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Handedness is the natural or biological
preference for using one hand more than the
other in performing special tasks depending
on which hemisphere is dominant for the task
(Rice, 1998). People are said to be right
handed if they use right hand most of the time,
and left handed if they prefer left hand. People
are referred to be ambidextrous, if they use
both hands equally well and approximately on
equal amount of the time.
Correlation of biological traits with the
handedness proves the relationship between
handedness and biology (Jaffe, 1998).
Cerebral cortex of the forebrain, which controls
intellectual, motor and sensory functions, is
divided into two hemispheres with a
contralateral control of the body. The two
hemisphere of the brain each perform
specialized functions. Lateralization is the
preference for using one side of the body more
than the other in performing special tasks
depending upon, which hemisphere is
dominant. The reason why lateralization occurs
Effect of Handedness on Intelligence Level of Students
Saba Ghayas and Adnan Adil
University of Sargodha, Sargodha, Pakistan
The present study aimed at finding the effect of handedness on intelligence
level of students. The sample consisted of 150 intermediate, graduate, and post-
graduate students of Sargodha district including an equal number of left and right
handers. Laterality Assessment Inventory and Raven Standard Progressive Matrices
Test were used to assess handedness and intelligence respectively. Results
indicated that left handed participants were significantly more intelligent than the
right handed participants (p < .05) and time taken by the right handers was
significantly greater than that of the left handers (p < .05). ANOVA showed
nonsignificant difference between the intelligence of students at different educational
levels.
© Journal of the Indian Academy of Applied Psychology,
January 2007, Vol. 33, No.1, 85-91.
is not yet clear (Rice, 1998). Lateralization is
biologically programmed from the day a baby
is born. This dominance and preference of one
of the two hemispheres is directly connected
with the body’s preference of handedness and
it is immutable (Cardwell, 2003).
As handedness is biologically and
genetically linked, so it has various effects on
one’s behavior and abilities. There are
different points of views about its effects.
Popular culture has become fond of the idea
that people and their native abilities may be
described as either right or left brained. No
doubt left handedness is associated with a lot
of disadvantages but various studies have
shown that left-handedness is also associated
with enhanced abilities. Increase in ratio of left-
handers can produce a corresponding
intellectual advance and leap in the number
of mathematical sporting or artistic geniuses.
The reason is that right handers have genes
that force their brains into a slightly more one
sided structure but brains of left handers are
86
more symmetric where the two sides are more
equal which enhances person’s abilities
(McManus, 1997).
Left-handedness is also more common
among musicians mathematician, professional
baseball and cricket players, architects and
artists (Rice, 1998). Typically left handed
people are seen to be more creative, more
likely to notice the size, shape and form of
things, more likely to see the whole picture or
concept. All these in amalgamated form show
that left-handers have more power of
perception as compared to right-handers.
McManus (2002) also worked on the power of
perception of left and right-handers. Different
studies indicate that various qualities of the
left-handers show the tendency of high IQ level
and it is also assumed that handedness have
some relationship with the intelligence level.
Many researchers have tried to study the
brain functioning of intelligent people. These
studies suggest that brains of highly skilled
and intelligent people require less glucose
energy while performing certain cognitive task.
Highly intelligent people also tend to take in
information more quickly and to show faster
brain wave response to simple stimuli such as
flash of light (Papilia, 1993).
There are some studies in which speed of
processing has been directly linked to central
nervous system functioning and to intelligence
(Vernon, P.A, & Mori, M. (1992). Intelligence,
Reaction times and peripheral nerve
conduction velocity as cited in Bee, H. (2000).
The developing child. (9th ed.). Boston: Allyn
and Bacon). Research shows that the speed
with which people are able to retrieve
information is related to intelligence. In general
people with higher IQ scores react quickly on
the information processing and perceptual
task (Hunt,1997). Studies have shown that
during perceptual tasks, right hemisphere is
more activated so intelligent people may have
more specialized right hemisphere (Barlow,
2001). Intelligence is not a consistent construct
from the birth till the death. There are different
factors, which contribute to the inconsistent
nature of IQ.
