One direction? Cultural aspects of the mental number line beyond reading direction

Spatial-Numerical Associations (SNAs) refer to the demonstrations of spatial processing of numbers. The Mental Number Line (MNL) is a representation model describing numbers as aligning left-to-right (LR) and was suggested to account for directional biases in participants' responses during numerical tasks. One common behavioral demonstration of this is the Spatial-Numerical Associations of Response Codes (SNARC) effect, which describes faster left-/right-hand responses to smaller/larger numbers, respectively. The MNL, and, consequently, directional SNAs, show variabilities across different cultures. Reading direction is considered to be the main factor in explaining these differences. In line with this, individuals with right-to-left (RL) reading habits show a weaker or even reverse SNARC effect. In the present study, we investigated whether SNAs are influenced not only by reading direction, but also by cultural directional preferences such as drawing lines, arranging objects, imagining objects (i.e., rightward or leftward facing), or representing events in time (i.e., mentally representing the past/future on the left/right, respectively). To test this hypothesis, we measured the cultural directional preferences and the SNARC effect across three cultures in an online setup; German, Turkish, and Iranian. LR preferences in the Cultural Directional Preferences Questionnaire were most prominent in German participants, intermediate in Turkish participants, and least prominent in Iranian participants. In line with this, the LR SNARC effect was strongest in German, intermediate in Turkish, and weakest (but not RL) in Iranian culture. These findings suggest that cultural directional preferences are involved in the emergence of adult SNAs in addition to the reading direction.

Directional Scanning of Visual Stimuli

Effect of directional set of horizontal scanning tendencies of visual stimuli was studied on male and female subjects with opposite left-right reading habits. Forty English readers and 40 Hebrew readers (in each group 20 males and 20 females) were presented with horizontal arrays of letter stimuli (either English or Hebrew letters) and of nonletter stimuli (circle and bar patterns) for scanning. Half of the subjects were presented with the letter stimuli first (set condition), and the other half were presented with the nonletter stimuli first (no-set condition). The results showed that experimental set affected the direction of scanning of nonletter as well as of letter stimuli. This effect was usually stronger for males than for females. Differential directional effects were found for English and for Hebrew letters. Reading habits affected performance on the nonletter tests, and interacted with the directional stimulus effects on the letter tests.

Effects of Directional Habits and Handedness on Aesthetic Preference for Left and Right Profiles

Are aesthetic preferences associated with directional reading/writing habits or with cerebral laterality? To answer this question, 138 right-handed and non-right-handed Arabic, Hebrew, and Russian readers were presented with pairs of facial and bodily profiles; one member of each pair was turning to the left, and the other was turning to the right. The participants determined their aesthetic preferences for one member of each pair. If aesthetic preferences are associated with laterality, differential preferences were expected for right-handers and non-right-handers. However, if these preferences are linked to reading/writing habits, differential preferences were expected for Arabic and Hebrew readers who read and write from right to left and Russian readers who read and write from left to right. Data analyses showed that Arabic and Hebrew readers preferred both facial and bodily profiles that turned to the right, whereas Russian readers preferred the profiles that turned to the left. The data were interpreted as showing that aesthetic preferences are associated primarily with reading/writing habits.

Directional Scanning as a Function of Stimulus Characteristics, Reading Habits, and Directional Set

Direction of scanning of horizontally presented visual stimuli was studied as a function of directional stimulus characteristics, subject's acquired reading habits, and experimentally manipulated directional set. Thirty-two English readers and 32 Hebrew readers were shown stimuli with directional characteristics (English and Hebrew letters) and stimuli with no directional characteristics (arrays of different circles, bars, colors, and geometric figures) for scanning. The results showed that, while directional stimulus characteristics affected the direction of scanning of letter stimuli, reading habits affected the strength of these directional scanning tendencies. Nonletter stimuli were found to be differentially affected by reading habits. Experimentally manipulated conditions affected performance, but specific set effect was found for Hebrew readers only. Finally, Takala's finding of subjects' tendency to attend to stimuli in the left visual field was reconfirmed and extended in the present study.

Decreasing variability in the development of graphic production

Several recent theories of development have begun to recognise the importance of variability in mechanisms of change. The present study’s aim was to map variability in the drawing process. We examined changes in cognitive and biomechanical factors that influence drawing behaviour by investigating how simple shapes and complex pictures are drawn. In order to assess changes in variability with age across individuals, children (4- to 7-year-olds) and adults copied a series of geometric shapes and more complex images. In order to assess changes in variability with age within individuals, participants also made repeated copies of simple shapes and characters. Overall, both types of variability decreased with age. It is suggested that increasing biomechanical efficiency and enculturated drawing conventions contribute to these decreases.

