WHAT happens in our brains when we watch a compelling TV commercial?

For one thing, certain brain waves that correlate with heightened attention become more active, according to researchers who have used EEGs, or electroencephalographs, to study the brain’s electrical frequencies. Brain waves that signal less-focused attention, meanwhile, tend to subside.

In other words, this is your brain on ads.

Or so say neuromarketers, a nascent group of researchers who use techniques from neuroscience to analyze people’s responses to products and promotions.

Neuromarketing’s raison d’être derives from the fact that the brain expends only 2 percent of its energy on conscious activity, with the rest devoted largely to unconscious processing. Thus, neuromarketers believe, traditional market research methods  like consumer surveys and focus groups  are inherently inaccurate because the participants can never articulate the unconscious impressions that whet their appetites for certain products.

If pitches are to succeed, they need to reach the subconscious level of the brain, the place where consumers develop initial interest in products, inclinations to buy them and brand loyalty, says A. K. Pradeep, the founder and chief executive of NeuroFocus, a neuromarketing firm based in Berkeley, Calif.