is the case, it is easy to see why the space reacts to the people exploring it.
The first case of this is during Exploration A. On this journey down the hallway, Navidson primary objective is to just take a “little look around.” Before the journey, we have seen the hallway go anywhere from 100 feet deep to 10 feet deep. However, this time when Navidson comes to what was the end of the hallway, he finds a new door. The door has only appeared there as a response to Navidson’s desire to explore the phenomenon that is the hallway.
The space continues to adapt as Navidson explores further, creating more hallways and bigger rooms. As Navidson explored more and more, the space increasingly changes to give him additional territory to cover. However, Navidson’s curiosity is what brings about his panic on page 67. By that point the space has provided Navidson with so much to explore that he is lost. Once Navidson realizes this, he changes from an exploratory mindset to a panicked mindset. The space adapts to Navidson and instead of giving him new places to explore, starts rearranging the rooms and hallways much like the way his thoughts are now scattered. Additionally, the more Navidson panics, the more the space shifts.
The next major case we see of this is during Exploration 4. The major difference in this Exploration, besides the supplies being taken along, is that Holloway takes his rifle. While most of the Exploration goes as planned, on the way back up Holloway begins to be depressed over the fact that they have found nothing new. With his change from focusing on exploring to constantly thinking about finding Something, the space creates a Something for Holloway to chase after. Holloway needs this Something to set himself apart from the rest of the world.
An even more extreme example of how the space reacts to what the explorers want is when Navidson descends the Grand Staircase in his search for the Holloway, Jed, and Wax. When Holloway and his team had tried descending the staircase on previous expeditions, they were exploring the space. Because they were exploring, the space continuously provided the team with more ground to cover. However, when Navidson descends the staircase, his goal is to find the missing team. Since his goal is not exploration, the space reacts to Navidson by shortening the staircase a considerable amount. When Navidson changes his goal from exploration to search and rescue, the space responds by leading him to Jed and Wex.
As long as an explorer is able to wrap his head around the general principle that governs the space, he should be able to create anything he wants simply by wanting it. That is because the space is whatever you want it to be. As long as you enter the hallway searching for Something, the space will make that Something real for you.