Viewers' "brains are working harder" when they consume content on YouTube than they are when they view broadcaster video-on-demand platforms such as Channel 4's All 4 – but this isn't necessarily good for advertisers on YouTube.

That's according to researchers commissioned by Channel 4 to investigate consumer behaviour while watching on- demand.

Sharing details of the latest Channel 4 "In VoD we trust" study at the Esomar market research conference in Dublin last week, Rob Ellis from the firm Cog Research said viewers are more likely to be "in a relaxed, fluid state" when watching programmes and advertisements on All 4.

When we consume content in the more cluttered visual environment that is YouTube, however, we tend to be “in a distracted, planning state”, he said. We are figuring out what to do or watch next.

Cog Research and neuroscientist Dr Amanda Ellison set out to measure, using eye-tracking and skin conductance response (SCR) technology, the way viewers respond to video- on-demand on different devices in their homes. The study, which involved 36 people, was conducted when Channel 4's on-demand platform was still called 4oD. (It became All 4 in March.)

At the Esomar conference, Ellis presented film footage that showed participants’ eyes were centred on the screen of their devices when they were watching 4oD, while their focus was a little more scattered when the content was from YouTube. Advertisements on 4oD garnered 3½ times the attention levels of YouTube ones, the study found.

Channel 4 research executive Lucy Antoniou said advertisers needed to know how to "separate the wheat from the chaff" in a crowded video- on-demand landscape. Its next neuroscience-influenced study will look more closely at how different demographics consume All 4 content and how attention and engagement levels vary depending on the type of device.

Buyers of advertising naturally look for evidence to back up Channel 4’s claims that All 4 is a captive medium, and therefore a “premium” one for advertisers.

“They need to be convinced,” said Ellis. But the research confirms something intuitive, he adds. “The reality is that when we watch programming and advertising on devices we are very attentive.”