He told viewers he came up with the idea in 2005.
"Evidently New Zealand's time zone is seven years behind."
Colbert jokingly took issue with one particular aspect of the study.
"My only problem with this scientific study is that it was a scientific study. You see truthiness and empirical evidence don't mix. It's like putting aluminium foil in the microwave - it just angers the magical sprites which heat our food. That's why they take vengeance by spitting fire and voiding my warranty.
"Folks, you can't prove truthiness with information. You prove truthiness with more truthiness. In a process known as truthinessiness."
However Colbert did trust the study - because "it came with a picture of me".
"And that is all the evidence I will ever need."
In the study, participants were shown a series of claims such as "the liquid metal inside a thermometer is magnesium", and were asked to agree or disagree with each claim. When the claim was accompanied by an image, participants were more likely to believe the claim, regardless of whether it was true.
"We wanted to examine how the kinds of photos people see every day - the ones that decorate newspaper or TV headlines, for example - might produce 'truthiness'," Ms Newman said. "We were really surprised by what we found."
The researchers said the findings have important implications for situations in which people encounter decorative photos, such as in the media or in education.
Watch footage of Colbert discussing the issue of truthiness:
- Herald online