Just over 90% of shoppers make unplanned purchases, and "about 51% of them take place right in the aisle," Curt Johnson, SVP for the consumer industries division of Miller Zell, tells Marketing Daily. The Atlanta-based retail consulting company recently tracked the buying triggers of 1,000 shoppers. "We were surprised. Because while we've been hearing so much lately about how careful shoppers are being, making lists and doing research on purchases beforehand, there's still a lot of impulse buying."

The study did find, however, that shopping list use is up substantially (65% say they are making shopping lists prior to the shopping trip).

And it turns out that Gen Y is especially likely to do so, and more susceptible to advertising. "People talk so much about this generation researching everything online before they buy it," he says, "but this study showed that they actually index much higher than other age groups in terms of finding all advertising -- both in-store and outside the store -- as 'very effective'."

And Gen Y shoppers are also more likely to make impulse purchases at "end caps," the display at the end of store aisles, as well as along the periphery of stores. "Gen Y is, in fact, a lot more malleable inside the store than many marketers think," he says.

Overall, shoppers believe that ads designed to reach them in stores work better -- giving them a 32% effective rate -- than ads outside the store, which earned a 27% "very effective" rating. About 70% say they responded to end-of-aisle signage, 62% to merchandising displays, 58% to department signage, and 55% to shelf strips.

The study also found key differences in the way that stores trumpet their prices. Sale prices motivated more shoppers (70%) than "everyday low price" positioning (47%.)

Overall, however, some groups are less interested in price than most retailers seem to think. About 93% of Baby Boomers, for example, say they prefer product messages rather than price-point messages while shopping.

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