Simple- consumers believe at the core that the product will fundamentally improve some aspect of life. These types of advertisements are generally for personal grooming, low involvement products like shampoo, body wash and makeup. We known that 'Mascara X' will not lengthen our lashes but our minds find some small bit of believability in the claim.
Here is a prime example of such advertising:
I have indeed purchased this mascara and my eyelashes looked nothing like the commercial's promises. The part that makes me laugh is the line "no false lashes needed"- i disagree! Every single model in this commercial had false eyelashes. However, when I was sitting in the makeup isle at Target I thought of this commercial and decided to give the product a try for $5. In the end Maybelline is looking to drive sales and incremental growth. Success for Maybelline? I'd say so.
Another company that uses this cognitive learning theory is Axe:
With their tagline "Loose the flakes, get the girls", this ad appeals to that fundamental will to improve ones life. The message: girls don't like boys with dandruff so use this shampoo and get the pretty girls. You may watch this ad and laugh, however Axe has had great success with their advertising campaigns because they stick and appeal to that basic need with the very slightest seed of believability.