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The Development of the SNARC Effect in 5- to 9-Year-Old Children

Claire Lenehan

+The SNARC Effect

Spatial-Numerical Association of Response Codes

Humans have an internal spatial representation of numbers

Numbers are associated with left-right coordinates

Dependent on cultural and experiential factors

+Discovery of the SNARC Effect

First discovered by Dehaene et al. (1990, 1993)

Detected through a parity judgment task

Response times are faster on the left for small numbers and the right for larger numbers

Magnitude is not necessary for deciding parity, but numerical magnitude is activated automatically

Even Odd

2

Even Odd

1

Odd Even

8

Odd Even

9

+The SNARC Effect in Children

The SNARC effect has been found in American children as early as Grade 3

The effect increases with age (Berch et al., 1999)

Chinese kindergarteners children display the SNARC effect (Yang et al., 2013)

These studies have employed parity tasks, which require automatic numerical magnitude activation

+Van Galen and Reitsma

Employed two different tasks to investigate the presence of the SNARC effect in 7-, 8- and 9-year-old children Gray box detection task Magnitude judgment task

Found that 9-year-old children displayed the SNARC effect on both tasks

7- and 8-year-old children displayed the SNARC effect only on the magnitude judgment task

+Current Study

Adaptation of van Galen and Reitsma’s magnitude task

Goals To determine whether the SNARC effect is present before age 7 To compare the strength of the SNARC effect at different ages

Van Galen and Reitsma did not test children under age 7, but suggested that the SNARC effect would be present as soon as children had mastered the meaning of Arabic numerals

It is expected that all participants will display the SNARC effect, and that the effect will be stronger in older children

+Participants

Four participants Participant 1

Male, Age 5 years 10 months Participant 2

Male, Age 6 years Participant 3

Male, Age 9 years 2 months Participant 4

Male, Age 9 years 4 months

+Procedure

Children were tested individually in their homes

Participants were instructed that, for the purpose of this experiment, numbers smaller than 5 were “small numbers” and numbers greater than 5 were “big numbers”

Flashcards were used to ensure that all participants understood which numbers belonged to which group

Instructions were given orally, then children completed the magnitude task on a laptop computer

+Magnitude Task

PsychoPy software was used to create a magnitude task

Stimuli were the Arabic numerals 1, 2, 3, 4, 6, 7, 8, 9

Participants responded to whether numbers were “Big” or “Small” by pressing designated response keys

The left key was blue and the right key was yellow

There were two blocks of trials, each consisting of 24 or 40 trials preceded by 8 practice trials

+Magnitude Task

Block A Congruent task

“Small” appeared on the left side of the screen in blue “Big” appeared on the right side of the screen in yellow

Block B Incongruent task

“Big” appeared on the left side of the screen in blue “Small” appeared on the the right side of the screen in

yellow

Two participants completed Block A first and two started with Block B

+Results

Block A Block B Difference

Participant 1 1.1847 1.3362 0.1514

Participant 2 0.9739 1.0583 0.0844

Participant 3 1.0063 1.1774 0.1711

Participant 4 0.9994 1.1669 0.1675

Average Response Time (seconds)

+Statistics

A paired two-sample t-test was used to compare the response times in Block A vs. Block B

t = 5.1682, p < .05

An unpaired two-sample t-test was used to compare the results of the 9-year-olds with those of the 5- and 6-year-olds

t = 1.5321, p > .05

+Conclusions

The participants displayed the SNARC effect

Age did not play a significant role in the strength of the effect

+Limitations

The small number of participants makes it difficult to compare children of different ages

The limited number of trials makes it impossible to analyze the results for individual numbers

No gender differences have been found between adults, but there could be differences between boys and girls

The participants may not be representative of the general population

+Questions?