Mirror invariance or generalisation is the ability to recognise objects as being the same regardless of their spatial orientation. However, when, for example, learning to read Roman script, children need to hone these skills so that they can readily discriminate between mirror letters such as b/d or p/b. Korean Hangul makes a particularly interesting comparison as it has both lateral and vertical perceptually similar mirror letter pairs (i.e., ㅏㅓ, ㅑㅕ, ㅗㅜ, ㅛㅠ). In the current study, we investigated the mirror generalisation effect in native readers of Korean Hangul. We used a similar negative priming paradigm as used by (Ahr et al., Brain and Cognition 117:1-8, 2017) with Roman script readers. In contrast to their findings, we did not find evidence of negative priming due to either lateral (e.g., ㅏ + ㅓ) or vertical (e.g., ㅗ + ㅜ) mirror letter primes in Korean readers. One explanation for these results is that adult readers of Korean Hangul may not experience mirror invariance to the same extent as Roman script readers due to script-specific characteristics. Thus, learning to read this distinctive script may result in readers being less sensitive to mirror reversals than Roman script readers.
Keywords: Korean hangul; Mirror invariance or generalisation; Mirror letters; Negative priming paradigm; Writing systems.