Tested what, exactly?
I suggest the symbols are morospiles. That's a term from Greek meaning "stupid blemish". This too can be tested: get a bunch of stupid people together to paint on a wall, see what marks they make, measure the degree of similarity to cave art, write a paper about it titled "Maybe They Were Stupid?". Repeat this a hundred times and you've got a field of study to cite authoritatively.
Matching occipital and retinal/purkinje patterns and mapped them to these at scale.
The human mind is so oriented towards pattern matching that we perceive patterns in random noise.
Your statement is a narrative illusion. Science is about pattern seeking and then correlating data about those patterns. They have zilch to do with one another.