Research question: Does hand dominance have an effect on the speed that a participant completes a visual-spatial task – in this case, mirrored drawing? In other words, would participants complete the mirrored drawing task in a shorter amount of time with their dominant or non-dominant hand?

Hypothesis: There is a significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image. Those who are using their non- dominant hand to perform the visual-spatial mirrored drawing will complete the drawing faster compared to when they are using their dominant hand. Alternative hypothesis: There is a significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image. Those who are using their dominant hand to perform the visual-spatial mirrored drawing will complete the drawing faster compared to when they are using their non- dominant hand. Null hypothesis: There is no significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image.

Background and scientific explanation:

Research conducted by researchers such as Legon, Dionne, Meehan &Staines in 2011 and Spring & Deutsch in 1989 suggest that the left-brain and right brain are not identical in their capabilities. Studies conducted by these three parties indicate that the right hemisphere performs visual spatial task better than the left hemisphere. This is due to the fact that the right hemisphere specializes in visual-spatial task. Springer and Deutsch attributes this to the result of altered sensory gating mechanism due to neural activity differences in the basal ganglia, SMA and M1 during non-dominant hand use (Legon et.al, page 7). In other words, there is increased neural activity in parts of the brain responsible for visual-spatial processing when using the non-dominant hand

Mirror-image tracing requires the participant to use a highlighter to trace the star shown in Figure 1, first with one hand, and then with the other. Because mirror image tracing is a task that predominantly requires hand-eye coordination (i.e. a visual-spatial task), and each half of the brain controls the contralateral side of the body, it is expected that right-handed participants will take longer to complete the task with their right hand (controlled by their left hemisphere) compared to their left hand (controlled by the right hemisphere).

Figure 1: A picture of star that is required to be trace by participants of this experiment

Type of variable Method to control variable Likely impact on the experiment

Independent variable:

Hand used by the participant (i.e. right or left hand)

The participants were instructed first to use their left (their non-dominant hand) followed by their right (their dominant) hand

Participants using their left hand to perform the experiment will be able to trace the star faster and more accurately

Dependent variable:

The speed in which the person is able to complete the task

This experiment will be set up with a mirror attached to the edge of an A4 sheet of paper with blue tack.

The participant will use a provided pen to draw out the star. The participant will be instructed to trace the star in a clockwise fashion from the point labeled X on the image. After I say, “Start”, I will click start on the stopwatch and the participant will start to trace the star. I will observe the participant and after the participant is done tracing the star, I will click stop on the stopwatch. The time taken for the participant to finish tracing the star is then recorded.The unit to measure the time taken for the participant to trace the image is in second. The uncertainty involved in this experiment is quite small as an electronic stopwatch is used. It is ± 0.1 seconds.

The average time taken for the participant to trace the image with his/her left and right hand respectively is calculated. This is done using the formula builder in Excel. See the Sample Calculation for an example. A T-test will be performed after the average time taken to trace the image is calculated. The T-test will be used to determine if there is a significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image.

Type of variable Method to control variable Likely impact on the experiment

Sex of the participant All participants for this A male participant might

experiment will be a female

be able to trace the image quicker compared to a female participant

Age of the participant All participants will be chosen from Year 7 to ensure that at most age difference will be one year

An older participant might be able to trace the image quicker compared to a younger participant

Direction in which the image is trace (i.e. clockwise or counterclockwise)

Participants will be instructed to trace the image in a clockwise direction

Participants tracing the image in a counter clockwise direction might trace the image slower compared to the clockwise direction

The surrounding of the experiment (i.e. the presence of sound etc.)

The experiment will be conducted in a library alcove as it is a quiet environment

A noisy environment might disturb the participant’s concentration and thus the participant may take a longer time to trace the image

Image that the participant has to trace

All participants are given the same image

Participants who get a different image might be able to trace the image quicker.

The sheet of paper that the participant have to trace the image on

All participants are given the same size sheet of A4 paper to trace the image on

Participants who have a larger sheet of paper may be able to trace the image quicker

Pen that the participant uses to trace the image

The same pen is given to all participants of the experiment

The pen that the participant may affect the participant’s speed in tracing the image.

