An Eye for Detail

We explore how fast humans react to seeing recognizable images through crowds. We will test different people to see how fast they can find letters in crowds and use that data to show how the human brain recognizes and finds images.
Naomi Sawyer Naomi Wiebe
Grade 8

Presentation

No video provided

Problem

We are trying to figure out the science behind how someone's age can affect their reaction time to spot something or someone in a group or crowd. We are also trying to figure out if the amount of screen time someone has will affect their reaction time, either slow it down, speed it up, or not change it at all and why.

Method

We are testing 35 people from the ages of 7-50+ at Westview Baptist Church. We will give each person 4 challenges, each increasingly harder, and they have to find the red letter E in a mix of different colours, letters, and fonts. Afterward, we will gather the data and see which age group had the fastest overall reaction time and which age group had the most screen time, and how that affects the data. After, we will look into the science of why certain age groups reacted the way they did, and why or why not screen time also plays a role in it.

Research

A study published in the Journal of Cardiovascular Disease Research observed that screen time did have an impact on reaction times. The study of 147 individuals found that increased screen time reduced reaction time.

Screen time can overloads the sensory system which can induce stress reactions. Acute and chronic stress can produce changes in hormones and brain chemistry. This can reduce problem solving ability and the ability to regulate emotions.

Kids, teens, and adults, love technology and screen time because their brains release dopamine, a reward hormone that keeps them hooked on devices.  “It’s not how long we’re using screens that really matters; it’s how we’re using them and what’s happening in our brains in response,” said the director of the Center on Media and Child Health at Boston Children’s Hospital  (Associate Professor of Pediatrics at Harvard Medical School, and Associate Professor of Social and Behavioral Sciences at the Harvard T.H. Chan School of Public Health.) The brain constanly builds neural connections and gets rid of less used ones, and it is felt screen time contributes negatively in neural connection formation. Many children are said to be “hooked” on electronics, and in fact being on a screen release dopamine and give a “feel good feeling” that can resemble the same kind of dopamine release seen with someone on cocaine.

In terms of age, it is known that the brain anatomy itself changes with age. Older individuals have less grey matter than younger individuals. This is felt to have an impact on the older brain's ability to process information and affects reaction time, as older people need to recruit more neural pathways to complete tasks. Interestingly, the Longevity Study at Stanford University showed that in young adults (aged 18-25), increased screen time could also cause thinning of the cerebral cortex, which is the part of the brain used in problem solving, memory processing and decision making. 

Data

Table 1: Raw Data

 

Age

Screen time

Test 1 

Test 2 

Test 3

Test 4

7-11

          
 

2 hours

0.62s

4.38s

6.42s

43.36s
 

1-2 hours

1.55s

4.92s

34.05s

25.62s
 

1.5 hours

1.34s

3.71s

10.78s

26.41s

12-18

          
 

1 hour

1.15s

1.73s

1.93s

9.28s
 

2 hours

1.61s

3.39s

5.05s

35.77s
 

8 hours

1.68s

3.32s

5.33s

14.28s

19-34

          
 

5 hours

0.65s

2.72s

15.27s

9.87s
 

5 hours

2.08s

5.18s

11.62s

20.14s
 

7 hours

1.01s

5.32s

5.06s

35.98s

35-50

          
 

4 hours

1.09s

4.09s

5.09s

8.13s
 

2 hours

0.79s

6.49s

12.69

57.49s
 

6 hours

1s

1.53s

12.25s

32.52s

50+

          
 

1 hour

1.07s

3.04s

11.79s

7.62s
 

4 ½ hours

1.79s

9.62s

16.78s

53.37s
 

6 hour

1.96s

9.85s

52.66s

42.28s

 

Table 2: Average Screen Time, By Age

Ages

Average screen time

Test 1:

Test 2:

Test 3:

Test 4:

7-11

1.66

1.17

4.33

17.08

31.71

12-18

3.66

1.48

2.81

4.10

19.77

19-34

5.66

1.24

4.40

10.65

21.99

35-50

4

2.88

4.03

10.01

35.96

50+

3.83

1.60

7.50

27.07

34.42

 

Table 3: Total Test Average, By Age

 

 

7-11

12-18

19-34

35-50

50+

Total Test Average

13.57s

4.54s

9.57s

13.22s

17.65

 

Conclusion

Reaction time is important in many areas of life, including in sports and activities with increased risk, such as driving. The Queensland Law and Health Collective stated that the average driver has a reaction time of 1.5-1.7 seconds - or the time to take a deep breath. Reaction time determines if one notices a pedestrian or obstacle in the road. If a driver cannot react that quickly, one could be seriously injured or even worse, killed. Similarly, reaction times are essential in athletics. Professional baseball players make decisions about whether to swing their bats within 500 milliseconds of the pitcher throwing the ball (for context, one blink is 300-400 milliseconds). That could mean the difference between a home run, a strike, or a very bad injury.

The initial hypothesis stated that if the age range of people solving the tests is changed, and the tests get increasingly harder, then the 19-34 year olds will have the most accuracy because they are mostly fully developed but also young, and their brains are active. It was proven to be incorrect. The results of the lab indicate that the 12-18 year olds were the fastest, with an average reaction time of  4.54 seconds. Next were the 19-34 year olds, with an average reaction time of 9.57 seconds, and after them, the 35-50 year olds with an average of 13.22 seconds. Next were the 7-11 year olds, their average being 13.57 seconds, and lastly, the 50+ year olds with an average reaction time of 17.65 seconds.

There were some limitations that may have affected the results of the experiment. When people were timed, the timing may not have been exactly accurate, as the people timing may have paused the timer slightly before or slightly after the person who was being tested had actually found what they needed to find. One other issue is that we weren’t able to test as many people as we wanted to, so we didn’t get that many for each age group, which may have affected the data. This experiment could be modified to test what characteristics make something easy to pop out in a crowd. There could be tests using different descriptions of things or different colours and fonts to see which colour/font/description is the easiest to spot in a crowd.

The test on reaction times that was done by us could be related to real life when someone is trying to catch a criminal. If they have a good reaction time, they can easily spot the criminal in a crowd and it will help with investigation skills. This experiment can also apply to real life because it can help people to know whether or not the amount of screen time that they are having is good for their health and their brain, which can lead to better screen time usage. 

Citations

Acknowledgement

We would like to thank the following individuals for their support in this project: our test participants, Mrs Chan (Arbour Lake School), Ellie Gailer, Suzanne Sawyer and Hanneke Boersma.

We also acknowledge that this research was done on the traditional territories and oral practices of the Treaty 7 Nations, including the Siksikaitsitapi, comprised of the Siksika, the Kainai, the Piikani, and the Amskapi Piikani Nations. We acknowledge the Tsuut’ina Nation, the Îyârhe Nakoda, comprised of the Chiniki, Bearspaw, and Goodstoney Nations, the Métis Nation within Alberta, and all people who make their homes in the Treaty 7 region of southern Alberta.