Researchers found that the greater the number of people in favour of or against a policy proposal, the more likely politicians were to take a position that mirrored that opinion, while they were much less likely to be swayed by input from special interest groups.

However, the study also found that politicians were more likely to take a position that mirrored the views of the special interest group if they shared a similar political ideology, raising concerns that some groups may be able to sway like-minded politicians into adopting policies that are opposed by voters. Left-wing politicians, in particular, are responsive to civil society groups.

The study, Responding to whom? An experimental study of the dynamics of responsiveness to interest groups and the public, was co-authored by Professor Anne Rasmussen, of King’s College London, and Dr Simon Otjes, from Leiden University. 

“After all, most of these groups – even those representing societal interests – do not represent the view of the general public and some groups of privileged citizens are better represented by interest groups than the public as a whole.

“However, we observed that some interest groups have the capacity to influence politicians, especially those aligned ideologically, with the risk that these interest groups may sway like-minded politicians into adopting policies that diverge from the general public opinion.”

For the study, the researchers collected responses from more than 2,000 politicians at national, regional and local level in the Netherlands and Denmark, asking them to imagine a scenario in which a proposal to build a new windfarm on land in their constituencies had been lodged.

The politicians were then offered differing supporting information, with some told the proposal was supported or opposed by voters in their constituencies, while others were told that the hypothetical proposal was supported or opposed by a civil society group or business group.

The results showed that, as public support increased for the proposal, so too did the politician’s likelihood of voting in favour of it. In the study, if public support for the wind farm stood at 35 per cent, support among politicians was 48 per cent. If public support stood at 65 per cent, however, corresponding support from politicians rose to 59 per cent.

By contrast, evidence that the views of the politicians were influenced by the positions of business or environmental groups was generally inconsistent, although there was evidence that groups that shared similar ideological views to a politician had a more significant influence. Left-leaning politicians, specifically, tend to be receptive to the input from civil society organizations.

“When politicians are informed that environmental groups oppose the placement of windmills, we also see a stark shift in opinion: the support among left-wing politicians decreases to 53 per cent, a decrease of 14 percentage points, and the support among right-wing politicians increases to 50 per cent, an increase of eight percentage points.”