3.3.1 Participants
A total of 204 children (103 boys, 101 girls) unselected for ability participated in the study with an average age of 7 years 1 month (SD = 9.42 months, range 5;6 – 8;8 [years; months]): 130 children from two schools in London, England and 74 children from one school in Brisbane, Australia. Children in England were tested on all measures, had an average age of 6 years 2 months (SD = 6.67 months, range = 5;6– 7;8) and were in Year 1 (n =77) and Year 2 (n = 53). Children in Australia were tested on finger gnosis and numerical measures, but not other sensori-motor measures, and were in Year 2 with an average age of 7 years 11 months (SD = 3.88, range = 7;4 – 8;8)1. Children of this age were chosen for consistency with previous similar studies. The schools provided consent for all children in a year group to participate and parents were given the option to opt-out or withdraw their child from the study at any time. Full ethical approval was provided by The University of College London Ethics Committee and the Australian Catholic University Ethics Committee.
1 Note that Australian children showed equivalent scores for arithmetic and other outcomes as those in
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3.3.2 Test and procedures
Children in the UK were assessed on numerical skills (arithmetic, magnitude comparison tasks and counting) sensori-motor skills (finger gnosis, left-right orientation and graphisthesia) and receptive vocabulary. Children in Australia were tested on the numerical tests and the finger gnosis measures only.
The numerical and vocabulary measures were administered in groups whereby all children in a class completed the tests at the same time with instruction from the lead researcher. Teachers and teaching assistants supervised the sessions to ensure all children were concentrating and answering the questions appropriately. Sensori-motor skills were measured individually by the lead researcher and by trained research assistants. These sessions took place in an unused classroom at the school and took a total of 20-30 minutes per child. The order in which the sensori-motor tests were administered was randomised across participants. Children were awarded a sticker for their participation.
Sensori-motor tasks
The sensori-motor tasks, including finger gnosis, were based largely on those used in previous studies but were adapted to improve reliability (e.g. increase number of stimuli) and reduce cognitive confounds (e.g. remove numerical processing).
Finger Gnosis. The finger gnosis test was based on Noël (2005) and assessed a child’s
ability to identify the finger(s) pressed without visual assistance. It was adapted to include a larger number of finger presses to increase reliability. Children placed their hands palm down into a box that covered their hands but allowed the experimenter to see them. The experimenter applied light pressure to the child’s finger between the
nail and finger joint using a stylus. The child pointed to the finger(s) pressed using the index finger of the other hand whilst their hands remained out of their sight.
The test was first administered on the left hand and then repeated with the child’s right hand. There were 25 trials for each hand with one point awarded for each correct trial. No feedback was provided apart from the first five practice items in which single finger presses were administered. The first five test items involved individual finger presses, the second 10 trials involved two different fingers being pressed in succession and the final 10 trials involved two different fingers being pressed simultaneously. In
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the simultaneous trials, children were awarded one point for correctly identifying both fingers but were not awarded a point if they only identified one finger correctly. Similarly, for successive trials, children were awarded a point for correctly identifying both fingers that were pressed although the correct identification did not have to be in the correct order. The maximum possible score on the task was 50.
Left-right orientation. The task used was the same as that used in Noël (2005) and
aimed to measure the child’s knowledge of left and right. There were two components to the task: colour and words which were identical apart from the lack of verbal confounds in the colour version of the task. All children completed the colour task first in which the experimenter tied different coloured paper to their wrists and feet. Facing away from the child, the experimenter asked the child to raise a coloured arm or leg (e.g. “raise your green arm like me”). Then the experimenter repeated this but facing the child. One mark was awarded if the child raised the same body part as the experimenter making a total score of 8 (four points possible when facing away from the child and four points when facing towards the child). Next, the children completed the same task, but the colours were replaced with left or right (e.g. “raise your right leg like me”). Again, one point was awarded for correct responses, with a total of 16 points for both parts of this task. Children were not given feedback and there were no practice items.
Graphisthesia. This task measured the child’s ability to identify shapes through touch
and was adapted from Fayol et al. (1998) to include more shapes and trials and remove numerical confounds. Children closed their eyes and the experimenter traced a shape onto the back of their hand with the tip of a pen. In front of the child was a piece of A4 paper showing ten shapes and the child had to point to the shape that they thought had been traced on their hand. Shapes were simple and verbal such as a square, heart, star and balloon and unlike in Fayol et al. (1998) there were no shapes that could be related to numerical learning (e.g. 4, +, -). Shapes were first traced onto the child’s dominant hand and then the procedure repeated with the other hand. There were ten trials for each hand and one mark awarded for each correct answer; a maximum possible score of 20.
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Arithmetic and number processing tasks
Number tasks were measured using the Test of Basic Arithmetic and Number Skills (TOBANS; Brigstocke, Moll & Hulme, 2016). This standardised measure requires children to complete simple numerical subtests under timed conditions. All children were tested in a group setting and were provided with a booklet to write their responses. Subtests were presented in the following order: addition, subtraction, symbolic magnitude comparison, approximate magnitude comparison and dot counting. For each subtest, there were three practice items for which the experimenter provided the answer once children had attempted the questions.
Arithmetic. One minute was given for each of the addition and subtraction tasks and
30 seconds for all other tasks. Children were instructed to answer as many questions as possible before the instructor said “stop”. Teaching assistants were in the classroom to ensure children were following instructions appropriately and understood the tasks. Arithmetic was a combined score from the addition and subtraction subtest which included items with sums less than 10 (e.g. 3+5 and 7 -3).
Number knowledge. Approximate and symbolic magnitude judgement tasks were used
to assess numerical knowledge. The symbolic task used the digits 1-9 and the approximate task used dots. In the symbolic task, children were instructed to circle the larger of two numbers and in the approximate task, children were instructed to identify the more numerous group of dots from a series of stimulus pairs. Separate scores were created as the total number of correct items for each of these subtests.
Counting. Counting was assessed through a dot counting task in which children had
to count the number of dots (up to 20) in a series of displays and write the associated Arabic numeral. Children scored one point for each correct written answer.
Vocabulary
Receptive vocabulary was assessed using a group-administered test adapted from the British Picture Vocabulary Scale (Dunn & Dunn, 2009). Four pictures were projected onto the classroom whiteboard and children were asked to identify the picture that matched a target word spoken by the experimenter. The items were graded in difficulty and children responded by marking the correct picture in their response booklet. There were two practice items in which feedback was given, followed by 33 test items.
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