On the Selective Attention of Researchers (or the “No Shit” Effect)

Years back, I saw this video on selective attention. At the time, it blew my mind, and I couldn’t help but constantly bug my poor entourage about it. It shows that when people focus on a task, they can be completely blind to the rest of the world, even when it pokes them right into the face. We observed something similar in the office, involving ping-pong balls, a whiteboard, and a magnetic eraser.

It all started with an equilibrium test. My office mate and I were mourning the loss of our ping-pong table. We were left with sixteen ping-pong balls that had lost their purpose, and we couldn’t help but feel extremely sad for them. So we tried to find them new homes, and our whiteboard’s magnetic eraser turned out to be just the right place.

So after one cute little migrant found its way onto the eraser, a second one came, and soon enough, four of them were neatly aligned on top it. We managed to fit three more on top of those four -pyramid-style, but couldn’t add another layer on top of those three. You see, the eraser is one of those that don’t have an ergonomic grip. Its surface is very smooth, and adding more weight would make the balls from the bottom layer slip to the sides. I am sure that we could make a formal proof showing this, but hey, our group does empirical research! We tried too many times to admit but the observation was always the same: if we attempted to build a third layer, the bottom-most balls would flee in an attempt to regain their freedom.

But eventually, I managed to make it! With the help of tape, a full pyramid soon stood proudly on top of our eraser! My office mate called it cheating, I call it thinking out of the box.


We were curious as to how many people would notice that this pyramid was an impossible construction. So we designed an experiment in which we called various colleagues into our office to ask for their opinion on something written on the board. In case they didn’t notice the pyramid, we designed a second stage to the experiment: we would grab the eraser from beneath the ping-pong balls and use it on the formula they were looking at. The video below illustrates our experimental setting, although with a much lighter content next to the pyramid.

The results of the experiments were quite surprizing! None of our colleagues reacted to the pyramid, no matter how close we put it. For our first participants, we started with a distance of 70 cm between the pyramid and the formula, and ended with 20 cm with our last participant. None of them reacted to the eraser being removed from beneath the pyramid either. They were all focused on their task, and while being completely blind to the bright orange pyramidoidal contraption just next to their faces, they gave good insights on the research written next to it. We have thus confirmed the result of the selective attention test.

We also made another interesting observation. After the end of the experiment, we asked our participants if they had noticed the pyramid. All of the BA and MA students said they did but chose not to say anything, against 50% of the PhD students. 0% of the more senior staff noticed the pyramid, thus proving their greater ability to focus on the one thing that makes sense in their field of view, and automatically discarding the rest. We hypothetize that this is a side-effect of having to deal with too many novel / strange ideas every day. We call this the “no shit” effect.


Having confirmed the selective attention experiment through our ping-pong pyramid test, and shown a correlation between seniority in the field and the intensity of selective attention through the “no shit” effect, we would like to bring your attention to the threats to validity of this piece of side reserach. The main threat to validity is the number of participants. While we had half a dozen PhD students to carry our experiment, we had a grand total of two students and two senior researchers. Another threat to validity is the honesty of the participants admitting to missing the pyramid. But well, we live in the wonderful world of research, so we chose to believe in our participants!