Left-Right and Up-Down Mirror Image Confusion in 4-, 5- and 6-Year-Olds

doi:10.4236/psych.2013.410104

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Psychology

2013. Vol.4, No.10, 736-740

Published Online October 2013 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2013.410104

736

Left-Right and Up-Down Mirror Image Confusion in 4-, 5- and

6-Year-Olds

Izumi Uehara

Department of Psychology, O chanomizu University, Tokyo, Japa n

Email: [email protected]

Received July 24th, 2013; revised August 26th, 2013; a ccepted September 28th, 2013

bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the

original work is properly cited.

Young children under the age of 8 - 9 years tend to confuse left-right mirror images, and it is thought that

their linguistic skills play a crucial role in this phenomenon. However, other aspects of this confusion,

such as whether children confuse up-down mirror images or whether the meaningfulness of the stimulus

influences matching performance, remain unclear. The present study examined the confusion of left-right

and up-down reversed images by 4-, 5- and 6-year-olds using meaningful and meaningless figures in a

task in which sample and comparison stimuli were presented simultaneously. Children performed more

accurately when presented with meaningful figures and confused both up-down and left-right reversed

figures, although they did so less frequently in response to up-down than to left-right reversed figures.

Reversal confusion was greatest in 4-year-olds and no significant differences were observed between 5-

and 6-year-olds. These findings suggest that the ability to discriminate reversed images may be associated

with the development of a wide range of cognitive abilities including theory of mind, executive function,

and suggestibility.

Keywords: Preschool Children; Left-Right and Up-Down Mirror Image Confusion; Meaningfulness

Introduction

It is well-known that young children under 8 - 9 years of age

experience difficulty when discriminating left-right mirror im-

ages (e.g., Bryant, 1973; Cohn & Stricker, 1979; Cronin, 1967;

Davidson, 1935; Jordan & Jordan, 1974; Thompson, 1975). A

number of previous studies have used letters, such as “b” versus

“d” and “p” versus “q”, to investigate reversal discrimination

and, as a result, it is thought that there may be a correlation

between the reading and writing skills of children and their

performance on left-right reversal discrimination tasks (Cohn &

Stricker, 1979; Cubelli & Della Sala, 2009; Davidson, 1935;

Fisher, Bornstein, & Gross, 1985; Jordan & Jordan, 1974, 1990;

Terepocki, Kruk, & Willows, 2002).

McMonnies (1992a; 1992b) found that mirror image confu-

sion in children is correlated with factors other than linguistic

skills and suggested that left/right body awareness may be a

latent factor. Jean-Paul and Youssef (2012) suggested that other

tasks, such as those that require writing a letter in a specific

location on a sheet of paper, may also influence the mirror

writing of children. Furthermore, meaningfulness has some

influence on mirror image discrimination. Mandler and Stein

(1974) found that children 7 - 8 years of age recognize reversals

of meaningful pictures more accurately than expected, although

this study did not include meaningless pictures as control stim-

uli. Outside of this classic study, the relationship between the

meaningfulness of a stimulus and mirror image confusion lacks

supporting evidence and, to date, the causes of mirror image

confusion in children and the mechanisms underlying this phe-

nomenon remain unclear. Thus, it is important to explore the

possible factors other than linguistic skills such as reading and

writing, that influence mirror image confusion in preschool

children who have not yet fully developed reading and writing

skills.

A number of previous studies have used lines and figures to

investigate the discrimination of images by preschool children

(Bryant, 1973; Corballis & Zalk, 1977; Cronin, 1967; Rude1 &

Teuber, 1963; Thompson, 1975). However, the type of stimuli

that elicit confusion in preschool children and the extent of such

confusion remain ambiguous. Likewise, the discrimination of

up-down mirror images is much less documented than is

left-right reversal discrimination. Several initial studies indicate

that up-down discrimination is easier for young children than

left-right discrimination (Davidson, 1935; Huttenlocher, 1967;

Rude1 & Teuber, 1963; Thompson, 1975), but these studies do

not clarify whether preschool children confuse up-down rever-

sals in a matching-to-sample task involving novel stimuli. Ad-

ditionally, virtually no studies have investigated up-down dis-

crimination in young children. Thus, the extent to which chil-

dren confuse up-down reversed images and the age at which

such confusion occurs compared with the extent to which they

confuse left-right reversed images and the age at which that

confusion occurs remain ambiguous.

