Sex differences and variability in phonological sensitivity among primary school children

Sex differences in phonological sensitivity and awareness were assessed using well-established linguistic measures in translation in a two-year longitudinal study on a sample of 136 children during their first two years at school. Girls obtained significantly higher means on a number of measures of phonological sensitivity but not on tests of ability (Coloured Progressive Matrices) (Cohen’s d with Hedges adjustment for sample size = .18). The results suggest that girls possess superior phonological skills on entry to school at age 5 years, are better able to utilise their literacy learning experiences to bring them to bear on phonological awareness tasks, and have a lower variance ratio than boys do. There is some support in this study for the notion that girls have somewhat better developed phonological loop memory skills than boys do. Sex differences and variability in phonological sensitivity among primary school children Vol:7 No.1 2013 www.mreronline. org Faculty of Education University of Malta Msida MSD 2080 Malta 2 Malta Review of Educational Research © Publications Committee, Faculty of Education, 2013 ISSN 1726-9725 Introduction Many contemporary researchers posit the view that there are no differences or only small differences between the sexes in terms of ability. Halpern (2000) clearly states that “sex differences have not been found in general intelligence” (p. 218). This view is shared by other researchers like Brody (1992), Jensen (1998), Lubinski (2000) and Mackintosh (1998). It is therefore established that there are no notable sex differences in general verbal ability, arithmetic, abstract reasoning, spatial visualisation and memory span (Feingold, 1988, 1992). On the other hand, males score higher than females on tests of general knowledge, mechanical reasoning and mental rotations while females score higher than males on tests of language use (Caplan, Crawford, Hyde & Richardson, 1997; Halpern, 2000; Jacklin, 1989; Kimura, 1999; Linn & Hyde, 1989; Linn & Petersen, 1985, Lynn & Irwing, 2004). Even so, these differences have been decreasing over these last generations and it is only in later adolescence that they are marked to any degree (Feingold, 1988). One possibility is that sex differences in verbal learning are minimal or nonexistent during elementary school years, emerging only after puberty when hormonal and psychosocial influences increase (Kramer, Delis, Kaplan, O'Donnell & Prifitera, 1997). If sex differences were present in young children, it would be important to determine if the differences between boys and girls remain constant or if they fluctuate as a function of age or environmental factors. Measures of phonological sensitivity are widely held to be good predictors of later literacy (Bryant, MacLean, Bradley & Crossland, 1990; Ellis, 1990). Phonological sensitivity can be considered to constitute a hierarchy of skills (Adams, 1990; Stanovich, 1992). Higher levels of phonological sensitivity require more explicit analysis of smaller sized phonological units (e.g., phonemes), and more primitive levels of phonological sensitivity require shallower levels of analysis of larger sound units (e.g., syllables). If one were to adhere to this view, phoneme segmentation, phoneme counting, and phoneme reversal tasks represent the higher levels of sensitivity, whereas rhyming or syllable segmentation tasks represent levels that are more primitive. Sensitivity to phonemes is often assumed to have special status in the relation between phonological sensitivity and reading both because it is at this 3 Malta Review of Educational Research © Publications Committee, Faculty of Education, 2013 ISSN 1726-9725 level that graphemes correspond to speech sounds in reading and because individual phonemes do not have a separable physical reality (Lonigan, Burgess, Anthony & Barker, 1998). It is only later when phonological awareness is applied directly to reading and spelling that phonemes start having a separate psychological reality. Sex differences in phonological awareness There is a burgeoning literature on various aspects of sex differences in children’s early literacy but little that is specifically about phonological awareness. Numerous studies support the view that generally, young girls possess higher literacy skills than boys (Coley, 2001; Gambell & Hunter, 1999; Lummis & Stevenson, 1990; Phillips, Norris, Osmond, & Maynard, 2002; Soderman, Chhikara, & Kuo, 1999) but this is by no means supported universally. For example, Davies & Brember (1999) suggest that gender differences occur only among higher-achieving students. Given the general lack of consensus about the issue and the fact that differences found are often limited to specific aspects of ability or achievement that may be circumscribed by issues such as sample size, social class, age or even the methodology used in the study, it is not surprising that the topic retains a degree of