The intuitive use of contextual information in decisions made with verbal and numerical quantities

Verbal and numerical formats (e.g., verbal: ‘low fat’, or numerical: ‘20% fat’) are used interchangeably to communicate nutritional information. However, prior research implies that verbal quantities are processed more intuitively than numerical ones, and are more influenced by contextual information. We tested this hypothesis in two pre-registered experiments measuring three correlates of intuitive processing: (i) response time, (ii) decision performance, and (iii) the level of interference from a concurrent memory task. Influence of contextual information was inferred from participants’ decision patterns. Participants imagined they had consumed a given amount of a nutrient (represented in a pie chart) and decided whether a new quantity (either verbal or numerical) could be eaten within their guideline daily amount (GDA) in a mixed design varying format, concurrent memory load, nutrient, quantity, and GDA fit. Critically, memory load did not affect decisions with verbal or numerical quantities, and participants were not consistently faster with verbal quantities. Participants’ decisions were less accurate and more influenced by contextual information (i.e., the identity of the nutrient involved) when presented with verbal than numerical quantities. These results suggest that the processing of verbal and numerical quantities do not necessarily differ in terms of intuitive and analytical processing styles, however verbal quantities are more influenced by information that may be less helpful for making accurate decisions about quantities.