Developing a new hypothesis is one of the most creative parts of science, a chance for the researcher to use not only his or her reasoning skills, but intuition as well. Just as every painter or sculptor takes a slightly different approach to his art, every scientist has her own own unique approach for developing new ideas. There’s no set formula to follow by rote. There are, however, some key ingredients that are a part of every scientist’s “hypothesis recipe.”
Getting Started:
Inspiration comes from many sources, but there are two general approaches that provide a good starting point for beginners.
1) Observation and induction: A great way to come up with questions is to observe nature. Take a walk in an area relatively free of human influence, and look at what’s going on around you. If you’re patient and observant, you’ll begin to see patterns in what seems at first to be a chaotic jumble of life. Cottonwood trees grow down in the river valleys in Southern Alberta, but not in the coulees or on the ridges. Although every tree is different, they seem to have a common shape, with a bare trunk leading up to a branched and leafy crown. Leaves come out in unison in spring, and fall off in unison in autumn . (Or do they? Don’t some fall a little earlier and others a bit later?)
2) Theory and deduction: A biology textbook or other reliable reference on current theory can be another good way to spark ideas. Think about the predictions that arise from theories that you find interesting. Are there some that have not been tested thoroughly? Could the theory be extended to circumstances where it has not previously been applied? Go a step further and find some original research papers testing the theory. Do the results of some experiments seem to conflict with the theory? Do they raise new questions?
Keep in mind that although these approaches are presented here as alternatives, most scientific inquiries involve a combination of inductive and deductive reasoning.
Ask a question:
Before we can find the right answers about nature, we have to find the right questions (Barnard et al. 1993). Scientific inquiry begins with a question about the world around us. How does a giant redwood manage to get water all the way up to its highest branches and leaves? Why is ice lighter than water? When did life arise on earth? Questions arise out of natural curiosity, but to be useful, must be thought out carefully, to ensure we know exactly what we are asking.
For example Niko Tinbergen, who studied animal behaviour, pointed out that whenever we ask “why” a behaviour occurs, there are four different ways of answering, all equally valid. We can consider the animal’s development or its physiology, and look for the biochemical factors that induce and trigger the behaviour. These types of explanation are often lumped together as proximate (meaning immediate) causes. But we can also look at the animal’s evolutionary history to see if and how it inherits the behaviour from its ancestors, or consider the behaviour’s function — how it aids survival or reproduction. These two factors are referred to as “ultimate” causes. Of course the four types of explanation would produce very different hypotheses, but they are not conflicting, they simply look at different sides of the phenomenon. A focused and clearly shaped question is the first step to a reasonable and testable hypothesis.
Research your topic:
Before developing your own hypothesis, it’s essential to find out what others have already learned on the subject. A thorough review of the relevant scientific literature will help you from repeating what others have already done, and also to avoid blind alleys. You will need to see how your hypothesis fits into general theory, and you will also need to learn what is known about the organism you plan to study, to see how the theory might apply to it. For example, if you were interested in asking about how a particular hormone influences the growth of sweet clover, you might start by reading about what is known about hormones and plant growth in general (you might even need to start with some basic information about plant physiology as background knowledge). You would then want to learn as much as possible about sweet clover (or its close relatives) focusing particularly on physiological processes and growth. A common mistake students make is to begin their search with too narrow a focus, usually looking for information about a particular species. Start by thinking of your question in broader terms, and you will not only find more relevant information, but begin to see how your hypothesis fits into your field of study. For more about useful (and not so useful) sources of information, go here.
Put the pieces together:
Finding information is only half the battle. Digesting what you have learned, sorting relevant information from irrelevant, and finding connections between different studies, are just as important. You should use all the facts at your disposal, assembled with rigorous logic, to build the most reasonable and plausible hypothesis possible, but don’t be afraid to use your creativity and intuition as well.