Dual Dot Sensing of the Eyes

 Is someone looking at you?

 
Introduction

Two visual dots or two small dark spots that lie relatively close together (like eye pupils) are easily noticed by our visual brain, via our eyes. Our brain is built to clearly recognize 2 dots; our visual neuronal circuits then become electrically active. That is why in laboratory images, created by a functional MRI, you will see that specific regions in the subject's brain ‘glow’. These types of perceptual figures form the basis of the more complex visual patterns we can perceive today. 

Dual-dot spotting

How did this perceptual phenomenon of dual-dot spotting originate?
Some of these entoptic forms are deeply embedded in the (genetic development of) neural circuits. For example:
When seeing a large crowd of people at a festival, your brain has the ability to notice which person is looking directly at you. The ability to see two black dots (with a certain distance between them) among hundreds of other patterns has been genetically accelerated during millions of years of evolution (in this example, in human animal species).

The two black dots could also be caused bij the eye sockets that form larger, dark ovals of someone looking your way.
You may also immediately see a blond woman in the picture with two pale eyelids. These are the pseudo-afterimages of two black dots of the pupils (in general).

This brain capacity is encoded in the genetic structure of our ability to process visual sensory stimuli, by means of two factors: 

Two Evolutional Mechanisms

1. Natural selection:
We can immediately see whether a hunting predator or a violent warrior is staring at us. In doing so, early humans acquired better chances of survival because their eyes warned them in advance. Conversely, hunters can immediately see if a prey animal notices that it is being hunted. As a result, early humans did not waste energy on a missed opportunity to acquire food.

2. Sexual selection:
You can immediately see whether a potential reproductive partner shows interest in you. This therefore offers better reproductive opportunities, because eye contact is often an absolute prerequisite for mating rituals; this was already present in early humans; and eye contact still plays an important role today in the very first phase of falling in love. The first step, even before attraction, is seeing each other.

In other words, animals that did not possess this visual recognition ability may have gone extinct long ago, or evolved more slowly.
Animals that do have this observational ability may have evolved faster over thousands of years, partly due to better sexual selection of useful traits.

Incidentally, our brains are also intrinsically highly sensitive to seeing a smile😊.