why didn’t I look back?

I was at a pelucan crossing over a dual carriageway recently waiting to cross. There was no one else waiting so I approached the control button, But before I could touch iit the ‘WAIT’ sign llit up. I looked around but could see no one either at the other button on my side of the road or the two buttons on the other side. I was surprised and puzzled. Was it a ghost who pushed the button? Or had I managed PK?

What alternative explanations are there? Could the WAIT light have changed automatically? Some lights do change this way but I’ve used this crossing many times and never seen that happen at this crossing. The real answer appeared soon after. A woman overtook me as I crossed the road. I looked around but saw no one else nearby. It seemed clear that the woman had pressed the other button.  

So how had I failed to notice the woman earlier? When the WAIT light came on I was surprised and hesitated before looking around. In that time the woman, having pressed the button, then stepped back behind me. When I first looked round I didn’t look behind me as I expected the person to be near the button. So why would she step behind me? I don’t know but social distancing is a possibility.

But here’s the crucial point. I looked around but NOT  behind me? Why not? Because I didn’t expect there to be someone behind me who had pushed the button. Expectation is an important, but little discussed, factor that can affect witness testimony. We know about the limitations of memory and perception but there is also expectation.  Witnesses will rarely look for the unexpected causes of what is an unexpected event. I might have confidently reported there was no one else there had the woman not passed me on the crossing. And I would have been wrong.