New research suggests a proposed 15 cent levy on disposable coffee cups may not be enough to change consumer behaviour.
The survey of over 1,000 Irish adults found that although 60% support the 'latte levy', just 19% believe it would bring about a change in their own behaviour.
Some 23% believe the tax would change the behaviour of others.
The research - conducted by Amárach Research and Carr Communications - found that four times more waste would be prevented from going to landfill if the levy is introduced along with other behavioural nudges, like discounts on reusable mugs.
While between 70% and 80% rated other measures - such as discounts for using reusable mugs - as being more effective at incentivising them to use less plastic cups.
The study suggests that if the levy were introduced on its own, consumers would use 68,000 less plastic cups every day.
However, if the levy is implemented along with a suite of other measures, 250,000 disposable cups would be prevented from going to landfill every day.
Irish adults buy on average four hot drinks a week - that is two million disposable cups sold every day.
Those aged 16-24 are the biggest spenders in this area.
Image: Carr Communications
Dr Rob Mooney, research director at Amárach, said: "This research demonstrates that while the 'latte levy' may have impact, it would be greatly enhanced by including other behavioural nudges too such as offering discounts to those who use reusable cups, or a refund scheme for the return of plastic cups.
"This study shows how information is framed can effect decision making and behaviour, and how they perceive the effectiveness of the policy change on their own behaviour and the behaviour of others".
When asked how they felt about this proposed 15c levy: 45% of respondants said it was the right amount, 42% felt it was too much, while 13% said the levy should be higher.
The research also revealed how information is framed effects how consumers behave and make decisions.
The researchers tested different ways of wording the questions to understand how that impacts on how people behave and think about issues.
The study found that individuals may react to a choice in different ways, depending on how it is presented to them.
"There are a wide range of biases prominent in decision making - one is how choices are framed," said Amy Hume, behavioural science consultant at Carr Communications.
"In this research we looked at what responses we might elicit simply by framing, or wording, a question or statement differently.
"We found that framing the question in a positive light increases the average response rate sometimes by as much as 20%.
"This suggests that when communicating key policy decisions, such as the 'latte levy', these framing effects are important to consider," she added.
A breakdown of the full findings is available here