Researchers found that imagining walking through a doorway can also interfere with your memory. Worse still, phrases that insert a temporal boundary between events have the same sort of mental divider as a doorway. For example, reading a sentence that starts with "A few hours later..."

This tells us that our brains operate with certain mechanical dynamics. When you can't remember why you walked through a doorway, don't be alarmed. Your brain simply thought the doorway meant you needed a memory divider.