THE EFFECT OF SYMBOLIC AND NONSYMBOLIC FORMATS ON

THE EFFECT OF SYMBOLIC AND NON-SYMBOLIC FORMATS ON ARITHMETIC IN CHILDREN: A DEVELOPMENTAL FMRI STUDY Lien Peters, Hans Op de Beeck & Bert De Smedt 14/03/2015 – ICPS Conference, Amsterdam

BACK TO BASICS Numerical magnitudes in different formats § Non-Symbolic § Symbolic

BACK TO BASICS Neural model of number processing & arithmetic: Triple Code Model Dehaene & Cohen, 1995, 1997

BACK TO BASICS Arithmetic § Direct route Solution is retrieved from semantic memory (= arithmetic facts verbal code) ? § Indirect route Procedural manipulation need to be performed ( magnitude code)

BACK TO BASICS Number processing § Number comparison task Kaufmann et al. , 2011

BACK TO BASICS Arithmetic § Whole brain activation § Activation ~ task complexity and math ability § All studies used Arabic digits as stimuli Kaufmann et al. , 2011

CURRENT STUDY The neural correlates of arithmetic in symbolic and non-symbolic formats in children ?

WHO? 23 children (9 – 12 years old) § 12 males § Mean age = 10. 67 years old § One discarded in analyses of imaging data, due to excessive movement in the scanner

HOW? Session 1 § Behavioral measures § Dummy scanner: practice round Session 2 § Real scanner

HOW? –SESSION 1 Arithmetic ability § Tempo Test Calculation Reading ability § One-Minute Test § Klepel Intelligence § WISC-III subscales block design & vocabulary

HOW? –SESSION 2 Subtraction task § Number domain up to 10 § Dot patterns, Arabic digits, number words § = or ≠ reference magnitude (4 or 5)

HOW? –SESSION 2 Subtraction task § Block design § 255 seconds per run, 4 runs per participant

BEHAVIORAL RESULTS General measures M SD Min Max 21. 26 64 138 13. 41 43 94 14. 28 41 98 13. 09 2. 65 9 18 11. 45 2. 94 3 19 Tempo Test Calculation 108. 55 62. 86 One-Minute Test 61. 86 Klepel Block Design Vocabulary

BEHAVIORAL RESULTS Behavioral results: subtraction task RT (in s) Accuracy

IMAGING RESULTS Digits – Words – Digits No significant activation Primary visual cortex

IMAGING RESULTS Dots – Digits/Words – Dots Parietal lobule, frontal and occipital areas Angular gyrus & Superior temporal gyrus

IMAGING RESULTS Dots – Digits/Words – Dots Parietal lobule, frontal and occipital areas Angular gyrus & Superior temporal gyrus Manipulation? Retrieval?

CONCLUSIONS Digits ≈ Words § Words > Digits in primary visual cortex probably due to more visual information

CONCLUSIONS Symbolic (Digits & Words) § Superior temporal gyrus & angular gyrus ~ verbal arithmetic fact retrieval? Non-symbolic (Dots) § Superior parietal lobule (≈ intraparietal sulcus) ~ manipulation of quantities?

CONCLUSIONS Difference in neural activation between symbolic and non-symbolic formats might reflect a difference in strategy use (fact retrieval vs. manipulation of quantities)

COMING UP NEXT SEASON Expand subject sample § Children with dyslexia & dyscalculia § Compare neural activation during calculation in different formats with typically developing children

THANKS TO… All children & parents Research unit Parenting & Special Education, KU Leuven Prof. Bert De Smedt Prof. Hans Op de Beeck Research unit Biological Psychology, KU Leuven

THANK YOU FOR YOUR ATTENTION! Questions?