Brand names typically maintain a distinctive letter case (e.g., IKEA, Google). This element is essential for theoretical (word recognition models) and practical (brand design) reasons. In abstractionist models, letter case is considered irrelevant, whereas instance-based models use surface information like letter case during lexical retrieval. Previous brand identification tasks reported faster responses to brands in their characteristic letter case (e.g., IKEA and Google faster than ikea and GOOGLE), favoring instance-based models. We examined whether this pattern can be generalized to normal sentence reading: Participants read sentences in which well-known brand names were presented intact (e.g., IKEA, Google) or with a modified letter case (e.g., Ikea, GOOGLE). Results showed a cost for brands written in uppercase, independently of their characteristic letter case, in early eye fixation measures (probability of first-fixation, first-fixation duration). However, for later measures (gaze duration and total times), fixation times were longer when the brand's letter case was modified, restricted to those brands typically written in lowercase (e.g., GOOGLE > Google, whereas Ikea less than or similar to IKEA). Thus, during sentence reading, both the actual letter case and the typical letter case of brand names interact dynamically, posing problems for abstractionist models of reading.
