Let’s say there’s a row of street lamps you pass every day while going to and from work. They are, being typical, modern street lamps, of the low-pressure sodium-vapor variety, emitting a red glow at start up and, once they’re operating fully, a steady monochrome yellow. The lamps automatically switch on at sundown, via the activation of a light-sensitive cell, or photocell. The cell is triggered again when sunlight returns at dawn, switching the lamps off. Generally, rather than each lamp having its own photocell, a single photocell is used to control a whole group of street lamps.
You’re returning home from work on what has so far been a completely typical evening, the street lamps illuminating your way as you stroll down the footpath. No one else is around. Oddly, the street lamp nearest you suddenly blinks out, turning on again as soon as you’ve passed it. A level-headed person, you attribute the event to coincidence and think no more of it. Three evenings later, however, while passing the same row of lamps, the phenomenon occurs again. On this occasion, three successive lamps are affected, each one blinking out as you approach, only to suddenly blink on again the moment you step away.
What on earth just happened? Did you influence the lamps with the power of your mind? Or is there a mundane explanation for these events?
Known as street lamp Interference (SLI), experiences of this nature are common, with people in many different parts of the world claiming “that they involuntarily, and usually spontaneously, cause street lamps to go out. Generally the effect is intermittent, infrequent and without an immediately discernable sequence of cause and effect.”
These are the words of the British paranormal scholar Hilary Evans, who, prior to his death in 2011, was the foremost authority on SLI. (“SLIder” is the term he coined to refer to someone who reports a SLI experience.) In addition to being a pictorial archivist and author of numerous books on the Fortean, he helped found, in 1981, the Association for the Scientific Study of Anomalous Phenomena (ASSAP). After receiving numerous reports from people claiming that street lamps respond to their presence in an inexplicable fashion, Evans decided to take on the mystery, collecting hundreds of accounts of SLI through his Street Lamp Interference Data Exchange (SLIDE). The culmination of this research – what turned out to be his final book – is the brief yet highly impressive SLIDERS: The Enigma of Street Light Interference (2010). “SLI… can reasonably be regarded as a phenomenon in its own right,” he argued.
Frankly, when I first heard of SLI I considered it largely insignificant and boring, regardless of whether or not the phenomenon had a paranormal basis. I hastily concluded that most, if not all, SLI experiences could be accounted for as a result of people perceiving connections that have no basis in reality. For, as everybody knows, street lamps can and do malfunction from time to time, and people are bound to walk past them at the moment these malfunctions occur. After taking a deeper look at the phenomenon, however, I came to the unavoidable conclusion that we’re dealing with a genuine mystery – and, what’s more, an important and fascinating one. I agree with Evans when he says: “If true… claims [of SLI] carry profound and exciting implications for science and for our knowledge of human potential.”
It’s time we examined some of those claims.
- Streetlamp Interference: A Modern-day Paranormal Mystery (mysteriousuniverse.org)