Thus, the present study examined the extent to which pre-

school children confuse original figures with left-right and

up-down reversals of these images and whether their perform-

ance in response to meaningful versus meaningless figures

differs. To compare responses to left-right and up-down re-

versed images, each child was asked to perform a simultaneous

matching-to-sample task by selecting a stimulus from a set of

I. UEHARA

comparison stimuli that included both left-right and up-down

reversed stimuli.

Method

Participants

This study included 42 4-year-olds (12 boys and 30 girls;

mean age: 4 years and 2 months; range: 3 years and 8 months to

4 years and 6 months), 41 5-year-olds (24 boys and 17 girls;

mean age: 5 years and 2 months; range: 4 years and 7 months to

5 years and 6 months), and 45 6-year-olds (26 boys and 19 girls;

mean age: 6 years and 2 months; range: 5 years and 7 months to

6 years and 6 months) from a nursery school in a suburb of a

large city near Tokyo. All were middle-class, Japanese-speak-

ing children. This study was conducted under the supervision of

the school, and written consent from the parents of participants

was obtained through the school prior to the participation of

their children. All children who participated in this study did so

voluntarily and none dropped out before the study was com-

pleted.

Materials

Ten stimulus sheets (210 mm × 297 mm) were used for the

test (explained in the next section), and four were used for

practice trials that were performed before the test trials. A sam-

ple stimulus was presented in the upper half of each stimulus

sheet, and six comparison stimuli were presented in the lower

half in a 2 × 3 layout (see Figure 1). The six comparison stim-

uli were comprised of the same figure as the sample stimulus

(in the upper half), a left-right reversal of the sample stimulus,

an up-down reversal of the sample stimulus, and three figures

that appeared similar to the sample stimulus. Each of the three

figures differed from the sample stimulus in a few respects. For

example, if the sample were a shirt, one of the comparison fig-

ures would have a crooked sleeve and another would not have a

collar (Figure 1).

Thus, 10 sample stimuli and 60 (10 × 6) comparison stimuli

were used for the test trials, whereas four sample stimuli and 24

(4 × 6) comparison stimuli were used for the practice trials. The

10 sample stimuli in the test trials consisted of five meaningful

figures and five meaningless figures used by a previous study

(Uehara, 2012) in which seven elementary school children

(aged 7.6 - 9.3 years) correctly chose all the meaningful and

meaningless figures. Meaningful figures included a shirt, a cup,

and a boot, and meaningless figures were geometrical figures

(a) (b)

Figure 1.

Illustration of the placement of stimuli on a test sheet. A sample

stimulus was placed on the upper half of the paper, and six com-

parison stimuli were placed on the lower half. a) An example of

meaningful stimuli. b) An example of meaningless stimuli.

consisting of lines and curves (Figure 1). The four sample

stimuli in the practice trials were simple meaningless figures

and were never used in the test trials. All figures were prepared

by computer software and hard copies were used for the ex-

periment. The presentation order of the 10 test sheets was ran-

domized across participants, and the locations of the six com-

parison figures on each sheet were also randomized for each

participant.

Procedure

Each participant performed the task in a quiet classroom

during his or her free time during the regular school day. Before

the test trials, each subject completed four practice trials and

received feedback after each response. By the end of the prac-

tice trials, the researcher confirmed that each participant under-

stood the task requirements: namely, to choose the figure that

looked most similar to the sample.

For the test trials, the researcher presented each child with 10

figure sheets one at a time. The researcher asked the child to

choose the comparison figure that was most similar to the sam-

ple figure by asking the child, “Which figure looks most like

this figure?” Children responded by pointing with their finger.

The test trials did not include feedback concerning the accuracy

of the response; rather, the same verbal prompt was given each

time, “Well, then, next.” All participants finished the test trials

in approximately 3 - 5 minutes.

Results

Preliminary analyses did not reveal any sex differences in

accuracy or error type; thus, sex was not considered in the fol-

lowing analyses.