Position of the mirror on the sheet of paper

The same pen sis given to all participants of the experiment

If the mirror is position too close to the image, the participant may struggle with tracing the image and may inadvertently end up looking downward at the image (rather than the mirror)

Distance of participant from the mirror

The participant is instructed to sit with her back towards the chair

A participant sitting close to the mirror may be able to trace the image quicker.

Apparatus

1) 1 x Mirror (15cm by 10cm)

2) 10 x A4 sheets of Paper with Figure 1 (See appendix) printed on it 3) 1 x Black Pen 4) 1 x Electronic Stopwatch (Measures time in second with an accuracy of 3

significant figures) 5) 10 students who are right hand dominant –students should be female, in Year

7 and their dominant hand should be their right 6) Blue tack

Method

1) Ensure that the library is quiet before starting the experiment 2) Find a student willing to take part in the experiment and inform the student of

the nature of the experiment and that data will be calculated. Make sure that the student signs the consent form before proceeding with the experiment

3) Bring the student to one of the alcoves in the library 4) Instruct the student to sit with her back facing the chair5) Instruct the student to trace the image in a clockwise fashion from the point

labeled “X” on the image 6) Instruct the student to place the pen on the starting point and to start whenever

she feels comfortable7) Attach the mirror to the edge of the A4 sheet of paper (with blue tack)

a. Note: The A4 sheet of paper should have the shape in Figure 1 on it. The size of the shape should be the same for all 10 participants

8) Perform a demo for the participant (i.e. trace the image only looking at the mirror and not at my hand or the paper)

9) Instruct the participant to trace the image first with her left hand then her right hand

10) When the student starts to trace the image (i.e. when the pen starts to move from the point labeled X), press start on the stopwatch

11) When the student finish tracing the image (i.e. when the pen has returned to the point labeled X), press stop on the stopwatch

12) Repeat the experiment for 10 students

Ethics:

This experiment involves human participants The participants were informed of the procedure before the experiment

began The steps of the experiment (shown above) were given to the participants They knew that the amount of time that they used to trace the image would

be recorded would be recorded They were given the option to opt out of this experiment if they so wished

Qualitative data:

Qualitative data was collected in this experiment and added value to the experiment. The majority of participants were hesitant and unconfident to trace the image of the

star with their left hand. They also made more mistakes when tracing the image with their left. In contrast, the participants made fewer mistakes when tracing the image with their right hand. 3 of the participants looked down at the image that they were tracing rather than straight at the mirror like they were instructed to and were told to stop doing that and to only look at the mirror.

Table 1:Average amount of time taken to trace the image with right hand in seconds (Uncertainty: ± 0.1 seconds)

Participant Time taken to trace the image with right hand(In seconds ± 0.1 seconds)

1 14.122 12.143 15.494 11.715 16.936 13.447 12.428 14.509 11.9410 16.76

Average amount of time taken to trace the image with right hand in seconds

(Uncertainty ± 0.1 seconds)

13.94

Table 2: Average amount of time taken to trace the image with left hand in seconds (Uncertainty: ± 0.1 seconds)

Participant Time taken to trace the image with left hand(In seconds ± 0.1 seconds)

1 13.542 17.923 16.434 10.345 15.136 14.517 12.848 19.019 16.4210 12.41

Average amount of time taken to trace the image with left hand in seconds

(Uncertainty ± 0.1 seconds)

14.85

Graph 1: Graph showing the average amount of time taken for the participant to trace the image with their left and right hand. The error bars are obtained from the standard

deviation

Table 3: Processed data consisting of the average time taken to trace the image with both left and right hand, the standard deviation and the value of the t-test conducted

Hand used Average amount of time taken to trace the image (In seconds ± 0.1 seconds)

Standard Deviation T-test Value

Right hand 13.94 1.96 T = 1.6186

Left hand 15.13 2.68

Sample calculation:

The average amount of time that it took for the participant(s) to trace the image was

calculated in excel using the formula ∑ of all sample

sample ¿¿¿

Below is the calculation of average amount of time when participant used their right hand to trace the image

14.12+12.14+15.49+11.71+16.93+13.44+12.42+14.5+11.94+16.7610

=13.94

The formula for standard deviation is and was calculated using Excel.

