DIVE summary:

• Traditionally, marketers have relied on what customers say about their product, but that is unreliable as focus-group subjects try and please the testers by overstating their affinity for a given product.
• Marketers are getting around that by setting up virtual shelves for focus-groups and tracking their eye movement, resulting in a heat map.
• Retina tracking shows that a bigger picture isn't always better.  It showed that eyes can process images so quickly that picture size is of less importance.
• Use of this technique resulted in Axe changing its bottle shape from curved to shaped, and changed the placement of their logo.  You can see the two bottles here.

From the article:

Consumer-products companies are turning to new technology to overcome the biggest obstacle to learning what shoppers really think: what the shoppers say.

It turns out consumers aren't a very reliable source of information about their own preferences. Academic research has shown focus-group subjects try to please their testers and overestimate their interest in products, making it hard to get a read on what works. But getting testing right is crucial for consumer-products companies because they ship high volumes and lack direct contact with shoppers.