Effects of Age and Meani n gf u ln e s s o n

Matching-to-Sample Performance

The mean correct response rate of the children was plotted as

a function of age and meaningfulness (Figure 2), and only an

exact match-to-sample response was considered correct. A

three (age: 4-, 5-, or 6-year-old) × two (meaningfulness: mean-

ingful or meaningless) analysis of variance (ANOVA) revealed

statistically significant main effects for age (F[2,125] = 53.7,

39.5

70.2

79.1

32.9

61.0

75.1

100

4-year-old 5-year-old 6-year-old

M ean percen t ag e o f corr e ct an swers

Age

meaningful

meaningless

Figure 2.

The mean correct response rate plotted as a function of age (4-year-olds,

5-year-olds, and 6-year-olds) with meaningfulness (meaningful or

meaningless figures) as a parame ter. Error bars indicate standard errors.

I. UEHARA

p < .01, partial η2 = .46) and meaningfulness (F[1,125] = 8.79,

p < .01, partial η2 = .07). No significant interaction between age

and meaningfulness was observed (F[2,125] = .46 p > .05, par-

tial η2 = .00). Post hoc multiple comparison tests for age

(Tukey HSD, p = .05) revealed a significantly poorer perform-

ance by 4-year-olds compared with 5-year-olds and 6-year-olds

and by 5-year-olds compared with 6-year-olds. These findings

indicate that older children performed better than younger ones

and that children performed more accurately in response to

meaningful than to mea nin gless figures.

Analysis of Errors: Choice of Left-Right Mirror

Images

To investigate whether children erroneously chose the

left-right reversed stimuli more frequently than expected by

chance (chance level: 16.7%), one-sample t-tests were con-

ducted. Children in each age group chose the left-right reversed

stimuli significantly more frequently than chance in response to

both meaningful and meaningless stimuli: 4-year-olds for

meaningful stimuli: t(41) = 7.37, p < .01; 4-year-olds for

meaningless stimuli: t(41) = 9.40, p < .01; 5-year-olds for

meaningful stimuli: t(40) = 4.40, p < .01; 5-year-olds for mean-

ingless stimuli: t(40) = 4.65, p < .01; 6-year-olds for meaning-

ful stimuli: t(44) = 4.29, p < .01; 6-year-olds for meaningless

stimuli: t(44) = 2.08, p < .05). In other words, when children

failed to choose the exact match, they chose the left-right re-

versed stimulus more frequently, regardless of meaningfulness.

Differences in the choice of left-right mirror images accord-

ing to age and meaningfulness were also assessed. The mean

response rate of the children when choosing left-right reversed

stimuli was plotted as a function of age and meaningfulness

(Figure 3). A three (age: 4-, 5-, or 6-year-old) × two (mean-

ingfulness: meaningful or meaningless) ANOVA revealed a

statistically significant main effect for age (F[2,125] = 14.8, p

< .01, partial η2 = .19) but not for meaningfulness (F[1,125] =

1.71, p > .05, partial η2 = .01) or for the interaction between

these two factors (F[2,125] = 1.94 p > .05, partial η2 = .03).

Post hoc multiple comparison tests for age (Tukey HSD, p

= .05) revealed a significantly greater number of choices of the

left-right reversed stimulus by 4-year-olds than by 5-year-olds

31.0

16.116.0

29.5

17.6

8.0

100

4-year-old 5-year-old 6-year-old

Mean percentage of left-right reversal

answers

Age

meaningful

mean i n gless

Figure 3.

The mean response rate of children choosing left-right reversed fig-

ures plotted as a function of age (4-year-olds, 5-year-olds, and 6-

year-olds) with meaningfulness (meaningful or meaningless figures)

as a parameter. Error bars indicate standard errors.

and 6-year-olds. No significant difference was found between

5-year-olds and 6-year-olds. These findings indicate that young

children aged 4 - 6, especially 4-year-olds, often confused fig-

ures with their left-right mirror images regardless of meaning-

fulness.

