In a controlled experiment, the UK's Behavioural Insights Team studied the effect stock shots of faces had on the responses of 1 million visitors to the website of a charitable organization.
The researchers found the use of stock photos of people's faces significantly reduced conversions.
They concluded that, because marketers over-expose web users to these kind of photos, users simply tune them out—and ignore any content that accompanies them.
"The use of a stock photo discouraged individuals, who saw it as a marketing gimmick," the researchers said.
