Testing the Sense of Touch at Home

By Kylie Wolfe

Science doesn’t always happen in a laboratory. It can take place outside or inside, on a hike or in your living room. With the right mindset and method, you can conduct your own experiments and bring science into your home.

Understanding the Scientific Method

The scientific method is used in all scientific disciplines as a means of problem solving. It starts with a simple observation that you can make into a question. If it’s possible to find an answer to the question via an experiment, you can form a hypothesis. A hypothesis is a potential answer to your question and is therefore written as a statement.

To test your hypothesis, you must first design an experiment. Decide what tools you’ll need, who your participants will be, and how it’ll help you reach a conclusion. Be sure to record your data throughout so you can analyze it later.

After your experiment is complete, you may find that your hypothesis was correct. In that case, you can form a conclusion and decide to run additional experiments to learn more. If you find that it was incorrect, you can form a new hypothesis and redesign your approach.

But first, let’s learn about two-point discrimination.

Two-Point Discrimination

The concept of touch is a familiar one. We’re able to recognize temperatures and textures thanks to a variety of sensory receptors near the skin’s surface. They’re responsible for detecting mechanical, thermal, and chemical stimuli, sending signals to the brain and spinal cord.

This process helps us distinguish between different types of stimuli, but tactile sensitivity is dependent on receptor density. Some areas of the body have more receptors than others and are therefore more sensitive.

That said, receptive field size plays a role in a concept known as two-point discrimination, when two points of contact can be detected on the skin’s surface. For this to occur, two receptive fields must be activated, signaling to their respective neurons that there are two points of contact.

Now that you understand some of the science behind our sense of touch, try this experiment inspired by Science News for Students and then come up with your own.

Designing Your Own Experiment

Have you ever noticed how sensitive your fingertips are? They help you feel different textures and tiny objects, and type on a computer. But could they be more sensitive than other parts of your body? You can find out by designing your own experiment.

First, you’ll need a hypothesis. Here’s an example:

Fingertips are more sensitive than upper arms.

Now, how can you determine if your hypothesis is correct? Try a two-point discrimination test. You’ll need a pair of calipers, a blindfold, and some willing participants. Keep in mind, a large sample size will lend itself to more accurate results.

Decide what areas of the body you’re testing, like fingertips and upper arms, and set up a spreadsheet to collect your data.

To begin the experiment, start with the calipers closed, forming one point of contact, and touch them to your participant’s fingertip. Then, remove the calipers, open them slightly, and touch them to your participant’s fingertip again. Repeat this process until they can feel two points of contact instead of one. In millimeters, measure the distance between those two points, and record your data. Follow the same procedure for every participant.

What are your results? What conclusions can you draw?