Even versus Uneven Right-hand Margins and the Rate of Comprehension in Reading

Comparison was made between the rate of comprehension when reading material presented with justified (i.e. even) right-hand margins with that when reading the same material printed with ragged margins (unjustified). Eighty-six Ss, who had previously been divided into three classes, were tested with the material arranged in short lines of seven words. The style of printing made no difference for good readers, but for the poorer readers the justified style resulted in a significantly worse performance (p≤0.02). Thirty-two poor readers were then tested with the same material arranged in longer lines averaging 12 words, and no disadvantage of justification was found. The findings are explained in terms of the irregularities in spaoing introduced by justification when the line length is short.