A T-test was used to calculate if there was a significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image. The T-test was calculated automatically in Excel using the formula builder, it is demonstrated below. Note: the T-test perform was a paired T-test as the same 10 participants were used, the 10 participants merely used both their left and right hand to perform the experiment

Conclusion:

The result of the experiment did not support the hypothesis. When the participants used their right hand, the average amount of time taken to trace the image was shorter (13.94 seconds) compared to the average amount of time taken to trace the image with their left hands (15.13 seconds). This is a difference of 1.19 seconds – it is 1.19 seconds slower to use one’s left hand to perform the visual-spatial task (mirror drawing) compared to using one’s right hand. This is also illustrated on the bar chart in which the bar chart in which the bar graph for the average time taken to trace the image with the right hand is shorter than the one demonstrating the average time taken for the participant to trace the image with their right hand. The T-test conducted had a result of 1.61 which indicates that hand dominance does not have a significant difference in the average time that it took the participant(s) to trace the star – in other words, participants, when using their left hand, did not perform the visual-spatial task (mirror drawing) quicker compared to when they used their left hand. Therefore, the results of the experiment do not support the hypothesis of the experiment, in other words, there isn’t a significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image. Those who used their non- dominant hand to perform the visual-spatial mirrored drawing will complete the drawing faster compared to when they are using their dominant hand, thus the alternative hypothesis is to a certain extent true but the results of the experiment do not fully support the alternative hypothesis either as there is no significant difference between the hand used (i.e. dominant or non dominant) and the speed in which the participant completes the tracing of the image, this indicates that the null hypothesis has some validity as well.

Additionally, the uncertainty of the experiment is quite small (± 0.1 seconds). As mentioned at the start, the right hemisphere of the brain specializes in visual spatial task and thus, a person who is right hand dominant, when using their left hand will complete the visual-spatial task in a shorter amount of time. A similar experiment conducted by Serrien and Spapé investigated the effect of hand dominance on mirror drawing supports the hypothesis of this experiment. However, rather than measuring the amount of time it took for the participant to trace the image, Serrien and Spapé measured the neural activity of the participants and found out that while the right hemisphere of the brain is superior to the left with the integration of spatial and temporal information or visuomotor processing, when it comes to high-pressure situation where the participants were supervised, neural processing is spread out across the brain regions. Therefore, the experiment/study conducted by Serrien and Spapé suggests that there should be no significant difference in speed in the tracing of the image; whether the participant uses their left or right hand.

That being said, the standard deviation of the experiment is quite large. When using the right hand, the standard deviation is 1.96 and when using the left hand, the standard deviation is 2.68. This has resulted in error bars that are quite large on Graph 1.

The highest (i.e. longest) recorded time taken to trace the image with the right hand is 16.93 seconds whereas the highest (i.e. longest) recorded time when using the left hand is 19.01 seconds, a difference of 2.08 seconds. Conversely, the lowest (i.e. shortest) time recorded when the participant used their right hand is 11.74 seconds is 12.41 seconds, a difference of 0.64 seconds. The difference in time of 2.08 seconds is more than 3 times of the difference of 0.64 seconds suggesting that a larger sample size and /or the method have to be refined. Moreover, the error bars are quite large suggesting that the results of the experiment are unreliable and further experimentation has to be done. Additionally, although the study conducted by

Serrien and Spapé suggests that the hand used by the participant should have no effect on the time taken for them to trace the image (i.e. complete a mirror drawing – a visual spatial task), the sample size for Serrien and Spapé is only 10 participants whereas the study conducted by Springer and Deutsch that concluded that the non-dominant (i.e. left) hand is more superior to the right when it comes to visual-spatial task was conducted with 606 participants (both male and female) over a 3 month period suggesting that Springer and Deutsch’s result and conclusion is more reliable. To sum it up, more participants are required to participate in the experiment to form a conclusion.

