Writing the Intro

First impressions count!  Writing a strong introduction in an essay will help convince the reader that you know what you are talking about.  Many students write very simple introductions, and so a terrific first paragraph will make your writing stand out.  Fortunately, writing a solid introduction is not at all difficult, and can be distilled into a few simple steps.
Think Critically

Watch a movie trailer - such as the trailer for the Facebook-inspired film "The Social Network" (2010) below.  As you watch the trailer, think of the following:

  • What does a good movie trailer accomplish?

  • How much do you know about the movie after watching the trailer?

A good movie trailer does several things:

  • It grabs your attention - you want to know more about the movie

  • It reveals the movie's genre and the main themes that will be explored.  For instance, after watching the trailer for"The Social Network", you know the film is a drama that explores themes of popularity and betrayal

  • It hints at the key dramatic events of the movie - for instance, the invention of Facebook, its incredible rise to success, and the legal battles that follow

A good essay introduction should accomplish the same things as a great movie trailer.  Your introduction should grab the reader's attention, inform them of the main ideas of the essay, and outline the key "events" - the theories and research studies - that will be used to support the arguments.  

Step 1. "Hook" the reader

The "hook" is the first 1-3 sentences of the essay, and is a thought-provoking question, statement, or description of a real life event that captures the reader's attention and convinces them to read further.  In Psychology, we study issues of tremendous importance - why some people develop a mental disorder, for instance, or the role that communication plays in relationships.  In the "hook", you will convince the reader that your essay topic matters - and that it is worth investigating through research - because it can make a difference to people's lives.  

Some ideas for hooks include:

  • Asking a question - Asking a thought-provoking question can be a great way to encourage reflection on the topic - for example, "Are some people born to be depressed?"

  • Making a strong statement - Starting your essay off with a strong statement can get your reader emotionally engaged in the topic.  For example, "Your brain is constantly changing, year by year, day by day, minute by minute".

  • Describing a relevant real-life event - This helps bridge the gap between the Psychology of everyday life and laboratory experiments.  For example, "Ronald Cotton spent years in jail for a crime he didn't commit, after the victim, Jennifer Thompson, testified she was certain that he had raped her.  How could her memory of the crime have been so unreliable?"
Try it Out

Match the Hook (numbers 1-4) with the Essay topic (letters A-D)


1. Although I have spent countless forgotten days at school, I still remember everything about my first day.  All of the new faces, the lessons, even the smells, all still linger in my mind, as if it happened only yesterday.

2.  Why are so many people terrified of rare events, like shark attacks or airplane crashes, but ignore everyday dangers, like artery-clogging fast food or fatal traffic accidents?

3.  During the time it takes you to read this essay, new neural connections are being formed in your brain.

4.  Some people believe in love at first sight, but according to some Psychologists, attraction may be significantly rooted in our sense of smell.

Essay Topics

A.  Heuristics and biases

B.  Flashbulb memory

C. Pheromones

D.  Neuroplasticity

Step 2: Explain Key Terms

Now that you've gotten your reader's attention, the next step is to identify and explain the key terms and concepts that will be used in the rest of your essay.  Write your essay as if you were explaining a topic in Psychology to someone who had never studied it before - and so terms like "neurotransmitter", "brain localization", "schema", "cultural dimension", (and so on) all require detailed explanation.  The key terms and concepts are the building blocks of your essay, but you can only use them successfully once you have explained and defined them well.

For example, if your essay is on the effects of schemas on memory, you first need to explain what a schema is.  By first giving a precise definition (and, even better, an example) of a schema, you can then go on describe and evaluate the role that schemas play in memory.  You might also want to explain terms like "reconstructive memory" and "memory distortion", because these are useful concepts for understanding how memory is influenced by schemas.  Neglecting to explain what a schema is undermines the rest of your essay - how can your readers understand how schemas influence memory if they don't even know what a schema is?

Step 3: State central argument

Your central argument (or thesis statement) is the common thread that will run throughout your essay.  It is the main idea that your essay is based on, and the rest of your essay involves providing reasons, arguments and research evidence in support of your thesis.  Here are some tips to write a good thesis statement:

  • The thesis statement must address the essay topic

  • ​A good thesis statement should be short and simple - just one sentence is ideal

  • A thesis statement should be focused on one main idea

  • A thesis statement makes a concrete claim or argument that will be supported in the rest of the essay

In the examples below, one thesis statement is weak, while the other is strong.  Which do you think is the better thesis statement?

Topic: Flashbulb memory

Thesis A:  Many people have flashbulb memories of important events like JFK's assassination

Thesis B:  Flashbulb memories are exceptionally vivid, but no less reliable than regular memories

Topic: Heuristics and biases

Thesis A:  Heuristics are useful shortcuts in decision making, but their use leads to consistent biases

Thesis B:  There are many heuristics and biases which affect decision making

Topic: Neuroplasticity

Thesis A:  The brain continues to adapt and re-organize itself in response to new situations or environments throughout the lifespan.

Thesis B:  In my opinion, neuroplasticity happens when neurons make new connections with each other.

Step 4: Preview Research 

Now that you have stated what you are going to argue in your essay, the final step in your introduction is to preview how you are going to support your argument.  In Psychology, we support claims by using evidence from research studies.  For instance, if your central argument is that the brain continues to adapt and re-organize itself throughout the lifespan, you need to support this claim with research evidence - such as Maguire's study on taxi drivers. 

In the last sentence or two of your introduction, simply state (and briefly describe) which research studies or theories you will be using to support your thesis.  Doing so gives your reader an idea of what to expect in the rest of your essay.  And then, of course, you will then need to follow the "road map" you have laid out, and actually describe and evaluate those studies in the rest of your essay.

Think Critically

Read the following essay introduction.  Which sentence(s) of the introduction...

  • Is the hook?
  • States the thesis / central argument of the essay?
  • Defines key term(s)?
  • Previews which research studies will be discussed?

"How is information organized and stored in the brain? People don't simply remember things like a video camera does, but are actively involved in processing information based on their cultural background and prior experiences.  Schemas are mental models of people, events and things.  Schemas can help us process new information and facilitate memory retrieval, but they can also influence what and how we remember, leading to false or distorted memories.  In this essay, the role of schemas in memory will be explained and evaluated using research studies by Bradsford & Johnson, who demonstrated how schemas help us encode new information, and Bartlett, who showed how schemas can contribute to memory distortions."


  •  I understand the four parts of a good introduction:  the Hook, definition of Key Terms, Thesis, and Research Preview

  • I can write effective Hooks that capture the reader's attention, such as asking a question, making a strong statement, or describing a relevant real-life event

  • I know the qualities of a good thesis statement: addresses the essay topic, short and simple, one main idea, and makes a concrete claim
Quiz Yourself!

1.  In which order is it recommended to write your introduction in?

(a)  Thesis, hook, key terms, preview research

(b) Thesis, hook, preview research, key terms

(c) Hook, preview research, thesis, key terms

(d) Hook, key terms, thesis, preview research

2.  Which of the following would NOT normally be an example of a hook?

(a) A comparison of two theories

(b) A thought-provoking question

(c) A strong statement

(d) A real-life situation

3.  A good thesis statement should do all the following EXCEPT

(a) Respond to the essay topic

(b) Mention which studies and theories will be discussed

(c) Make a concrete claim

(d0 Express one idea simply and clearly

4.  When defining key terms, you should assume that your reader:

(a) Is a fellow IB Psychology student

(b) Is a knowledgeable IB Psychology teacher or examiner

(c) has never studied Psychology before

(d) is looking for personal advice / self help

1 - D, 2 - A, 3 - B, 4 - C