How did you decide on that brand, really? And what was your second choice? Even if you narrowed down to three options by pure rationalism the tiebreaker is often emotional. Then we convince ourselves the decision was objective even when it was not.

The fact that the middle shelf of a supermarket is usually the first one to be empty is quite compelling evidence.

> I guess it’s your first time buying detergent it might work but most people I know have a specific detergent and they buy the same one no matter where on the shelf it moves.

Just to validate that assumption: Would you say this is the same for toilet paper? Soap? garbage bags? Sponges? Pencils? cooking-oil?

There are lots of commodity items I use where I don't know the brand, I cannot even tell how often I switched the supplier of them in the past year...

Subjectively, most people _I_ know buy out of a pool of detergent-brands, all looking quite similar (and most belonging to the same parent company). If they are bombarded with advertisement inside and outside of the shop, and maybe a stacked palette of a different brand of detergent, many of them will "try" this new product instead and end up expanding their pool of brands they will buy.