Analysis of Errors: Choice of Up-Down Mirror

Images

To investigate whether children erroneously chose the

up-down reversed stimulus more frequently than expected by

chance (chance level: 16.7%), one-sample t-tests were per-

formed. Only the 4-year-olds chose the up-down reversed

stimulus significantly more frequently than would be expected

by chance regardless of meaningfulness: for meaningful stimuli:

t(41) = 3.83, p < .01; for meaningless stimuli: t(41) = 8.02, p

< .01. The 5-year-olds and 6-year-olds chose the up-down

stimulus significantly more frequently than would be expected

by chance in response to meaningless but not meaningful stim-

uli; 5-year-olds for meaningful stimuli: t(40) = 1.53, p > .05;

5-year-olds for meaningless stimuli: t(40) = 4.39, p < .01;

6-year-olds for meaningful stimuli: t(44) = .16, p > .05;

6-year-olds for meaningless stimuli: t(44) = 5.83, p < .01. In

other words, when children failed to choose the exact match,

4-year-olds chose the up-down reversed figures more fre-

quently than expected by chance regardless of meaningfulness,

whereas 5-year-olds and 6-year-olds chose the up-down re-

versed stimulus more frequently than expected by chance only

in response to meaningless figures.

The mean response rate of children choosing the up-down

reversed stimuli was plotted as a function of age and meaning-

fulness (Figure 4). A three (age: 4-, 5-, or 6-year-old) × two

(meaningfulness: meaningful or meaningless) ANOVA re-

vealed statistically significant main effects for age (F[2,125] =

10.1, p < .01, partial η2 = .14) and meaningfulness (F[1,125] =

36.7, p < .01, partial η2 = .23). The interaction of these two

factors was not significant (F[2,125] = .38, p > .05, partial η2

= .00). Post hoc multiple comparison tests for age (Tukey HSD,

p = .05) indicated a significantly greater number of choices of

the up-down reversed stimulus by 4-year-olds compared with

5-year-olds and 6-year-olds. No significant difference was

13.3 6.83.6

25.2

15.1 14.2

100

4-year-old5-year-old6-year-old

Mean per centag e of up-dow n rever sal

answers

Age

me aningfu l

me aningless

Figure 4.

The mean response rate of children choosing up-down reversed figures

plotted as a function of age (4-year-olds, 5-year-olds, and 6-year-olds)

with meaningfulness (meaningful or meaningless figures) as a parame-

ter. Error bars indicate standard errors.

738

I. UEHARA

observed between 5-year-olds and 6-year-olds. These findings

indicate that children, regardless of age, chose up-down re-

versed figures more frequently in response to meaningless than

meaningful figures and that 4-year-olds chose meaningful

up-down reversed figures more frequently than did older chil-

dren.

Analysis of Errors: Left-Right Reversed Stimuli

versus Up-Down Reversed Stimuli

The relative frequencies of choosing left-right and up-down

reversed stimuli were compared. For meaningful figures, a

three (age: 4-, 5-, or 6-year-old) × two (reversal direction:

left-right or up-down ) ANOVA revealed statistically signifi-

cant main effects for age (F[2,125] = 12.5, p < .01, partial η2

= .17) and reversal direction (F[1,125] = 33.8, p < .01, partial

η2 = .21). The interaction between these two factors was not

significant (F[2,125] = 1.14, p > .05, partial η2 = .02). Post hoc

multiple comparison tests for age (Tukey HSD, p = .05) indi-

cated a significantly greater number of choices of reversed

stimuli by 4-year-olds than by 5-year-olds and 6-year-olds, but

no significant difference was found between 5-year-olds and

6-year-olds. In other words, children, regardless of age, chose

meaningful left-right reversed figures more often than they

chose meaningful up-down reversed figures when they failed to

choose the exact match. Additionally, 4-year-olds chose both

meaningful left-right and up-down reversed stimuli more fre-

quently than did 5-year-olds and 6-year-olds.

In terms of meaningless figures, a three (age: 4-, 5-, or

6-year-old) × two (reversal direction: left-right or up-down)

ANOVA revealed a statistically significant main effect for age

(F[2,125] = 23.8, p < .01, pa rtial η2 = .28). No main effects for

reversal direction (F[1,125] = .01, p > .05, partial η2 = .00) and

no interactions between these two factors (F[2,125] = 2.02, p

> .05, partial η2 = .03) were observed. Post hoc multiple com-

parison tests for age (Tukey HSD, p = .05) indicated a signifi-

cantly greater number of choices of the up-down reversed

stimulus by 4-year-olds than by 5-year-olds and 6-year-olds,

but no significant difference was found between 5-year-olds

and 6-year-olds. In other words, the difference in the selection

of meaningless left-right and up-down reversed figures was not

significant, and 4-year-olds chose both meaningless left-right

and up-down reversed stimuli more frequently than did 5-year-

olds and 6-year-olds.

