Reading ability underlies the composite effect for Arabic words.

The composite effect, originally demonstrated for faces, has recently been shown to suggest holistic processing of words. The effect is associated with reading fluency in Latin script, but not in nonalphabetic Chinese script, suggesting that script properties influence its relationship with reading expertise. We measured the composite effect for Arabic, a visually complex alphabetic script that offers a useful contrast against Latin and Chinese. Arabic-English bilinguals ($N=$ 24), and English-only readers ($N=$ 22) completed a composite effect task, in which they judged whether the left or right halves of word pairs were the same or different. The unattended half was either congruent or incongruent with the judgement, and the halves were presented in aligned or misaligned blocks. The composite effect, a reduction in the effect of congruency when the halves are misaligned, typically is interpreted as evidence for holistic processing. Arabic-English readers showed the composite effect for Arabic words, whereas English-only readers did not. Both groups showed the effect for English words. The effect size for the two scripts was equivalent in Arabic-English readers. These findings suggest that the composite effect for Arabic words, like that of Latin script words, requires the ability to read the script. Graphemic complexity or the cursive property of the script appears not to play a role in the composite effect in skilled readers.