Irregular stimulus distribution increases the negative footprint illusion.

As a climate change mitigation strategy, environmentally certified 'green' buildings with low carbon footprints are becoming more prevalent in the world. An interesting psychological question is how people perceive the carbon footprint of these buildings given their spatial distributions in a given community. Here we examine whether regular distribution (i.e., buildings organized in a block) or irregular distribution (i.e., buildings randomly distributed) influences people's perception of the carbon footprint of the communities. We first replicated the negative footprint illusion, the tendency to estimate a lower carbon footprint of a combined group of environmentally certified green buildings and ordinary conventional buildings, than the carbon footprint of the conventional buildings alone. Importantly, we found that irregular distribution of the buildings increased the magnitude of the negative footprint illusion. Potential applied implications for urban planning of green buildings are discussed.