Phonological similarity between words is represented in declarative memory as spatial distance.

Space can be used as a metaphor to describe semantic and perceptual similarity. Research has shown that similarity and spatial information can influence each other. On the one hand, similarity entails spatial closeness; on the other hand, proximity leads to similarity judgment. This spatial information can be stored in declarative memory and measured later on. However, it is unknown if phonological similarity/dissimilarity between words is represented as spatial closeness/distance in declarative memory. In this study, 61 young adults were tested on a remember-know (RK) spatial distance task. Participants learned noun pairs on the PC screen that were manipulated concerning their phonological similarity (similar vs. dissimilar) and reciprocal spatial distance (near vs. far). In the recognition phase, old-new, RK, and spatial distance judgments were asked. We found that for hit responses in both R and K judgments, phonologically similar word pairs were remembered closer compared to phonologically dissimilar pairs. This was also true for false alarms after K judgments. Lastly, the actual spatial distance at encoding was only retained for hit R responses. Results suggest that phonological similarity/dissimilarity is represented respectively with spatial closeness/distance and that this information is stored in the neurocognitive system of declarative memory.