Color’s effect on Reaction Times. By: Gustavo Goretkin FLVS Science Fair February 18, 2008. Table of Contents. Introduction 3 Introduction-Purpose 4 Introduction-Purpose 5 Introduction-Purpose 6 Introduction-Preliminary Research 7 Introduction- Two Hypotheses 8
By: Gustavo Goretkin
FLVS Science Fair
February 18, 2008
Primary (Color) – One of three components of light.
RGB – Red, Green, and Blue (three primaries of additive light ) Each primary is represented by a number ranging from 0 to 255. Thus any color is defined by three numbers.
Color distance – the distance between two colors.
User – a human test subject
Flash Application – The computer program sent to the users.
Result – The data generated by a single user.
Trial – A color transitions the Flash Application presents the user with.
Reaction Time- The time between an event’s occurrence and a user reaction to that event.
Conjugate Transitions- two transitions with equal color distances. e.g. red-green and green-red or yellow-red and green-yellow
Visual Basic for Applications (VBA)- A programming language available in the Microsoft office suite to perform automated tasks (Macros).
PHP: Hypertext Processor – A server-side scripting language which can handle data received from a remote computer.
Microsoft Excel- A spreadsheet program used for analyzing and presenting data.
Adobe Flash – A client-side application typically used in making web
These are the colors used throughout the project.
This experiment does not truly test reaction time, though. It tests reaction time plus latency of motor control (pressing a button). Because this latency is expected to be similar throughout the test, the data simply has an offset added and can be accounted for by doing scaling.
This is the initial view of the Flash application.
This display provides trials which have been stored
If the user clicks within 700 ms, then the application will prompt to continue the next trial
This notifies the user that a transition will be occurring soon.
This display provides the status of the main button
This black color will be changing soon.
This is the main button
The button’s color has abruptly changed and the computer awaits a click.
These are the precautions the application takes:
If the user clicks the button before the color change, then there would be a negative reflex time! The user must have accidentally clicked the button so the trial will be discarded and repeated.
If the user takes too long (more than 700 ms) to react to the color change, the application will explain to the user why the error was generated, and will allow the user to repeat the trial. Realistically, human reaction time should be under 700 ms, so if the user did not react in time, it must be because of an abnormality.
This is the submission screen.
When users submit their data, they are given a chance to include their contact information and any comments they’d like the researcher to see. None of these fields are required.
Users may submit up to three times in case they experience issues with their popup blockers.
There are in total 9 color transitions to be tested. These are each tested twice and their times are then averaged. These 18 trials are not presented in any predictable manner so that the user is not able to expect any specific transition.
In addition, there are four initial trials which are not used to gauge the user, but rather to get the user comfortable with the application. This is not made obvious to the users.
This makes for a total of 22 trials.
The time between a trials beginning and a color transition is programmed as:
Random_Interval = (Math.random() * 5000) + 2000;
Where Math.random() represents a value between 0 and 1. The +2000 denotes that the minimum time will be 2 seconds (2000 ms). This is necessary because Math.random() will occasionally be very small and the user would not be able to identify a transition. The random time can be 2-7 seconds.
Thus, each data point will range from 0 to 1, where 1 is the highest and 0 is the lowest reaction time of all nine trials of a single result. Since the purpose is not to compare users to another, but instead to see what affect color has on human reaction times in general, this makes the data more accurate to analyze.
The average of all the raw data (time in ms) was found to be 319 ms. This fits the expected value of 180 ms for reaction time plus mechanical latency (Human Motor Behavior: An Introduction, pg. 70)
In Graph 1 shows the relative averages of all 400 times into 5 groups. These raw data points don’t show a very strong corelation but Excel’s best-fit function reveals that there is a correlation in the data which proves that as color distances increases, reaction time decreases.
Because the first hypothesis states color distance as the only independent variable, it would follow that conjugate colors transitions that have equal color distances trigger similar reaction times. Graphs 3 and 4 counter-prove this. If the order the colors are presented had no affect, then there should be equal percentages of highest color transitions for black-white/white-black, red-green/green-red and green-yellow/yellow-red.
This was not the case. Graph 4 shows that there is an average of 34% difference of time between color transitions of equal distance. Interestingly, though, Graph 2 seems to show similar percentages of quickest times for black-white, red-green and their conjugates, but not for green-yellow/yellow-red.
This leaves Hypothesis one partially proven. Color distance has a significant impact on reaction time, but it is not the only impact. The order the colors are presented also affect the reaction time.
The researcher concluded that this is attributed to the brightness of both of the colors which make users more alert. This rejects Hypothesis two which states that a transition of green-red would be most effective in prompting user reaction. In hindsight, this result appears to make sense if traffic lights are again considered. A green-to-red change does not occur, but rather a green-to-yellow and then a yellow to red change this data proves the effectiveness of the current traffic light system.
Thank you to:
Adobe Systems Incorporated for the trial version of Flash CS3
Matt Keller for his help in designing the computer applications
All participants who responded to the project and provided the researcher with data (Mrs. Flake’s US History and Mrs. Buffington’s AP Biology classes, and friends of mine.)
Human Motor Behavior: An IntroductionJ. A. Scott Kelso, Published 1982 Lawrence Erlbaum Associates available in part at: http://books.google.com/books?id=Z0TUIDbWNhwC&dq=reaction+time+proportional+to+stimulus&source=gbs_summary_s&cad=0)
ImageMAKER Development Inc. (2000). COLORCUBE Literature Retrieved February 8, 2008 fromhttp://www.colorcube.com/articles/articles.htm
Infoplease Article, Pearson Education (2007), Color Psychology Retrieved Feb 14, 2008 from http://www.infoplease.com/spot/colors1.html
Wikipedia, The Free Encyclopedia (February 2008). Mental Chronometry Retrieved February 14, 2008 fromhttp://en.wikipedia.org/wiki/Mental_chronometry
Wikipedia, The Free Encyclopedia (February 2008). Reaction Times Retrieved February 14, 2008 fromhttp://en.wikipedia.org/wiki/Reaction_time