memory

You forget your intentions when you walk through doorways.

A 2011 study found that entering a new room significantly decreases your ability to recall information from the previous one.

This occurs because the brain treats doorways as event boundaries. It clears the current context to prepare for new environmental information.

You are losing your train of thought because your brain is trying to save storage space.

Where this comes from

Study: Gabriel Radvansky, 2011, Quarterly Journal of Experimental Psychology
What the check found: The study 'Walking through doorways causes forgetting: Further explorations' (Radvansky et al., 2011, QJEP) accurately describes the 'event horizon' or doorway effect.
Confidence: Well replicated

One of these every day, and every one names the study it came from. When a finding is contested, it says so.