In a webinar yesterday, Google and MediaVest discussed the effectiveness of overlay advertising in online videos. Research from Nielsen-owned NeuroFocus, a neuroscience lab focused on advertising research, buttressed their report.

Last May, NeuroFocus tracked the reactions of 40 people to YouTube's InVideo overlay and banner ads. (Ads were provided by MediaVest clients.)

Brainwave activity, focus of eyes and skin response helped gauge how ads impacted viewers. Other criteria — attention level, emotional engagement and memory retention — contributed to an overall "effectiveness" score for each advert.

Subjects reportedly found the overlays "compelling and engaging," with high attention and emotional engagement levels met across multiple brands and video types. Used in combination with banner ads overlays rated a 6.6 in effectiveness (said to be a very encouraging score) — slightly higher than banner ads alone, which rated about 6.3.

Brand response also improved when overlays and banners were combined, versus when users saw just banners.

MediaVest SVP Yaakov Kimelfeld, digital research and analytics, claimed the study would be "instrumental in showing that overlays actually work." A contributing factor may be the decline of effectiveness amongst interruptive ads, such as pre-rolls and TV commercials, he added.

Overlays were not pitted against pre-roll ads during the study, but Kimelfeld hinted the comparison could be made in future research efforts.

Overlay ads debuted on Google-owned YouTube in August of last year. At the time, users were given the option to avoid them with a click.

Earlier this month, Google made a quiet change to the program: when users opt to skip overlay ads, the evaded message now appears as a post-roll.