Observation of directional storybook reading influences young children’s counting direction
Introduction
Cultural differences reflect and reinforce behavioral practices, from social conventions to traffic directions (Berry, Breugelmans, Poortinga, Chasiotis, & Sam, 2011). Our cognitive skills are also shaped by cultural practices, as in the systematic use of physical space for literacy and numeracy. When asked to think about numbers, people often activate a mental number line on which number concepts are represented by increasing magnitude and with systematic direction: In Western cultures, small numbers are associated with left space and larger numbers with right space. Spontaneous associations between number and space were initially described in Western adults (Dehaene et al., 1993, Göbel et al., 2011, Shaki et al., 2012, Wood et al., 2008) and children (Berch et al., 1999, Hoffmann et al., 2013). These associations were initially attributed to a “spillover” from habitual reading direction (Berch et al., 1999, Dehaene et al., 1993). However, the presence of such an association between numbers and space already in preschoolers who are not yet reading fluently (Opfer et al., 2010, Patro and Haman, 2012, Shaki et al., 2012) demands a different explanation for its origin. The current article provides evidence for a novel account that explains the directional nature of this early-developing association between numbers and space in preschoolers and how it differs across cultures.
A general preference for an association between numbers of increasing magnitude and left-to-right space has been found in both preverbal infants (Bulf et al., 2016, de Hevia et al., 2014) and nonhuman animals (Adachi, 2014, Rugani et al., 2010, Rugani et al., 2015). For example, Bulf et al. (2016) showed that centrally presented numerosities bias the visual attention of 8- and 9-month-olds in a directional manner. This shifting of spatial attention was specific for numerical cues and not present for non-numerical cues (small/large shapes). Rugani et al. (2015) reported that 3-day-old chicks trained with an intermediate number of dots subsequently spontaneously associated a smaller numerosity with the left side and a larger numerosity with the right side of space (but see Shaki & Fischer, 2015). This suggests a biological contribution to the association between numerical magnitudes and space that is at some point modified by culture.
In humans, the direction of the association between number and space is influenced by how long adults had lived in a left-to-right reading culture (Dehaene et al., 1993, Shaki et al., 2009). This cultural modulation is also present in other numerical tasks such as counting; whereas the majority of British adults count horizontally aligned objects from left to right, most Arab adults—in line with their predominant reading direction—count them from right to left (Shaki et al., 2012). This cultural contribution has often been explained as reflecting the many hours spent actively scanning text with eyes and fingers (Shaki & Fischer, 2008). Specifically, making repeated horizontal eye movements, often accompanied by directional finger movements, might induce a directional bias in line with the acquired, culturally predominant reading direction. However, the presence of a similar association between numbers and space already in preliterate children requires a modification of this proposed mechanism. An early biologically driven preference to associate small numerosities with left space might be subsequently shaped by cultural (spatial) experiences such as reading (Bulf et al., 2016, de Hevia et al., 2014, Nuerk et al., 2015). This explanation is appealing and covers the majority of available findings. However, it does not explain exactly how cultural experience works to alter the association between numbers and space at such a young age.
Here we tested the role of another cultural experience in the emergence of culture-specific spatial–numerical associations—parents and children reading together. Although preliterate children cannot read, they experience reading-related activities. They monitor adult reading behavior (Dobel, Diesendruck, & Bölte, 2007), pretend to read or write (Sulzby, 1985, Tolchinsky, 2003), and often possess some rudimentary writing skills (Puranik, Lonigan, & Kim, 2011). Storybook reading is a pervasive activity in the homes, preschools, and day-care centers of literate societies. Surveys in the United States (Montag et al., 2015, Raikes et al., 2006) suggest that 30–50% of parents of preliterate children read to their children at least once a day. Even children who do not fully understand reading can be found happily paging through a book (Sulzby, 1985). Thus, both the spatial characteristics of printed materials and the observations of others interacting with such materials are likely influences on the development of the association between numbers and space in preliterate children. This cluster of activities surrounding reading—referred to as reading observation—might shape the direction of an early association between numbers and space. The current studies tested this hypothesis.
