I’m interested in how and why people see and believe in things that are considered by most people not to exist. I’ve done a lot of reading about optical illusions, mind tricks, expectation, the power of suggestion, misidentification and how the brain acts on its own to generate caricatures and make sense of incomplete information.

Though realizing that humans often do make errors, I’ve often found it hard to understand how a person can actually see something that isn’t supposed to be there – especially something at fairly close range – unless it’s actually there.

We all remember times we’ve mistaken strangers, lookalikes, for people we know, for example. But as much as I’ve tried, I haven’t been able to catch more dramatic examples of this sort of misperception operating in myself.

But on a recent trip to Quebec I was finally able to experience something of this phenomenon – catching it just after the fact.

I was travelling on the freight ship Bella Desgagnés in the Atlantic, along Quebec’s remote Lower North Shore. We had stopped for a few hours at the small Innu First Nation village of La Romaine, and I got off to get some air and stretch my legs. I ended up going for a long walk along the rocky shoreline towards a small, enclosed bay, which I could only see the mouth of. A thin veil of fog covered the area. But visibility was relatively good.

At one point I noticed a rowboat with two fishermen in it floating in the mouth of the bay, just ahead. But I paid the boat little heed. I was more interested in the beach and shoreline, looking at the colourful rocks, twisted driftwood and skeletons of dead crabs.

Minutes later, I looked out again towards the water and saw a large rock exactly where I had seen the fisherman just before. I was puzzled – where had they gone? Perhaps further into the bay? As I followed the turn in the shoreline and found myself looking towards the head of the bay, I saw neither the punt nor the fisherman. They had completely vanished. If the boat and its crew were actually there before, they had disappeared – which was an impossibility.

It dawned on me that I must have mistaken the rock in the water for the boat. Or my brain did, rather. I had seen many fishing punts in Quebec over the previous two weeks – so my brain conjured up that image, that pattern, automatically. It took a perceptual shortcut. Triggered in part, perhaps, by the ambiguity resulting from the light fog.

It made me wonder how often things like this happen in our everyday lives – but go undiscovered. And how our perceptual mistakes, visual and otherwise, COLLECTIVELY impact on the world.