Discussion

The present study investigated confusion in preschool chil-

dren when selecting left-right and up-down mirror images of

figures by including meaningful and meaningless figures within

the same paradigm. Consistent with previous studies, left-right

reversal confusion was frequently observed in children regard-

less of meaningfulness. Specifically, 4-year-olds confused

original figures with their up-down reversals regardless of

meaningfulness, whereas 5-year-olds and 6-year-olds confused

only meaningless figures. With regard to meaningful figures,

children confused the originals with their left-right reversals

more frequently than with their up-down reversals; this differ-

ence was not significant for meaningless figures. This type of

confusion was more frequently observed in 4-year-olds com-

pared with 5-year-olds and 6-year-olds, and we found no dif-

ference in the confusion of 5-year-olds and 6-year-olds.

Matching-to-sample performance improved with age between 4

and 6 years, and children performed more accurately for mean-

ingful than meaningless figures.

The present study provides new basic data and insights re-

garding reversal confusion in young children, and these data

suggest that several critical aspects of phenomenon have been

overlooked in children. First, up-down reversal confusion in

children has rarely been investigated, and knowledge concern-

ing this phenomenon is very limited. In the present study, pre-

school children confused not only left-right but also up-down

reversed images. Additionally, up-down reversal confusion

decreased earlier than did left-right reversed confusion. As

left-right reversal confusion, such as in mirror writing, is com-

monly observed when children begin to learn to write, research

tends to focus on its relationship to linguistic skills. However,

up-down reversal confusion in writing tasks has rarely been

investigated in children. The current findings suggest differen-

tial associations between up-down reversal confusion and

left-right reversal confusion, on the one hand, with linguistic

development, on the other, such that up-down confusion de-

pends on factors other than linguistic skills, such as directional

or visuospatial sense, whereas left-right confusion depends

more on linguistic skills.

Less frequent reversal confusion for meaningful relative to

meaningless figures suggests that meaningfulness influences

difficulty during the differentiation of stimuli. Thus, if children

are encouraged to find meaning in shapes or figures, they might

be less confused by reversed shapes. Previous studies indicate

that children younger than 8 - 9 years tend to confuse left-right

reversed letters. Based on the present findings, the ability to

find meaning in a word or to imagine a word from a letter may

contribute to avoidance of left-right reversal confusion. How-

ever, the ability to only pronounce and/or copy the target letter

may not be enough to reduce confusion about the left-right

reversal of a lette r.

The difference in performance between 4-year-olds and older

children suggests that the development of reversed image dis-

crimination may be related to other types of cognitive func-

tioning. Similar abilities known to be related to age differences

are theory of mind (e.g., Perner, et al., 2007; Perner & Ruffman,

1995), appearance-reality distinction (e.g., Flavell, Green, &

Flavell, 1986; Sapp, Lee, & Muir, 2000), suggestibility (e.g.,

Bruck & Ceci, 1999; Leichtman & Ceci, 1995; Uehara, 2000),

executive function (e.g., Lyons & Zelazo, 2011; Zelazo & Frye,

1998), and other functions (e.g., Gerstadt, Hong, & Diamond,

1994; Povinelli, Landau, & Perilloux, 1996; Uehara, 1998).

However, the relationships among these abilities remain unclear.

Zelazo (2004) proposed that reflective consciousness develops

together with metacognitive skills and that this development

could lead to the control of thought, emotion, and action. The

development of metacognition and/or self-reflective con-

sciousness may be one factor involved in the changes in per-

formance that have been observed over a wide range of cogni-

tive abilities, including reversal differentiation. In this manner,

the use of conscious metacognitive judgment may lead to an

avoidance of confusion when stimuli have similar appearances,

such as with reversed images. Further investigation is necessary

to elucidate the specific mechanisms underlying this process.

In conclusion, the present study demonstrates that, although

the documented relationship between left-right confusion and

linguistic skills is important, other factors also play critical

roles in reversal confusion in young children.

I. UEHARA

740

Acknowledgements

This research was supported by MEXT KAKENHI Grant

Numbers 19730457. I thank Ikuya Murakami for his thoughtful

comments on earlier versions of this paper and his help in sub-

mitting this paper. Most of all, I am grateful to the children and

teachers at the nursery school for their cooperation.

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