Sherman Ross in the University of Maryland conducted a similar experiment but the results he published in the American Journal of Psychology were conflicting. On one hand, it supports the initial hypothesis of the experiment; the first four trials conducted by Ross suggest that the non-dominant hand is superior to the dominant but with more trials, the difference between the hands became smaller and eventually, the dominant hand demonstrated it’s superiority in mirror-drawing. The data collected by Ross corresponds to mine, participant #1 and participant #5 both demonstrated the superiority of their left hand (their non-dominant hand) as they traced the image in a shorter amount of time with their left hand compared to their right. However, as seen from the average time that it took all 10 participants to trace the image, the right hand demonstrates its superiority over the left hand. Thus, similar to Ross, a larger number of trials should be undertaken. It is important to keep in mind that trials here refer to participant; the same participant should not be used more than twice (once with his/her right hand and once with his/her left hand). Repeating the experiment multiple time with the same participant would be detrimental as a result of learned behavior. This is explored further below in the evaluation section

The qualitative data collected for the experiment adds some value to the experiment in terms of formulating a conclusion. The participants of the experiment felt less confident and more pressured when they were forced to use their left hand and thus, they traced the image of the star slower.

Further investigation has to be done for this experiment. Namely, the use of people who are left hand dominant and observing if they perform better with the left (their dominant) hand or right (their non-dominant) hand. This is important to determine if the right hemisphere of the brain is superior to the left, as those that are left hand dominant will have a more developed left hemisphere. This experiment was carried out with people who are right hand dominant only as there were not enough people who were left hand dominant to carry out the experiment. In addition to that, the accuracy of the participant in completing the mirror drawing should also be investigated. For this experiment, only the speed was considered but some of the participants when tracing the star went out of the line but this was not taken into account.

Evaluation:

With regards to error bars, the amount of participants in this experiment should be increased, as the error bars are quite large. As mentioned above, the sample size is too small and has to be increased to have a more reliable and accurate data set.

The standard deviation for the average time when the left hand is used (2.68) is quite high compared to the average time when the right hand was used to trace the image (1.96) This also suggests that a larger sample size has to be used and/or a more

stringent process should be used to determine if the participants should participate in the experiment. For example, participant #4 who took the shortest time to trace the image with her left hand was an art student and should not have been used for the experiment. The artistic ability of the students was not considered for the students and may have affected the reliability of the experiment.

The range of the independent variable (hand used) is to a certain extent appropriate. Students who were right hand dominant used both their right hand and left hand to trace the image but due to the fact that there were not enough people who were left hand dominant, they were not used for this experiment. Thus, the experiment was only able to determine if people who were right hand dominant performed visual-spatial task better with their non-dominant hand. The way that the dependent variable (the time taken to trace the image) is producing sufficient result, although more scientific and accurate method could have been used in which the neural activity of the left and right hemisphere is measured. However, this would not have been feasible as I had no access to the equipment that Serrien and Spapé did as they conducted their experiment in a university laboratory. The T-test used for this experiment is producing results, indicating that there isn’t a significant difference (between the dominant and non-dominant hand) in time spent on tracing the image.

Source of error ExplanationParticipant would sometimes look at their hand rather than at the mirror

Due to the way that the experiment was set up, participant would occasionally peer down to look at the image that they were tracing rather than looking at the mirror and tracing the image. This would affect the accuracy of the results, as it would not measure the speed in which the participant completed a visual-spatial task but merely the speed in which the participant could trace the image. Therefore, for future experiments, the experiment should be constructed in a fashion similar to Figure 2 (Refer to Appendix), thus the participant are unable to see their hand while tracing the image.

The occurrence of learned behavior (or procedural memory) as a result of the participant having two “trials” in tracing the image as well

Participants being able to witness other participants performing the task first which may also lead to the occurrence of learned behavior

Continued from previous page

The phenomena of learned behavior is present in this experiment. In a mirror drawing task, tracing the image is part of the participant’s procedural memory, one the participant figured out how to draw the image in the mirror, they will have little difficulty the second time. Procedural memory is created through “procedural learning” or repeating a complex activity, which leads to the relevant neural system to work together and automatically produce the activity. In other words, because the participants were first instructed to trace the image with their left hand, then their right hand,

the time taken for them to trace the image with their right hand could be unreliable as they are more familiar and experienced with mirror drawing the second time.

