In a world where individual actions can contribute to slow down or accelerate climate change, people’s perceptions of the environmental impact of these actions play a key role in their decisions. For example, if you think that using ChatGPT consumes a lot of energy, you are likely to limit your use of it. Conversely, if you believe your car is fuel-efficient or produces less pollution than it actually does, you are more likely to use it more frequently. In other words, our beliefs about environmental impact directly influence what we do.
However, assessing the true environmental impact of our actions is not as straightforward as it seems. Most processes that generate emissions or consume resources are complex, invisible and difficult to compare. Is it more polluting to produce a kilo of meat or to transport fruit from another continent? How much energy does an internet search actually consume? Faced with these questions, we tend to simplify matters and rely on external cues to help us make quick decisions. And it is precisely in this process that cognitive biases can arise.
One way in which these perceptions can be altered is through the labelling of products and services. Previous research has shown that serving a burger alongside an apple labelled as ‘organic’ can lead us to believe that the environmental impact of both foods is even lower than that of the burger alone, as if the sustainable production of the piece of fruit somehow compensated for the burger’s environmental impact. The label acts as a cue that simplifies our judgement: if it is “eco”, we automatically assume it is better. But what would happen if we had objective information to assess the environmental impact of a product labelled as “eco”? Would we really be able to judge it accurately, or would the label continue to influence our interpretation of the data?
To explore the extent to which this type of signal can distort our perceptions, we conducted an experiment using a fictional scenario. Using a computer-based task, we showed 199 anonymous participants the changes in a neighbourhood’s monthly carbon footprint over the course of a year. The data was presented visually in a simplified format: participants could see how emissions fluctuated month by month around an average value.
At one point, several new houses were built in the neighbourhood. As might be expected, this led to an increase in the overall carbon footprint, as more homes mean higher energy consumption and, consequently, higher emissions.
This is where we introduced the key variable of the experiment. Half of the participants were told that the new homes had eco-certification, meaning they were labelled as environmentally friendly. The other half were not given any additional information: they simply viewed the new homes without any further details. Apart from that detail, both groups received exactly the same information.
The results indicated that simply describing the houses as eco-friendly led to a bias in the assessment of their environmental impact. Participants who saw the houses with an ‘eco’ certification tended to consider that these contributed less to the neighbourhood’s carbon footprint, compared with those who did not see the label, despite looking at the same data. In other words, the label did not change reality, but it did change perception.
These findings highlight the problem arising from practices such as ‘greenwashing’, which involves emphasising or exaggerating the positive environmental aspects of a product or service to make it more appealing, even though its actual environmental impact is not as low as suggested. If, as our study shows, eco-labels can lead to an underestimation of environmental impact, there is a risk that well-meaning consumers will make less sustainable choices.
In a world where sustainability is becoming increasingly important, understanding how our perceptions of environmental impact are formed is essential. Labels can oversimplify a complex reality. That is why, beyond labels and certifications, it is important to foster a critical and informed perspective that enables us to make responsible decisions.
Reference
Moreno-Fernández, M.M., Blanco, F., & Matute, H. (2025). Eco-friendly labeling biases judgments of environmental impact. Journal of Environmental Psychology, 106, 102715. https://doi.org/10.1016/j.jenvp.2025.102715
Contact at the CIMCYC:
Manuela Moreno-Fernández (@email)
Fernando Blanco (@email)