It is considered that left-handers are more
intelligent than right-handers because of
different abilities which naturally exist in them
but some studies proved that the average
intelligence of left handers is fractionally lower
than that of right handers; though at the top
end of the intellectual spectrum they do better
(McManus, 1997). Some researchers have
been working on this subject and are
convinced that the proportion of left handers
is rising and left handed people as groups
have historically produced an above average
quota of high achievers (McManus, 2002). Left-
hander’s brains are constructed differently in
a way that widens their range of abilities and
the genes which determine that left-
handedness also govern development of the
language centers of the brain. According to
McManus (1997), the increase in the
proportion of left-handedness could produce
a corresponding intellectual advance and a
leap in the number of mathematical, sporting
or artistic geniuses. A significant advance in
the analysis of brain-behavior relationships
was made by the research and these
investigations showed that left hemisphere
lesions tend to be associated with lower verbal
than performance IQ on the Weschler scales
(V < P). In pattern (V > P) predominately in
groups with lesions in the right hemisphere
and with diffused brain damage (Reitan, 1955).
Annett and Marian (1993) gave the theory that
individuals heterozygous for the right shift
gene are intellectually advantaged. The bulk
of research on the topic leads to new findings,
some directly contrary to assumptions of
related to strong relationship of left-
handedness and intellectual giftedness.
A study was done on Annett’s theory that
left-handedness is maintained by a balanced
polymorphism and left-handers are
intellectually more advantaged. In this study
Effect of Handedness
87
(N= 429) undergraduates were given tests
assessing hand preferences, hand skill, skill
asymmetry, and intellectual ability. Results
showed no evidence to support Annett and
Marian contention that handedness is
maintained as a balanced polymorphism by
the intellectual advantage shown by
heterozygous relative to homozygote (Annett
& Marian, 1993).
In a thorough review of the research on
handedness and intelligence, it is concluded
that there was no consistent link between IQ
and handedness (Cole, 1997). As a whole left-
handed people are not more or less intelligent
than right handed one’s, and on average both
are equal (Needleman, 2001). Research has
shown that there is nonsignificant relationship
between the handedness and intelligence,
and there is no difference between left-
handers and right-handers in terms of
intelligence and abilities that can be detected
(Hurlock, 1978).
It has been proposed that perception has
direct relationship with the intelligence of a
person and studies have indicated that
perceptual power of left-handers is more
specialized than that of right-handers because
of the dominance of right hemisphere (Myers,
2001).
Educational experiences are positively
correlated with scores on IQ tests and
informational processing task. Nevertheless,
most IQ differences that are of concern are
those that are well within the normal range and
might be systematically modified by optimal
structuring of the learning environment
(Murphy, 1998). Different studies acknowledge
a crucial role for environment in the
development of intelligence and it is further
supported that IQ can be improved by training.
It is stated that IQ influence by the length of
time person passed in school so indirectly it
means that education affects the level of
intelligence (Steinberg, 1990).
Researchers investigated IQ test
performance with respect to the educational
level, health, and mood states. Factor analysis
revealed that IQ test performance was
dependent primarily on education and to a
lesser degree health and mood. At post-test
education became an even mere significant
factor and health and mood more non
significant factor (Gunther, Christiana &
Gunther, 1981).
The review of literature about the abilities
and traits of left-handers indicate their high
intelligence level but because of inadequate
research, the results are not conclusive. The
present study was conducted in order to find
the relationship between the handedness and
intelligence of students. It was, therefore,
hypothesized that the left-handers would have
higher levels of intelligence and would
demonstrate higher speed of information
processing. The study further explored the
impact of education on the intelligence of
students. Method
Sample
A sample of 150 students including equal
number of left-handed and right-handed
students was drawn from various schools,
colleges and universities of Sargodha district
by purposive sampling (N = 150, mean age =
19.6 years). The sample was gender free and
was divided into three groups of equal size
with respect to educational level which ranged
from intermediate to post- graduate. All the
participants were treated in accordance with
the “Ethical Principles of Psychologists and
Code of Conduct” (American Psychological
Association, 1992).
