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How to write introductions and theory sections

Let us show you briefly how to write a paper. You should supplement this reading with more detailed literature, such as the book by Peter Harris ‘Designing and reporting experiments in Psychology’.

Preliminary remarks
A brief word on the order in which you want to arrange different parts of your introduction: many of the main textbooks (including the book by Harris) will encourage you to think of your introduction like a funnel. This means you start very broad and basic and then become more and more specific. This is in principle a good method to follow. However, always remember that it is crucial for the readers to get hooked on early, as they may get bored or worse: stop reading. Therefore, it is always good to start your introduction with a short and precise ‘Why care?’ sentence or paragraph. Basically, you want catch the readers’ interest within the very first sentences.

Relevance of the study
You may want to consider opening your introduction with one of the following four reasons why you consider your study as relevant.
Motive 1: Practical (current) importance (for example: ‘Brexit has shown that…’, ‘Trump’s 2017 election was a sign that…’)
Motive 2: Contribution to an ongoing debate in the literature (for example: ‘There is mixed evidence in the literature about how people decide between choice alternatives depending on their mood.’)
Motive 3: Understand outstanding phenomena (your work has potential to elucidate mechanisms for phenomena or patterns that are extraordinary or outstanding, for example: ‘Humans are remarkable at recognizing faces, however we don’t fully understand how they do it.’)
Motive 4: Understand problematic phenomena (your work potential identifies and addresses mechanisms for phenomena or patterns that are considered problematic, pathological or the source of harm, for example: ‘Humans often deviate from economic rationality and make decisions which incur substantial losses, but we do not fully understand the factors contributing to such disadvantageous decision making.’)

One way to start your paper in an attention-grabbing way is to ask a direct question. This makes the readers curious and the chance that they continue their reading is bigger. Once you have grabbed your readers’ attention, you can limit the scope of your subject and ‘start thinking funnel’!

Literature review (ca. 2-4 pages)
As a next step, you need to write a literature review. It summarizes relevant theories and research findings. The emphasis here lies on the word relevant. Don’t try to impress the readers with tons of literature. They only will be satisfied if you are able to precisely summarize the main studies, results, debates, theories in your field of interest.

It may be hard to decide which studies to include and which to leave out, because of the large body of literature. It may help to ask yourself whether a study is directly relevant for your work or whether it is not. The former should be included, the latter should probably be left out. How is it possible to differentiate between these two? If the findings of the study you want to review directly address your research question, it must be included. If the findings address different questions, they probably can be left out. A good starting point is to include meta-analyses, reviews, as well as the most cited and most recent works that are directly related to your research question. This does NOT mean you should ignore original papers or only look at publications from the past five years! A well-balanced and well-informed literature review often spans many decades, fields and ideas, but recent papers usually give you a good starting point for your own literature search.

Once you have decided on the materials that will form the content of your introduction, the summary you provide must be as precise, short and informative as possible. Here are some advices to reach this goal:
➔ First, make sure you introduce the theoretical framework before you present empirical studies. A good introduction does not simply list research findings, but states the main theoretical framework(s) first and then summarizes the evidence for, or against, a certain theory.
➔ Be aware of the difference between theory and evidence. This is an important distinction. Evidence or research findings only provide a specific pattern in your data, perhaps the mean difference between two groups or the effect of one variable on another. Theory in contrast suggests what patterns are to be expected given certain assumptions about the underlying mechanisms. Put differently, evidence pertains to what you observe in your data, whereas theory pertains to what you would expect, possible interpretations, and how or why you would expect certain observations.
➔ A good introduction not only describes but critically evaluates prior work, which is only possible if you establish the criteria for your evaluation. Your evaluation criteria should be immediately transparent to the readers by delineating your theoretical framework. This provides the boundaries and conditions for your expectations.

If your work aims to directly test a theory or pit theories against each other, you will automatically include a theory section. However, you may have a situation where there is no (or no useful) theory. In this case it can help to shift your focus and delve into other fields. For example, you may be interested in the effect of hormones on risk taking, but you may also find a lot of relevant research if you look at studies investigating the link between personality, impulsivity, or self-control. Some of these differences may be purely semantic and rooted in different fields using different terminology for ostensibly the same thing. But this is not always the case and you may find a lot of useful theory if you cross over to related research topics.

Writing tip: do not use vague words. Instead you should define key terms for your readers. It is better to define too much than too little. The definition can be in parenthesis, between hyphens, commas, or as a single sentence. For example:

The current work investigates prosocial behavior (people acting benevolently for others without a direct or indirect reward).

We study the influence of shame - feeling emotionally uncomfortable after doing something - on consumer behavior.

Risk-taking is an important topic in psychology. Throughout this paper risk-taking is defined as selecting actions with great variability in consequences.

You can improve your writing style by using standard phrases that writers use in academic writing. Check out sentences, which occur again and again in papers that you read (it is okay to use these phrases). Or use sources that provide you with such phrases, such as the Academic Phrasebank.

Introduce your research question (ca. 1-4 paragraphs)
After you have introduced and critically evaluated the current state of research, it is time to present and justify your research question. Explain the readers what is currently not known, debated or unclear, reveal the research gaps in the literature, and thereby create your niche. Where does a current theory (the one that you have reviewed before) fall short? Perhaps a prominent theory has not been tested thoroughly? Do two theories predict opposite patterns in the data? In formulating your research question, you position your research and make explicit why your work matters. Remember: you want to keep the readers interested, so if you can show why your work is essential and/or has implications for (e.g. clinical) applications, you have successfully motivated your work. Therefore it helps to ask yourself and answer the following questions:

1. How does my work contribute to the current literature?
2. How does my work contribute to or build on existing work?
3. What research gap does my work close, how is my work related to other studies?

You can provide a brief overview of your study here, perhaps to show why it differs from previous work (different data? different design? different participants? etc.) or how you are going to close the gap you identified while motivating your work. Important: do not provide details, this is what the method section is for. But if there is anything special about your study, say so, it keeps the readers interested.

State your research hypothesis (ca. 1-2 paragraphs)
Now, you are almost finished writing your introduction. The only thing missing is to succinctly state your research hypothesis. This means, you need to tell the readers what results you expect from your study. It should be clear by now that the theories you mentioned before have to logically lead to the answers to the hypothesis (see 1.2 How to find theories and hypothesis). Previous findings can of course also guide your expectations, but these should ideally be discussed with reference to your theory.

If you want to pitch two theories against each other, here is an example how you could formulate this: ‘According to the ‘mood maintenance hypothesis’, positive affect will result in risk averse behaviour, whereas according to the ‘affect infusion model’ positive affect will result in risk seeking behaviour.’

Make sure you use the appropriate terminology, such as one-sided (directed) hypothesis or two-sided (undirected) hypothesis, and distinguish between the experimental and null hypothesis. If you are unsure what these terms refer to, please consult Peter Harris’ ‘Designing and reporting experiments in Psychology’.

Before you finish, check if everything you mention in your hypothesis appears at least once in the paragraphs before the hypothesis. It is a mistake if your hypothesis introduce new concepts or new theories. In the example above for instance, it would be a mistake if the mood maintenance hypothesis had not been explained before.


Harris, P. (2008). Designing and reporting experiments in psychology. McGraw-Hill Education (UK).


University of Basel