Reading observation is beginning to receive attention as a likely mechanism shaping the association between numbers and space in preliterate children (McCrink et al., 2017, McCrink and Opfer, 2014, Nuerk et al., 2015). So far, however, no study has directly tested whether the spatial layout of books, or the observation of others interacting with books, can influence the direction of the association between numerical magnitudes and space in preliterate children. In adults, several studies have shown that the direction of this association can be changed by activating different spatial reference frames (e.g., Bächtold et al., 1998, Fischer et al., 2009, Göbel et al., 2015). For example, Shaki & Fischer (2008; see also Fischer et al., 2009) showed that the strength of the left-to-right association between number and space in bilingual Russian–Hebrew adults varied in line with their recent text reading experience; the association was significantly reduced after reading a Hebrew text (right-to-left reading) in comparison with reading a Russian text (left-to-right reading).
The current studies tested whether two components of reading observation, the culture-specific spatial layout of books and the observation of adults’ interactions with books, shape the directionality of the association between numbers and space in preliterate British and Arab children. In Study 1, we document that the orientation of illustrations shown to infants and young children in commercially available children’s books is highly directional and reflects the written language of the book; English-language books portray actions going from left to right on the page, whereas Hebrew-language books portray events developing from right to left. In Studies 2 and 3, we experimentally demonstrate that the directional cues children receive when parents read a storybook to them modify children’s association between numbers and space. Specifically, we carefully created two versions of a counting storybook (The Very Hungry Caterpillar), differing only in directionality: a left-to-right version and a right-to-left version. We then compared counting direction in preschool children before and after reading observation of the left-to-right versus right-to-left version of the storybook. In both studies, we found significant changes in children’s association of numbers with space. Whereas the picture books used in Study 2 contained a counting activity, we removed any counting from the books for Study 3. Reading observation without any counting observation in Study 3 also led to systematic changes in counting direction. Study 4 shows that directional spatial–attentional shifts, even when accompanied by adult-led gestures, do not systematically modulate the association between number and space. In sum, our results clearly establish reading observation as one mechanism underlying the cultural sensitivity of the preliterate association between number and space.
Section snippets
Study 1: Directionality in children’s books from two reading cultures
We have reviewed above that culture-specific directional spatial mappings for stimuli are present before reading and writing acquisition (Opfer and Furlong, 2011, Shaki et al., 2012). One plausible explanation for these biases is that extensive implicit directional structuring exists throughout preliterate children’s environment. The purpose of our first study was to document the degree of such spatial directionality in children’s books. Thus, we selected an extensive collection of
Study 2: Reading observation and children’s counting direction
The aim of our second study was to test directly whether reading observation modulates subsequent counting direction. We tested preliterate children from two cultures who differed in terms of their culturally predominant reading direction: left-to-right (British) versus right-to-left (Arab) reading. If reading observation is a driver of spatial directionality, we predicted that the manner of reading would modulate the way in which children map number to space in their counting routines. If only
Study 3: Follow-up test of counting direction
Children adapted their counting direction directly after reading observation in Study 2. However, we were concerned that the reading observation in the second study contained a counting activity; the book had discrete objects arranged in a line and the sense of magnitude growing both throughout the storyline as well as within each page (e.g., the caterpillar ate one apple, then on the next page ate two pears, then three plums, etc.). The change in counting direction observed in Study 2, thus,
Study 4: Visuospatial attention and counting direction
The results of Studies 2 and 3 have established that children’s counting is temporarily influenced by their most recent reading observation. This leads us to the question of the way in which reading observation influences counting direction. Reading observation involves a large number of directional cues, such as overt eye movements and associated covert attentional shifts driven by the words on the page, but also the results of joint attention from observing another person looking and pointing
General discussion
Children’s observations of adults reading to them transmit cultural skills. At least two factors contribute to this transmission. First, observing directional interactions with printed materials induces spatial biases in children’s spatial–numerical activities. Second, the illustrations in picture books themselves are culturally shaped and echo the directionality of the written language of a culture.
Children’s spatial–numerical biases reflect their recent directional reading observation. In
Open practices
All data have been made publicly available via Open Science Framework and can be accessed at https://osf.io/fy6ec/.
Acknowledgments
This research was supported by a British Academy/Leverhulme Small Research Grant to Silke M. Göbel and Sam Shaki (SG121544) and by Grant R15HD077518-01A1 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development to Koleen McCrink. We thank Hiba Abo, Joanne Clark, Beth Edlington, Megan Ettenger, Amarelle Hamo, Lama Manzur, Courtney Poole, Hannah Place, Lamisah Wilkinson and Francesca Wood for help with data collection. We thank Maggie Snowling and Charles Hulme for
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