Instrument
The handedness of the students was
assessed through the administration of
Laterality Assessment Inventory (Sherman &
Kulhavy, 1976) which has been found to be a
valid and reliable instrument for the
Saba Ghayas and Adnan Adil
88
assessment of laterality. Raven Standard
Progressive Matrices Test (Raven, 1938) was
administered in order to measure the
intelligence of left and right-handers. The
RSPMT has consistently been found to be a
reliable and valid measure of intelligence.
Raven Standard Progressive Matrices Test
(RSPMT) consists of 60 problems divided into
5 sets, each of which comprises of 12
problems; arranged in ascending order of
difficulty. The score on RSPMT ranges from
zero to sixty.
There is a large accumulation of published
research on RSPMT; the studies are scattered
and heterogeneous, having been designed for
a variety of different purposes. In general
retest reliability of RSPMT in groups of older
children and adults that were moderate
homogenous in age ranges approximately from
.70 to .90, which shows the high reliability of
this test. Internal consistency reliability co
efficient is mostly in the 0.80 and 0.90s
correlation. A study was done on the
correlation of RSPMT with the other verbal and
performance tests and results showed the
coefficient .40 and .75 respectively several
factorial analysis suggest that the RSPMT is
heavily loaded with a factor common to
intelligence measures ( Anastasi, 1997).
Procedure
The participants of the study were
personally contacted. Before administering the
Raven Standard Progressive Matrices,
required personal information was obtained
through the demographical sheet and the
confidentiality of their information was ensured.
They were briefed regarding the nature and
objectives of the study.
The participants were asked to take
RSPMT according to the instructions written
at the beginning of the test. Test was
administered in 75 separate setting and in
each setting one left and one right hander
took the test, by choosing the suitable option
or item in all the sixty problems. The
participants were apprized for their
cooperation and support in the study.
Results and Discussion
In order to determine the differences in the
intelligence level of the participants, t-test was
applied on the scores of left and right-handed
subjects. The obtained score of the present
study ranged from 12 to 57. Findings revealed
that the major hypothesis of the study was
supported as the left-handers turned out to
be more intelligent than the right-handers {t
(148) = 2.15, p < .05}
The results of the present study are
consistent with earlier work on hundred
thousands and twelve participants (Bower,
1993). The specified age of participants was
thirteen years. Results identified nearly 300
participants who were high scorer on the
Scholastic Aptitude Test (SAT). Twenty percent
of these top-scoring participants were left-
handers. The approximate proportion of left-
handers in the general population is 10% and
the finding of the study showed the ratio of
left-hander top scorers twice the ratio of left-
handers in the general population. Due to
negative attitude towards the left-handedness,
people are not ready to assume that
left-handedness can contribute to higher
intelligence level. Annett, & Manning, found
that the highest means were in children with
(R-L) difference. The costs of rs++ genotype
seemed to include risks to verbal as well as
non-verbal qualities, that is, intelligence. This
prediction was confirmed for the sample of the
Table-1: Mean, Standard Deviation and t-
Values of Students’ Scores on RSPMT
(N = 150)
Handedness n M SD t
Left-handers 75 44.2 8.80 2.15*
Right-handers 75 39.8 12.36
df = 148,* p < .05
Effect of Handedness
89
study; scores for Raven Progressive Matrices
and for several tests of education progress
was significantly poorer in mild dextral, the
overall trends in all cases being a decline from
left to right across the R-L continuum.
Time taken by the students during the
performance on intelligence tests was
analyzed with reference to their handedness.
