Some shoppers swear by their favorite brands. Why are they convinced it's better?

Those who think they're beyond the reach of marketing gimmicks might not have heard of neuromarketing, which is marketing using neuroscience to get you to buy a product.

Some call neuromarketing transformative, while others believe it's unethical because it uses brain imaging to uncover your deepest emotions, then uses the information to create ads that induce you to buy.

Traditional marketing has relied on questionnaires and focus groups to gauge consumers' responses to new and existing products.

Unfortunately, what people think is not always what they say, which makes the marketing data unreliable.

As most can relate, people usually give answers that are more socially acceptable and make them look good.

The data gathered with neuromarketing gives a much deeper and honest assessment of a person's unfiltered reaction to a product.

Several years ago, a group of researchers set out to do their own “Pepsi Challenge” and test whether consumer emotions drive purchase decisions. Scientists put consumers inside a functional magnetic resonance imager while taking the “Pepsi Challenge.”

The imager is a noninvasive test that uses a strong magnetic field and radio waves to monitor blood flow changes in the brain, revealing which areas are active. While being monitored with the imager, people taking the “Pepsi Challenge” did not know which drinks were Coke and Pepsi. Half ended up choosing Pepsi and activated the areas of their brain associated with rational thought.

When participants learned which drink was Coke, the areas associated with emotions were stimulated, and they switched their preference to Coke. This meant positive emotions can overrule rational thought — a result of brand loyalty.

Another method of monitoring brain activity is through electroencephalograms, which measure the electrical activity in the brain. These show certain products also activate parts of the brain that anticipate rewarding stimuli such as food, sex and addictive drugs.

These results have marketers attempting to access and manipulate hidden desires and preferences that reside deep in the brain. They've already begun using electroencephalograms to determine which ads stimulate strong emotions so they will be remembered longer.

Some might ask, is this ethical? Are ads designed using neuromarketing going to have people buying products they don't need, want or cannot afford? Supporters say no ad campaign can turn people into lemmings.

Still, you might want to ask, am I making a rational or emotional purchase?