Some retailers, manufacturers and research company Nielsen is testing a new system in US called, Pioneering Research for an In-Store Metric, or P.R.I.S.M. system which measures store traffic using scanners in the aisles and researchers. Some new facts are coming to the fore by using this system like,

People who walk through the salty snacks aisle of a store are more likely to buy something than those who go past the dairy case, and consumers buy more in general when they shop with their kids.

Among other findings from the project are that shoppers are exposed to an average of about 3,500 pieces of marketing stimuli in grocery stores, including displays, packages, televisions and other items; more than 5,000 stimuli at mass merchandisers like Wal-Mart Stores Inc (WMT.N); and about 2,300 at drug stores.

Some more findings include:

Some of the findings are intuitive, Wishart said. For instance, only 13 percent of food shopping trips include kids, but shoppers buy more items when kids are with them.

But surprisingly, the items that had more sales when children were around included soup, water, canned vegetables and hair care items, Wishart said.

And even more surprisingly, the presence of children had little impact on candy sales.

Also, the middle of the day tends to have a higher percentage of people in stores who are not buying anything.

In food stores, 4.5 percent of all purchases happen around 2 p.m., but 7 percent of the store's traffic is seen then, he said.

The produce aisle tends to attract more traffic, while there are "some parts of the store that are virtual wastelands and are not visited at all," Wishart said. Those parts vary by store type and format.

New system looks at US shoppers differently