The time taken by the students during the test
(RSPMT) ranged from 5 to 75 minutes. The t-
test demonstrated a significant difference in
the amount of time consumed by the left and
right handed students in accomplishing the
RSPMT as right-handers significantly took
more time for the accomplishment of test than
the left-handers {t (148) = 2.88, p < .01}.
Table-2: Mean, Standard Deviation and t-
Values of Time Taken by Students in
Accomplishing RSPMT (N = 150)
Handedness n M SD t
Left-handers 75 32.44 13.92 2.88**
Right-handers75 40.24 12.13
df = 148,** p < .01
Thus the second hypothesis of the study
i.e., the time taken by the right handers would
be greater than that of left handers was
supported The speed of the accomplishment
of the test elucidated that the perception of
left-handers is faster than that of the right-
handers. In a study of split brain patient in
relevance to left and right-handedness, all the
participants were given same perceptual
tasks. Left-handed patients rearranged some
blocks easily to match a drawing but when the
right-handed participants tried to match the
same drawing, they made many errors (Sperry,
1982). This study indicates the perceptual
superiority in the left-handers and supports
the present findings. From physiological
viewpoint, it has been documented that when
a person performs a perceptual task, the
activity level of brain waves, blood flow and
glucose consumption increases in right
hemisphere (Feldman, 2003). In the brains of
right-handers, left hemisphere is dominant
whereas in the brains of left-handers right
hemisphere is dominant, the right hemisphere
dominance can also be a factor for the higher
speed of information processing of left-
handers because right hemisphere controls
all the perceptual functions of the body (Myers,
2001). The present findings revealed the same
i.e., the right-handers had lower perceptual
speed because of which they took more time
during the accomplishment of test.
The acceptance of afore mentioned
hypotheses of the present study supports
each other, as researchers have showed that
intelligence and information processing speed
has a direct relationship. Different researches
showed that perceptual speed is enhanced in
intelligent people (Richard, 1991). Perceptions
of stimulus in highly intelligent people reflect
greater neurological speed. Repeated studies
showed that the brain waves of intelligent
people register a simple stimulus more quickly
and with creative complexity (Barlow, 2001).
The study revealed that intelligent people have
high creativity levels. Other related studies
tend to support the view that intelligence and
creativity are not exclusively independent
characteristics (Lugo & Hershey, 1974). It is
viewed that in general, people with high
intelligence scores do well on the creativity
tests (Myers, 2001).Creativity and intelligence
both are not always dependent upon each
other but it is evident from researches that
highly intelligent people do any task with more
creative complexity.
Subjects of the study were divided into three
groups with reference to their educational
level, which were intermediates, graduates,
and postgraduates. The score on the
intelligence tests of all three groups were
analyzed comparatively.
Table-3: Means and Standard Deviations
of Scores of Students of Different
Educational Level on RSPMT (N = 150)
Educational level MSD
Intermediate 39.33 10.08
Graduate 41.41 13.35
Postgraduate 43.93 9.01
Saba Ghayas and Adnan Adil
90
One-way analysis of variance revealed that
there is no effect of educational level on
intelligence level of students {F (2, 147) =
1.38, p = n.s}. The results were contrary to
the hypothesis of the present study, i.e., the
participants with high education level would
score higher than the students with lower
educational level. The findings of the study
resembled with a study done by Woodworth
(1949) to perk up his tests and principle test
for literate men. Some of the men tested, did
not get good scores because of inadequate
schooling. Some achieved grade one scores
who had not even completed grammar schools
and some college graduate made only average
scores. More imperative is the fact that a great
young men who proved exceedingly intelligent,
had not gone beyond the secondary school.