Furthermore, participants were able to witness other participants tracing the image before them which could also lead to learned behavior as they could have potentially learn from the mistakes of other participants. Moreover, this also means that participants were familiar with the image that they were supposed to trace after seeing other people trace it.

Therefore, to eliminate this source of error in future experiment, the first five (or 50% of the total number of participant) should use their dominant hand followed by their non-dominant hand, whereas the other 5 (or the other 50% of the total number of participant) should use their non-dominant hand followed by their dominant hand. Doing this will eliminate any unreliability that may arise from learned behavior and the procedural memory of the participant.

Participants should also be separated from each other so that they would not be able to see the image that they ere suppose to trace until it was their turn to perform the experiment. This would also prevent participants from observing other participants performing the experiment.

Artistic ability of the participant As I later found out, participant # 4 who took the shortest amount of time to trace the image with her left hand was an art student. This leads to an unreliable set of results as it is assumed that art student would perform better in an artistic task such as mirror drawing. Therefore in future experiment, participants who are artistically inclined should be excluded from the experiment.

Difficult to tell when the participant was finished tracing the image

There was a time lag, as the participant would sometimes shout that they were finished before they were actually

finished or only after they were finished because they forgot the instructions given to them. This would thus lead to inaccurate results, as the results would not reflect the time taken for the participant to trace the image. To rectify this error, electronic equipment such as a Wacom Electronic Tablet and Stylus should be used. Doing so would allow for an accurate measurement of time taken by the participant to trace the image, as the electronic stylus would automatically detect when the stylus has been lifted off the tablet. Thus, there is no need to rely on the participant indicating that he/she is done with tracing the image.

Interval between the two times that the participant had to trace the image

Some of the participants took a short break before switching to their dominant (right) hand to trace the image whereas others just proceeded straight away to trace the image. This may have lead to participants who had a short break to perform better with their right hand compared to the participants who proceeded straight away to using their dominant hand to trace the image. To rectify this, participants should be given a timed break of 20 seconds before they have to resume the experiment

Noise of the room The library turned out to be noisier than I expected due to the fact the experiment was conducted at break time. This distracted some of the participants, which may have negatively affected their ability to perform the visual-spatial task (mirror drawing)

This experiment should have been conducted at a time where no one was at the experiment – such as after school.

Mental state of the participant As mentioned in the study conducted by Springer and Deutsch, participants when in a high-pressured and supervised

environment would rely on both hemisphere of the brain and thus slowing down the execution of the task to perform the task. Therefore, in my experiment, participants who were feeling stressed out may perform worse compared to those feeling relaxed as those feeling stressed out would have rely on both hemispheres of their brain to perform the task. To combat this, participants should not be supervised so as to not to stress them out. If an electronic tablet and stylus were used, there would be no need to supervise the experiment, as the data would be automatically collected. On the other hand, the mental state of the participant is difficult to manipulate and telling the participant to “just relax” may not lead to them feeling less pressured.

Works Cited

Deborah J. Serrien, Michiel M. Spapé. "The role of hand dominance and sensorimotor

congruence in voluntary movement." 199. 2 (2009): 195.

Web.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3284250/.

Handedness and Mirror-Drawing. The American Journal of Psychology, 64. 1 (1951):

103-105. JSTOR. Web.http://www.jstor.org/stable/1418601?origin=JSTOR-pdf.

Legon, Wynn, Jennifer K Dionne, Sean K Meehan and W Richard Staines. "Non-

dominant hand movement facilitates the frontal N30 somatosensory evoked

potential." BMC neuroscience, 11. 1 (2010): 112. Print.

Springer, S.P. and G. Deutsch, 1997. Left Brain, Right Brain: Perspective from Cognitive Neuroscience. 5th Edn., W.H. Freeman and Company, New York.