by: Yahan Li ( Yahan.Li.2556@student.uu.se)
PART 1 Errors in the movies
1. The blind people cannot tell other`s height by voice.
In the movie, the blind lady can tell the height of the policeman and the murderer by their voice based on the position of throat. However, I believe this is impossible. First, when the policeman casually questions the lady, he is sitting down on his chair and bending his back, so it is not possible to tell his height because a taller man and a shorter man with this pose can have the same position of their throats. Therefore, the blind lady cannot tell the height when the policeman sits down.
Furthermore, let`s assume that the lady has a chance to heard the policeman`s voice when he is standing up. Different people can have different characteristics of their bodies. For example, some people have longer necks while some have smaller faces. As a result, A 1.76 meter-high man (the murderer) and a 1.70 meter-high man (the policeman) can have the same position of their throats when they stand up.
Blind people can surely tell the position of the source of sound, but it is exaggerated in this movie.
2. The blind people cannot tell other`s physique by echoes, at least in a common room.
The speed of sound is 340m/s, and the hearing ability of human has a limitation: if one wants to distinguish the echo from the original sound, the delay time must be larger than 0.1s. So the transmission distance between the sound source and the obstacle must be longer than 17m (340*0.1 / 2 = 17). However, the room in the police station is quite small, so the blind lady cannot tell the echoes at all.
What`s more, I doubt whether human can use echoes to locate things because other animals who can manage that use ultrasonic waves, such as bats and dolphins. Ultrasound loses little energy when goes across a long distance so it is ideal for detecting objects far away. But human cannot hear ultrasound at all so I think nature didn`t give us the privilege to detect things by sound when human were created.
3. The ability for blind people to keep balance when running fast is misleading.
I participated an experiment of keeping balance when I took a yoga course a year ago. In that test, I was required to close my eyes and stood only with one foot. And my partner counted how many seconds I could keep balance. This experiment is very challenging, my best score was 20s and most of my classmates could only stand for less than 10s. And my teacher told us that the people with excellent sense of balance can stand about 90s. Therefore, it is really hard for me to imagine a blind lady can keep running as fast as she can escape for a long time on the uneven surface of the special path for blind people.
4. The distance sensor (Ultra-cane) cannot tell when the enemy is right in the front of you.
The theatrical climax comes when the leading actress hits the bastard`s head with the help of the distance sensor. The distance sensor can tell you whether something is getting closer by the vibration but you can only know the trend it moves, not the precise location of it. Maybe the blind lady can use the screaming of the bad guy to locate him, but I think it is still not practical because the evil man runs very fast and the sound is not steady because of normal breathe.
PART 2 New findings of being blind:
1. The blind lady can type with a keyboard having sound remind functions. In the movie, when the lady wants to study criminal psychology, she can read Braille and type with that machine very quickly. It is inspiring for me to realize that we can help blind people use the colorful Internet resources by simply providing sound for websites and input devices.
2. The blind lady can use mobile phone to help herself stayed in connection. Her mobile phone also has the function to tell her the instruction she just gave. So once again the lady can follow the mainstream of high-tech society.
To sum up, we, as product designers, can help the disabled people have better life quality by non-excluding design. Just with a small improvement of current designs, we can help them enjoy the excitement and benefit of modern high-tech lifestyle.
Non-excluding Design 