How Culture, Age, and Manual Dominance Affect Directionality in Drawing Side View Objects

The aim of the present experiment was to investigate the extent to which the orientation of objects drawn in side view is a function of culture, age, and manual dominance. Right-handed French and Syrian children aged between 6 and 10 years and right-handed adults from the same cultural groups were asked to produce side views of faces, vehicles (car and airplane), self-centered tools with a handle (mug and toothbrush), object-centered tools with a handle (jug and hammer), and animals (dog and fish) using their dominant and nondominant hands. The French participants exhibited a leftward directional bias, whereas their Syrian counterparts displayed a rightward bias. However, no differences between the two cultural groups were observed in the 6-year-olds, who did not present any systematic directional bias in their drawings. Furthermore, regardless of culture, the children did not modify the orientation of the objects in their drawings as a function of the hand used, whereas the hand effect was strong in adults. Finally, despite their directional bias toward the right, the Syrian participants tended to draw the self- and object-centered tools facing leftward. These results are discussed with reference to the current literature on this topic.

Script Directionality Affects Depiction of Depth in Representational Drawings

This research examined the influence of directional reading/writing habits on the representation of depth in a scene. Participants with English vs. Arabic language backgrounds were asked to represent an imagined scene containing two houses, a “near house” and a “far house.” Nearly all participants drew the near house larger than the far house and drew the near house before drawing the far house. However, significant group differences in spatial strategies and movement biases were noted. Whereas the majority of native English readers drew the near house on the left side of the page and the far house to the right of it, native Arabic readers showed a slight right bias in placement of the near house and tended to place the far house to the left of the near house. This effect of script direction characterized right-handed and left-handed users of each group. Taken together, the findings support a cultural account of asymmetries in representational drawing reflecting biases arising from prolonged experience in reading and writing in a particular direction.

The effects of reading-writing direction on the asymmetry of space perception and directional tendencies: A comparison between French and Tunisian children

We compared the influence of reading and writing habits on the asymmetry of space perception and the directional tendencies of French and Tunisian right-handers, aged 5, 7, and 9 years. By comparing two groups of children who use the opposite direction for writing (from left to right for French, from right to left for Arabic), before and after being taught to read in school, we evaluated the impact of writing direction on these asymmetries. A bisection task, a circle-drawing task, and a dot-filling task were used to assess spatial asymmetries and directional tendencies. On the bisection task, a group difference emerged at 9 years, with the French children bisecting the line to the left of the true centre, and the Tunisian children showing no bias. On the circle-drawing task, there was a group difference from 7 years on, as the French children, but not the Tunisian children, used increasing counterclockwise movements. Finally, on the dot-filling task performed with the right hand, the French children filled in significantly more dots when going from left to right from 7 years on, whereas Tunisian children filled in more dots when going from right to left. These results show the impact of basic tendencies in younger children (ipsilateral bias in line bisection, clockwise direction in circle drawing, outward tendency for horizontal displacement in dot filling), as well as the impact of writing direction on spatial asymmetries after learning to read. The results are also discussed in reference to the differences between the two languages, the closeness of the French direction of writing to spontaneous neural-based tendencies, and the influence of learning French at age 8 for the Tunisian children.

Is the future the right time?

Spanish and English speakers tend to conceptualize time as running from left to right along a mental line. Previous research suggests that this representational strategy arises from the participants' exposure to a left-to-right writing system. However, direct evidence supporting this assertion suffers from several limitations and relies only on the visual modality. This study subjected to a direct test the reading hypothesis using an auditory task. Participants from two groups (Spanish and Hebrew) differing in the directionality of their orthographic system had to discriminate temporal reference (past or future) of verbs and adverbs (referring to either past or future) auditorily presented to either the left or right ear by pressing a left or a right key. Spanish participants were faster responding to past words with the left hand and to future words with the right hand, whereas Hebrew participants showed the opposite pattern. Our results demonstrate that the left-right mapping of time is not restricted to the visual modality and that the direction of reading accounts for the preferred directionality of the mental time line. These results are discussed in the context of a possible mechanism underlying the effects of reading direction on highly abstract conceptual representations.

Cultural differences in drawing movements between right-handed Japanese and German participants

Differences in drawing movements with the dominant and nondominant hands by 41 right-handed students from Japan (9 men, 12 women; M age = 20.3 yr., SD = 1.4) and Germany (13 men, 7 women; M age = 23.4 yr., SD = 3.0) were investigated. Participants were asked to use each hand to draw a circle, a pentagon, and a rhombus in one stroke. Analysis showed that Japanese participants drew a circle clockwise with the dominant right hand, starting from 6 or 7 o'clock on the face of a clock, while the German participants drew the circle counterclockwise, starting from 11 or 12 o'clock. Moreover, when drawing a pentagon and a rhombus with the right hand, Japanese participants drew counterclockwise from the top-center vertex, whereas almost half of German participants drew clockwise from the left side and others drew counterclockwise from the top-center vertex. Using the left hand, no significant difference was found in starting positions or directionality. Cultural differences in the starting positions and directionality when using the dominant right hand probably reflect the influence of writing habits on the drawing movement of the dominant hand.

