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B. Introduction

The introduction provides background information, as well as a rationale for the investigation. It is important that this section of the paper clearly sets out what you are going to investigate, and why the investigation is important.

The introduction is an important part of your report.  In addition to describing the study that you are going to replicate, it also helps the reader understand the importance of this study and the theory upon which it is based.  When thinking about writing this section, you should try to explain this as if you are explaining it to someone how has never studied this area of human behaviour before.  Don't make assumptions about what the reader knows about your topic.

The introduction includes the following information:

  • A general introduction to the psychological question under investigation.
  • A description of the theory or model upon which the study is based and an explanation of how the theory or model links to your own experiment.
  • Definition of any terminology necessary for understanding your study.
  • A statement of the aim of your study and an explanation of its relevance. Why is this an important area of investigation?
  • The introduction should end with a statement of the null and research hypotheses specific to your study —that is, a clear prediction of what you expect to find through your investigation. The independent and dependent variables should be fully operationalized in the hypotheses.

The introduction should focus on the theory or model that is investigated and this should include details of the study that is being replicated and how that study investigated the theory or model. It may be helpful for you to describe the study that will be replicated in order to better more clearly explain how the theory you have explained is linked to the study you will do.  However, this is not required.

After explaining the theory on which your study will be based, you should state why you think the theory or model of the original study is important to investigate, which is also explains why the study could be worth replicating. What value does this research have in our understanding of human behaviour? You should finalize your introduction by clearly stating the aim of your research. For example:

  • Aim: to investigate the effects of particular adjectives on the formation of impressions in bilingual high school students.
  • Aim: to investigate the effect of leading questions on the estimation of speed in a car accident in 18-year-old American students with driving experience.

The introduction should then end with a clear statement of the investigation’s null and research hypotheses.  The variables in the hypotheses must be clearly operationalized – and any modifications made to the original study should be justified.

Research and null hypotheses

In experimental research, psychologists first must state what they predict will happen. To do this, we state a null and a research hypothesis.

The null hypothesis states that there will be no effect of the manipulation of the independent variable on the dependent variable -in other words, the null hypothesis states that any difference found is due to chance and not the manipulation of the independent variable. In fact, it is the null hypothesis that is tested as a researcher normally wants this to be refuted.

The research hypothesis predicts how the independent variable is expected to affect the dependent variable. Simply stating that the independent variable will affect the dependent variable is not enough; the actual effect should be clearly predicted.

A well-written hypothesis is clearly operationalized. This means that the IV and DV are stated in a way that is measurable. Simply stating that “Noise will have an effect on learning” is not an operationalized hypothesis. What is meant by “noise?” How are you going to measure “learning?” An operationalized hypothesis for this study might be: Participants who listen to classical music while reading a description of a new school (IV) will be able to recognize more details about the school from a list of statements (DV) than students who read the text in silence.

The aim was to investigate whether there is a higher recall of words using the method of loci in free recall than using no memory technique.

The null hypothesis for this experiment would be There will be no significant difference in the number of details about a school that participants will recognize from a list of statements when listening to classical music or under silent conditions.

Remember that the goal of the research is not to prove the research hypothesis correct, but to refute the null hypothesis. In other words, we want to establish that there actually is a relationship between the IV and the DV, and that any results we have obtained were not just due to chance. When we can statistically establish that the results are not due to chance, the data are significant. When the data are significant, we refute the null hypothesis. When our data are not significant, we retain the null hypothesis. This simply means that the IV did not cause changes in the DV.

Sample Introduction

Cognitive psychologists argue that we are cognitive misers – that is, “humans, valuing their mental processing resources, find different ways to save time and effort when negotiating the social world (Fiske & Harris, p 2).”  One of the ways in which we do this is by using heuristics.  Heuristics can be defined as “judgmental shortcuts that generally get us where we need to go – and quickly – but at the cost of occasionally sending us off course (Gilovich & Savitsky, p 34). ”

Heuristics are part of what Kahnemann refers to as "System 1 thinking."  The Dual Process Model argues that there are two types of thinking - system 1, which is intuitive and based on past experience.  It is a quick response that does not require a lot of conscious effort and often relies on heuristics - or "rules of thumb."  System 2 thinking is deeper, more analytical thinking that requires more effort. Since we are cognitive misers, we try to avoid this level of thinking and often default to system 1 thinking.

