Effects of word frequency and length in discrete and serial word reading

When encountering sequences of familiar words (“serial reading”), skilled readers are thought to take advantage of the presentation format by processing multiple words simultaneously in a “cascaded” manner. This is possible when individual words are read “by sight,” similar to naming letters or digits. Accordingly, previous studies have shown that as readers become more experienced, fluent reading increasingly parallels serial naming of familiar symbols, while reading individual words (“discrete reading”) parallels discrete naming. However, most studies have focused on high-frequency, short words, which are more amenable to cascaded processing; different performance patterns across presentation formats (serial vs. discrete) would be expected for longer, less frequent words. Therefore, in this study, we examined how word frequency and length influence the effect of word presentation format and the relation of word reading with serial and discrete digit naming. We tested 201 Spanish-speaking children in Grades 2 and 5 on serial and discrete digit naming and serial and discrete word reading of eight sets of words varying in length (two vs. four syllables) and frequency (high vs. low). Results showed that the serial word presentation format benefitted reading rates across word sets, particularly for short, high-frequency words and more strongly among fifth graders. Furthermore, the difference between serial and discrete reading and its interaction with word length and frequency were more closely associated with serial naming than discrete naming. The pattern of findings supports the hypothesis that readers employ cascaded processing to the extent individual words in the serial reading task are automatized.