Asymmetries in the perception of facial affect: is there an influence of reading habits?

Perceptions of happy facial affect from asymmetric composite faces presented in free vision were compared in four groups: left-to-right readers (Hindi), right-to-left readers (Arabic), left-to-right and right-to-left readers (Hindi/Urdu) and illiterates (Hindi/Urdu). Right- and left-handed users of Hindi and Urdu were studied. The analysis of asymmetry scores revealed a significant effect of Group, such that a left hemifield preference was present only in the left-to-right (Hindi) group. There were no reliable differences between right- and left-handers. Furthermore, the leftward bias was present in a significantly larger proportion of Hindi than Urdu or Arabic readers. These results are taken to reflect an interaction between a cerebral laterality effect and a directional scanning effect in facial affect judgment.

Directional preferences in perception of visual stimuli

The present paper reviews a series of studies regarding the effects of hemispheric asymmetry and reading and writing habits on directional preferences in reproducing horizontally-displayed visual stimuli. Hebrew readers, English readers, and Arabic readers were presented with arrays of horizontally-displayed directional and nondirectional stimuli, as well as with single stimuli. They were asked to reproduce the stimuli, and the direction of their reproduction, left-right or right-left, was recorded for analysis. Generally, in reproducing arrays of stimuli, English readers showed left-right directionality, whereas Hebrew readers showed right-left directionality. But in reproducing arrays of English and Hebrew letters, subjects of both groups showed left-right and right-left preferences, respectively. However, the right-left directional preferences shown by Hebrew readers were weaker than the left-right preferences shown by English readers. It was hypothesized that these differences are due to differential reading and writing habits acquired in school by English- and Hebrew-readers. In support of the reading and writing habit hypothesis, it was subsequently found that: (a) Arabic readers, who have stronger right-left reading and writing habits than Hebrew readers, show relatively stronger right-left directional preferences, and (b) with the introduction of English as a foreign language in the fifth grade, children show an increase in left-right directionality. Further investigation showed that, depending on the experimental conditions, directional preferences may be a function of either reading and writing habits, or hemispheric asymmetry, or both. Finally, the bearing of these findings on the "nature-nurture" controversy regarding the development of perceptual exploration in children is discussed.

Directional preferences of bilingual children

Effects of simultaneous acquisition of differential reading and writing habits (in English and Hebrew) on directional preferences were investigated for 72 bilingual children in Grades 1 to 6. The children reproduced series of single and multiple stimuli; horizontal directions of their responses were recorded. Increased age was accompanied by growing left-right directional preferences in response to all stimuli but Hebrew letters, for which the reversed right-left preferences appeared. These data corroborate previous findings showing effects of reading and writing habits on directional preferences.

Asymmetry in lateral directionality

Effects of laterality and reading habits on directional preferences were investigated in two experiments. The subjects (N = 40 and 33 in Experiments I and II respectively) were right-and left-handed, male and female Israelis, whose native tongue was Hebrew. They identified and reproduced horizontal arrays of visual stimuli, which were presented either simultaneously (Experiment I), or sequentially (Experiment II). Directional preferences of the subjects' responses were recorded and analyzed. In Experiment I subjects of all groups showed similar, left-right directional preferences. In Experiment II right handers showed right-left preferences, whereas left handers showed inconsistent response patterns. Sex differences appeared among left handers only. The results were interpreted as showing the predominance of reading habit effects in Experiment I, and of laterality effects in Experiment II. It was therefore concluded that, depending on the experimental conditions, directional preferences may be a function of either reading habits, or laterality, or both.

A review of directionality trends in the horizontal dimension as a function of innate and environmental factors

This report reviews research on directionality trends in the horizontal dimension. The literature reviewed shows that such trends are predominantly a function of handedness and acquired reading-writing habits and that innate directional tendencies of left-handers are more influenced by acquired habits than those of right-handers. It is suggested that these trends may reflect some aspect of lateralization of cerebral function and that in mature adults the mixed-dominance left-handers are more influenced by environmental factors than are right-handers. Suggestions for future research include utilization of larger samples of left-handers and employment of longitudinal studies which systematically vary handedness and reading and writing habits. It is also suggested that controls for lateral dominance should be established. In addition it is suggested that reading and writing habits can be broken down into component parts and that their influence on directionality should be examined.