NEW YORK: Marketers looking to engage consumers on mobile should avoid using interstitial ads, which produced some of the most negative responses in two recent neuroscience studies.

One study from Kargo, a specialist in mobile brand advertising, found that interstitial ads – which pop up and block the entire mobile screen – were the most disruptive and intrusive. While "technically" viewable, it said, the attention by a viewer to this format after it is served often drops dramatically.

And MediaBrix, an in-app mobile video advertising platform, reported a similar response to interstitial ads delivered within apps.

"The full page video interstitial ads triggered fight-or-flight responses at a rate twice that of the embedded opt-in ads," it said, adding that "interstitial ad viewers fixated 22% of time spent looking for the X button".

That effect was also reported by Kargo: AJ Mathew, its VP/Research, noted that consumers did visually engage with interstitial ads, "but often because they are trying to close them".

Embedded, opt-in ads, on the other hand, yielded eight times more mental engagement, MediaBrix found, with more than three times the amount of time spent with the brand, and significantly higher brand recall and positive sentiment than standard interstitial video ads.

"Positive indicators like cognitive load, or engagement, and motivation, the brain's manifestation of wanting, were much stronger in the contextualized, rewarded ad, whereas arousal, or erratic sentiment in the brain, was much more common for standard interstitial ads," said Dr. Thomas Ramsoy, one of the lead researchers on the project.

People actually watched the embedded, opt-in units: close to 90% of viewers in the MediaBrix research watched the full 30-second video, compared to only 25% when exposed to an interstitial.

"A shocking amount of mobile ad dollars are going towards boring – or worse, annoying – ads that alienate consumers and negatively impact user experience," said Kargo's Mathew.

Data sourced from Kargo, MediaBrix; additional content by Warc staff