Political communications researcher Dr Jacob Groshek, together with co-investigators Noortje de Boer and Hannah Sütfeld, analysed 144 online campaign ads produced for more than 11 candidates during the 2012 French and American presidential elections, including the Republican primaries in the US.
The study found slightly more than 60% of American ads possessed a negative tone, compared to just 7% of French ads.
The vast majority of French advertisements (68%) were deemed to be 'neutral' in tone, while just 18% of US ads resided in this category.
In addition, unofficial advertisements that were created by amateur media producers for US politicians were the most negative on average, with 13.4 negative statements and images per ad, whereas unofficial, non-professionally created ads for French politicians were typically most positive (only 4.5 negative statements and images on average).
"This study indicates that non-professional media creators in America are pushing the boundaries of attack advertising beyond the already harsh and highly visible climate of animosity present in the advertising put forth by candidates themselves," Dr Groshek said.
"These findings are squarely at odds with some previously held ideas about the democratising potential for online communication to reinvigorate American politics.
"But on the other hand, the findings do align with a growing body of research that suggests prevailing political and media cultures are adaptive and re-negotiated in online social media spaces."
Dr Groshek, from the University's School of Culture and Communication, said his findings applied across the left-right ideological divide in both countries.
The research -- published online at First Monday and one of the first peer-reviewed studies to analyse the 2012 US election -- assigned an average 'negativity score' to each analysed politician, based on the average number of negative statements and images in their ads:
The 'most negative'.
Ron Paul (15.9), US
Rick Santorum (11.4), US
Mitt Romney (8.8), US
Marine Le Pen (8.6), FRA
The 'most positive'.
Christine Boutin (7.8), FRA
Newt Gingrich (7.8), US
Nicolas Sarkozy (8.0), FRA
Barack Obama (8.2), US
François Hollande (8.5), FRA