In this sensory lab, we used bent paper clips to test the density of receptors to detect gentle pressure on three different areas of the skin. The purpose of this lab was to determine which spot of the skin has the highest density of receptors. When the density is high, you can easily sense two touches from the ends of the bent paper clip. When the density is low, it is difficult to sense two touches from the ends of the bent paper clip. To carry out this lab, we did the following:
- Squeeze the clip until the ends are 2cm apart
- Partner’s eyes are closed. Touch the paper clip to the back of the hand 10 times – with 1 end 5 times and with 2 ends 5 times. Mix up the order. After each time, ask whether your partner felt one end or two ends.
- Decrease end distance to 1.5cm apart. Repeat step 2.
- Repeat step 2 for 1cm, 0.5cm, and 0.3cm.
- Repeat steps 2-4 to test the skin on the tip of fingertip and forearm.
Here is the data I collected from my partner:
The shortest distance at which my partner could detect two ends of the clip at least three times on:
Back of hand: 0.3cm
The shortest distance at which I could detect two ends of the clip at least three times on:
Back of hand: 0.3cm
Prior to the lab, I predicted that the fingertip would have the highest density of receptors. After the lab and based on my data, they support the prediction I have made earlier. The fingertip had a higher density than the back of the hand and the forearm because my partner identified most of the touches on the finger with only one mistake, while the touches on the back of the hand and forearm had more mistakes overall.
I think humans have a higher density of receptors for touch in some areas of skin than in other areas because those areas have the ability to sense pressure easily. The touches on the fingertips were easily detected than the other areas due to high density.
The results from the lab does support the prediction I made that the density of receptors in a certain area is different from person to person. We sensed different touch receptors for the back of the hand and forearm, but we had similar results for the fingertips. It was different between my partner and I because every person is different due to a unique genetic makeup. Overall, we both had similar results in indicating the touch receptors in the fingertips, while the forearm and the back of the hand varied.
Factors of indicating touch receptors vary from person to person. No one is exactly the same, therefore sensitivity will vary in a certain area and the amount of receptors indicated. Also, the amount of pressure applied can differ between each trial.
Activities such as playing a guitar, laying bricks, preparing food, or playing video games might affect a person’s sensitivity to touch because the areas are repeatedly used and a person’s sensitivity to touch might decrease. Initially, the fingers and hands are sensitive and will feel the pressure easily, however over the time, they get used to the activities and pressure from them, thus becoming less sensitive.
Overall, this lab was engaging and fun to do. I learned a lot about the density of touch receptors at different parts of the body. Thanks for reading!