Imagine this: You are sitting comfortably on your couch, reading a book. Your mother asks you to get her bag from another room. As you get up, you see a notification on your phone and open it. When you’re done reading, you look up. You find yourself standing in another room but you can’t seem to remember why you went there.
There are times when you completely forget what it is that you had left a room for and have to move back to the room to recall that particular thought.
If you’ve experienced this circumstantial amnesia, then you are not alone. This happens to everyone, regardless of their mental ability.
Testing this effect
Some researchers from the University of Notre Dame looked into this. They set participants to perform memory tasks while crossing virtual doorways. In the experiment, participants were asked to select one object on their computer screen which would then be hidden in a virtual backpack. Then, they either moved across a room or through a virtual doorway into another room. Finally, participants answered a quiz asking them which object was currently in their backpack. Results showed that people who moved through a doorway had a harder time responding to the quiz than those who traversed the same distance within the room without passing through any doorways.
The same study was conducted in a real-life lab where participants had to carry an object inside a box. The results turned out to be similar to those of the virtual experiment.
Forgetting things when we pass through doorways is so common it’s been termed “the doorway effect”. But why does it even occur? To answer that, however, we have to understand how our minds receive and process information to turn it into memories.
What is memory?
Our brain is one of the most complicated and mysterious parts of our body. Despite decades of study, there is a wide range of phenomena related to the human brain that still cannot be explained. Memory, in particular, has been in the spotlight of medical science and psychology for a very long time.
Psychologist Robert Sternberg defines memory as “the means by which we draw on our past experiences in order to use this information in the present”. Think about it: how do you know that a fire will burn you, or that you’re allergic to a certain ingredient? Our “knowing” is based on the precedents cemented by our experiences, which (you guessed) are coded as memories.
Therefore, everything you know, you know because you remember.
How are memories formed?
The memory process can be divided into three steps: encoding, storage, and retrieval.
1. MEMORY ENCODING
When we receive information from our surroundings, it’s thanks to our sensory receptors. The sensory signal, however, has to be transformed before being stored in the central machinery of our minds. In other words, your sensory receptors speak in gibberish that the brain needs to decipher before recording it.
The process of translating this information into something useful for your consciousness is what we know as ‘perception’. The brain picks apart the sensory signals, remixes them and categorises the different stimuli, giving more attention to some details more relevant than others. This is why you might remember what your best friend ate before they puked that one time in school, but not necessarily who was sitting across the table or what they were wearing.
2. MEMORY STORAGE
Cool, you have translated the sensory input. Now, what?
According to the multistore model of memory, human memory goes through three record-keeping departments: the sensory register, the short-term memory (STM), and the long-term memory (LTM). This process is similar to storing things in your backpack; the deeper it is, the more secure it should be— but it’ll also be harder to retrieve later.
- SENSORY REGISTER
Our sensory organs first detect the information and bring it here, where it stays for only a few seconds. Sensory memory is like a holding container in which we dump everything our senses grab. Then, we can survey them and decide which bits are worthy of our attention. The unimportant stuff is promptly erased, whereas the relevant information moves to the short-term memory.
- SHORT-TERM MEMORY (STM)
The information that we care about enters the STM. Here, we can control the relevant bits and manipulate them. For example, our ability to do arithmetics relies on retaining numbers while we count. Cooking, crafting, shopping—these are all tasks that depend on our capacity to hold information for a short span of time.
- LONG-TERM MEMORY (LTM)
No memory is truly permanent until it reaches the LTM. Once the brain decides to store a memory for the long run, it encodes it in a series of connections between neurons. Should this network be activated by a trigger (like a similar event or a question about it), the memory will surface to consciousness.
3. MEMORY RETRIEVAL
Recovering information stored in our memory can be tricky. The things encoded in the LTM aren’t readily available; although all information is stored permanently in the brain, the connections that hold them work like muscles. If you don’t stimulate them regularly, they will become weaker to concede space and resources to other more important memories. However, some techniques make it easier to encode and (eventually) recall information.
The Doorway Effect
Which brings us back to doorways.
Psychologists believe that passing through a door creates a mental block or a divide in our memory. This is because our memory operates in an episodic manner: a sequence of events happens and we encode it as a single happening. Once an event boundary (a fancy term for an imaginary separator) is detected, the brain moves on to encode the next segment.
Moving from one location to another, for instance, is an event boundary. Information associated with one location becomes less available when we enter a new one. Therefore, when we pass from one room to another, our brain recognises that we’re entering a new space and adjusts accordingly.
The more scientific term for this is the “location-updating effect” (boring, we know). The doorway acts as a reset button in our memory, signalling the brain that it’s time to allocate attention to the new environment.
This can also be explained in terms of STM failure. Unlike the deep-coded spiderweb that is the LTM, we can only hold so much information in the short-term (there’s even a magical number describing our limits). So let’s say our STM is nearing full capacity when we cross to a different room: our brain has to decide between keeping old information and absorbing new data. Since current information is more relevant for our awareness, the brain automatically decides to erase the whiteboard and start taking notes again.
So, the next time you find yourself standing in a room confused as to why you went there, don’t beat yourself up over it. It is hardly a sign of weak memory or low intelligence. Things slipping out of your mind are the result of “brain glitches” caused by very complex systems developed during hundreds of generations that lived without doorways.
We hope that the next time you forget to bring your flatmate/parent/significant-other a glass from the kitchen, you will recall that there’s a scientifically-sound argument as to why that happened.
- Radvansky, Gabriel & Tamplin, Andrea & Krawietz, Sabine. (2010). Walking through doorways causes forgetting: Environmental integration. Psychonomic bulletin & review.
- Sternberg, R. J. (1999). Cognitive psychology (2 nd ed.). Fort Worth, TX: Harcourt Brace College Publishers.
- Atkinson, R. C., & Shiffrin, R. M. (1968). Chapter: Human memory: A proposed system and its control processes. In Spence, K. W., & Spence, J. T. The psychology of learning and motivation (Volume 2). New York: Academic Press. pp. 89–195.
- Swallow, K. M., Zacks, J. M., & Abrams, R. A. (2009). Event boundaries in perception affect memory encoding and updating. Journal of experimental psychology. General, 138(2), 236–257.
- Lawrence, Z., & Peterson, D. (2016). Mentally walking through doorways causes forgetting: The location updating effect and imagination. Memory (Hove, England), 24(1), 12–20.
- Miller, G. A. (1956). The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychological Review, 63(2), 81–97.