One heuristic which helps us to make quick decisions about information is called anchoring.  Anchoring bias is defined as the common human tendency to rely too heavily, or "anchor," on one trait or piece of information when making decisions (Anchoring bias). Anchoring often happens because there is not enough information for the individual to make a decision, so the initial information provided serves as a basis for making further decisions.  This can have serious implications.  For example, Englich & Mussweiler (2001) found that anchoring bias plays a significant role in determining sentencing in courtrooms.  When told that the maximum sentence was 34 months, jurors recommended on average eight months longer in prison than when told that the maximum sentence was 12 months – for the same crime.  In this case, the juror would not have a lot of experience in making these decisions, so the maximum sentence as stated by the judge would then influence the decision for how long the accused should be in prison.

Based on this study, the aim of our investigation is to see if anchoring bias plays a role in mathematical estimation among international high school students. If the presentation of a mathematical problem begins with a low number (1) vs a high number (8), this will influence the estimated value as the first number would serve as an anchor. This study is important because it may play a role in how students are taught maths. Teachers of mathematics often ask students if they think that their answers look reasonable. It is possible that anchoring bias would affect this.

Null hypothesis: There will be no significant difference in the mean responses given by IB higher-level math students when asked to estimate the value of 8!  when the problem is presented in either ascending or descending order.

Research hypothesis: IB higher-level math students will estimate a higher mean value for 8! when the problem is presented in descending order vs. in ascending order.

519 words

Works cited

Anchoring bias in decision-making, Science Daily, retrieved February 28, 2016. Available at: https://www.sciencedaily.com/terms/anchoring.htm

Englich, B., & Mussweiler, T. (2001). Sentencing under uncertainty: Anchoring effects in the courtroom. Journal of Applied Social Psychology, 31, 1535–1551.

Fiske, S.T., & Taylor, S.E. (1991). Social Cognition (2nd ed.). New York: McGraw Hill.

Gilovich, T. & Savitsky, K. (1996). Like goes with like: The role of representativeness in erroneous and pseudoscientific beliefs. Skeptical Inquirer.

Tversky, A.; Kahneman, D. (1974). "Judgment under Uncertainty: Heuristics and Biases". Science 185 (4157): 1124–1131.

Comments on the introduction

Paragraphs 1 - 3: Notice that important terms are defined and the definitions are cited.  Don't just make up a definition, use what is recognized by psychologists as an "official definition" of the terms. The theory is described and its importance is explained using an example. The study to be replicated is described in order to better explain the use of the anchoring bias. Remember, this is actually not required in the IA, but it may help with the development of your explanation.

Paragraph 4: The aim of the study is clearly stated with reference to the population to be studied.  The importance of this study for this population is explained.

The hypotheses are clearly stated with operationalized independent and dependent variables.

How you are assessed 

The following table is the assessment rubric used to award marks for your introduction.

MarksLevel descriptor
0
  • Does not meet the standard below.
1-2
  • The aim of the investigation is stated but its relevance is not identified.
  • The theory or model upon which the investigation is based is identified but the description is incomplete or contains errors.
  • Null and/or research hypotheses are stated, but do not correctly state the independent and/or dependent variables.
3-4
  • The aim of the investigation is stated and its relevance is identified but not explained.
  • The theory or model upon which the investigation is based is described but the link to the investigation is not explained.
  • The independent and dependent variables are correctly stated in the null and/or research hypotheses, but not operationalized.
5-6
  • The aim of the investigation is stated and its relevance is explained.
  • The theory or model upon which the investigation is based is described and the link to the investigation is explained.
  • The independent and dependent variables are stated and operationalized in the null and research hypotheses.

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