There is substantial evidence that extended text written entirely in uppercase letters is read more slowly than text in lowercase. Interestingly, it has been proposed that this uppercase disadvantage applies only to extended text, whereas single words may actually be processed more efficiently in uppercase than in lowercase. Consequently, the use of uppercase letters has been recommended for display labeling where only single words are required. However, it is not obvious why the well-documented uppercase disadvantage for extended text should be reversed for single words.

To examine this issue, we conducted three large-sample experiments (total N = 1065) in which participants read news headlines and single words presented either in lowercase or uppercase under a range of conditions. Across all experiments, a robust and consistent uppercase disadvantage for both news headlines and single words was observed. These findings challenge the view that presenting single words in uppercase facilitates the processing of these words and suggest that the mechanisms underlying the uppercase disadvantage in extended text also affect the processing of single words. Earlier recommendations to use uppercase for single-word display labels should be reconsidered.