interest among researchers. Ready, LoGerfo, Burkam & Lee (2005) provide some inkling as to the possible differences in phonological skills found between boys and girls at an early age. Their study investigated gender differences in a large sample of kindergarten children (8,701 boys and 8,182 girls) and found that girls came to school with an early advantage. Their findings suggest that not only did girls in their sample enter kindergarten with somewhat better developed literacy skills but they also learned slightly more than boys did over the kindergarten year. They attributed these differences to generally more positive behaviours. Part of their study specifically included a basic literacy skills assessment that measured print familiarity, letter recognition, beginning and ending sounds, rhyming sounds and word recognition. All measures are reported to have had high reliabilities. They report that on average, girls entered kindergarten with better-developed literacy skills. There was a difference in the autumn literacy skills assessment that suggested a 0.14 SD (.14 effect size) female advantage at kindergarten entry. Just six months later during the 4 Malta Review of Educational Research © Publications Committee, Faculty of Education, 2013 ISSN 1726-9725 spring literacy assessments, the female advantage widened to 0.19 SD (.19 effect size) with girls having improved their literacy skills faster than boys did. These gender differences are indeed small even if they widen somewhat over the kindergarten year (from 0.14 to 0.19 SD), but they exist nevertheless. Investigating small changes in small differences may be seen as an academic exercise but one cannot ignore the sample size of over 16,000 data sets and the possibility of these small gender differences growing incrementally into larger gender differences over time, by age 16 years. Doctoroff, Greer & Arnold (2006) also report on the relationship between social behaviour and emergent literacy. In their study, subtests from the Developmental Skills Checklist (DSC; CTB, 1990) were combined with other measures of expressive and receptive language skills to create an emergent literacy measure. What is of particular interest is that this composite measure comprised, along with the above measures, tests of phonological awareness and print awareness. These included measures of letter recognition (assessed by children’s ability to name upperand lower-case letters), auditory skills (assessed by children’s ability to identify same versus different sounds), word and sentence segmentation skills, rhyme skills and knowledge of print (knowledge about structure and format of words, differentiating print from pictures and numbers and the identification of components of writing). On a composite measure, albeit adulterated somewhat by other measures for expressive and receptive language, girls outperformed boys once again. In the article by Doctoroff et al. (2006), scores are expressed as z scores but when converted to standard scores, girls obtained 101 scores and boys 98 scores in this emergent literacy measure. The computed effect size expressed in terms of Cohen’s d was . 24, similar to the effect size reported by Ready et al. (2005) but this was probably somewhat inflated due to the inclusion of the receptive and expressive language measures. Before moving on to the research questions posited by this present article and describing the methodology used, one must make mention of some other concepts relevant to this study. One such concept is the phonological loop. Most of the measures administered in this study and indeed in most studies of phonological 5 Malta Review of Educational Research © Publications Committee, Faculty of Education, 2013 ISSN 1726-9725 awareness relied to a greater or lesser degree on auditory memory. The phonological loop consists of a short-term store that is reported to be in place at around age 3 years, one that retains verbal material in terms of its phonological characteristics but also one that is subject to rapid decay (Baddeley, Gathercole & Papagno, 1998; Ford & Silber, 1994; Gathercole & Adams, 1993; Gathercole & Pickering, 1999). Although Vallar & Baddeley (1984) posit the view that the decay of representations in the memory store can be counteracted by serial subvocal rehearsal, this strategic rehearsal process does not emerge typically until about 7 years of age (Gathercole & Hitch, 1993). This means that any phonological assessment of children under age 6 is likely to tap this phonological loop directly. Ardilla & Roselli (1994) and Gathercole & Pickering (2000) report some minor sex differences for central executive mediated items but none for phonological loop mediated memory items in their batteries of measures. Kramer et al. (1997) document some semantic mediated sex differences in recall. This is suggestive of possible underlying cognitive mechanisms for those sex differences reflecting greater overall learning efficiency on the part of the girls. The last issue to be discu