From the results of present study it is evident
that intelligence cannot always accrue with the
educational level. An extensive body of data
has accumulated showing that over the
elementary high school and college period
performance on intelligence tests is quite
stable (Bernstein & Hogarty, as cited in
Anastasi, 1997). Education gives knowledge
and knowledge contributes to intelligence. It
is the application of knowledge rather than just
possession of it, which plays a crucial role. It
means intelligence level of a person cannot
be predicted on the basis of his qualification
or academic degree.
Research instrument that has been used
in the present study, might have contributed
to the findings of present study. Raven
Standard Progressive Matrices Test involves
the apprehension of figures and in
apprehending these figures education and
knowledge does not play vital role. In
performing the other standardized intelligence
tests, knowledge play important role as
compared to RSPMT such as Wechsler Adults
Intelligence Scale (Wechsler, 1955).RSPMT
consists of figures which does not require
much knowledge but majority of other tests
consists of those items which need specified
knowledge.
The participation of students with different
academic achievement record might have
contributed to the rejection of fourth
hypothesis. The departments that have high
merits of admission than those of others also
participated in the study. The students with
bright academic record and high achievement
level are common in these departments. It is
considered that educational success is
correlated with the intelligence level (Rice,
1998); therefore their involvement might also
afflict the results of the present study.
Conclusion and Suggestions
The results of the present study suggest a
confident step for the future research on
handedness. The common attitude of people
towards the left-handedness is somewhat
negative that is why the traits of left-handers
are underestimated. It can safely be argued
that a great deal of research is needed to be
done on the relationship of intelligence and
handedness. The accumulated research
findings will go a long way in improving our
understanding about left-handedness and its
consequences. Different ergonomic
interventions should be designed to facilitate
the participation of left-handers in the right-
handers’ dominated world. The future research
should focus upon the relationship that may
exist in different types of intelligence as
proposed by modern theories and
handedness to generate more interesting and
deep insight into the topic. Furthermore, the
present findings point to the significance of
the role of lateralization that must be further
explored in relation to intelligence.
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Saba Ghayas and Adnan Adil, Department of Psychology, University of Sargodha,
Sargodha, Pakistan
Saba Ghayas and Adnan Adil
Received: August 7, 2006
Accepted: December 07, 2006
92
NATIONAL MEMORY COMPETITIONS 2007
At present, the Memory Championship is 5 discipline competitions. This will be conducted at
institutional, district level, state level and national level by the organisers sponsored by the National
Memory Council. The three stages are
Junior – students studying in sixth to eighth standards are eligible to contest
Intermediate – students studying in ninth to twelfth standards, but less than 18 years are
eligible to contest.
Senior – all Indian citizens of 18 years and above are eligible to contest.
Event Description
No Events Description Junior Intermediate Senior
1 Words Generally known words 200 words 300 words 400 words
2 Numbers Random single digit numbers 450 600 750
numbers numbers numbers
3 Binary Binary digits 400 digits 600 digits 800 digits
Numbers
4 Poem A previously unpublished poem 16 lines 24 lines 40 lines
5 Historic Different historic dates 40 60 80
Dates
Memoraisation time – 10 minutes and Recall time – 20 minutes for each event
All competitions at all levels (institution, district, state and national) will be conducted exclusively in
English.
Contestants
The student contestants may be sponsored by the institutions for national level competitions only after
satisfying institutional, district, and state levels.
Institutional District State National level
level level level Junior & Intermediate Senior
Before Before Before Sunday Monday
15.08. 2007 31.08 2007 15. 09. 2007 1.10. 2007 2.10. 2007
Venue: Venue: Venue:
Interested Convener will announce the Achariya Siksha Mandir
schools/colleges venue to the schools/colleges Villianur, Pondicherry- 605 110
Further details if any, kindly feel free to contact:
Dr. G.P. Thakur, President, NMC 2007
Dr. Panch. Ramalingam, Organising Secretary
17, 14th Street, Krishna Nagar, Pondicherry – 605 008, India
Mobile: 94433 52476 E mail: india_nmc@yahoo.co.in
