Optimising the effectiveness of container packaging design: How shape influences customer proportion judgments

While brands, advertisements and social media feeds are important routes to attracting and converting customers, packaging can contribute to the overall customer experience. From making a lasting first impression to inspiring positive reviews based on the ‘unboxing experience’, great packaging has the ability to wow customers and set a company apart from its competition. This paper highlights the important role packaging plays in decisions where customers make proportion judgments using packaging containers as references. The authors first introduce a system of psychophysical models to describe how evaluability conditions influence judgments of proportion and pouring volume. The paper proceeds to examine these conditions using laboratory experiments with real adult customers. They show that the elongation of a packaging container causes customers to pour more to reach target proportions, an effect that is maximised when the proportion of content to container is 1/e (or approximately 36.79 per cent). The final section of the paper focuses on the managerial implications. The recommendations will help companies achieve a better understanding of customer visual processing biases and the strategic benefits that container packaging design can offer to a business.