My mom tells a story of the day she believes she watched me learn object permanence. I was playing with a farm set; I’d drop all of the people and farm animals out of sight behind the barn, then gleefully move it to prove my toys were all still there. We all figure out at a very early age that our moms, our dads, our toys and everything else are persistent objects that we can see again and again. We learn this feature of reality well before we are aware of our own thought process, so most of us never a chance to reflect on how fundamental this concept is to our cognition, or what life might be like if our minds worked differently.
At the level of physics, our eyes receive a continuous input of photons of various colors. The arrangement and combination of colors is never exactly the same twice. Lights flicker, shadows shift, angles change, and yet through all of that we resolve images which we identify as persistent objects even though the images may be subtly or even substantially different. And so when we see a car drive past us, say, we understand it as the same car moving and not just a series of images of similar looking cars. Now, research suggests that ability is connected to our ability to form long-term memories. Tracking a moving object provides us a richer set of visual data about what that object looks like from different angles and in different lighting. It seems reasonable that such data would provide a foundation for improved memory; there’s simply more information for our memory to work with.
What really struck me from this story though was the flip side of the finding. When objects moved erratically on a video screen, they weren’t remembered as well as objects that conformed to our unconscious expectations of how objects should move. Those expectations make it possible to infer that what we are seeing is the same object and track it; we are relying on what we know about how objects move and how they don’t move. When an object moves contrary to those expectations, it is presumably more difficult to infer whether it is a single object or multiple distinct objects. Consequently we can’t collate all the visual data into a single memory.
And so I began to wonder in what other ways our expectations shape our memories. What ideas, experiences, observations don’t quite fit into our way of thinking and so slip from our mental grasp? For example, I have friends who have two kids and it took me a long time to get the kids’ names straight. Since I’m usually better with names and since we see them regularly, I found my struggle curious. The only explanation I could think of was that I expected their names to be in alphabetical order so that the older kid had the name starting with ‘S’ and the younger the name starting with ‘T’ and so I kept swapping them.
I’d like to provide other examples, but it’s awfully tricky to remember what I don’t remember. Anyone else find it harder to remember things which don’t match your expectations?
About the author:
Andy has worn many hats in his life. He knows this is a dreadfully clichÃ©d notion, but since it is also literally true he uses it anyway. Among his current metaphorical hats: husband of one wife, father of two teenagers, reader of science fiction and science fact, enthusiast of contemporary symphonic music, and chief science officer. Previous metaphorical hats include: comp bio postdoc, molecular biology grad student, InterVarsity chapter president (that one came with a literal hat), music store clerk, house painter, and mosquito trapper. Among his more unique literal hats: British bobby, captain's hats (of varying levels of authenticity) of several specific vessels, a deerstalker from 221B Baker St, and a railroad engineer's cap. His monthly Science in Review is drawn from his weekly Science Corner posts -- Wednesdays, 8am (Eastern) on the Emerging Scholars Network Blog. His book Faith across the Multiverse is available from Hendrickson.