73  Lab report writing

Aim: The overarching aim of the lab report is to communicate your research to someone who is not familiar with it. Assume this person is a trained psychologist, but one who is not an expert in the field.

Keep in mind that scientific writing is all about clarity and conciseness. Like the literature search, writing a lab report is an iterative process. You need to go over your lab report again and again, and refine it over time. Also keep in mind (as mentioned in Chapter 25) that every primary research article is essentially a lab report!

Further information on writing lab reports can be found in Beth Morling’s book (“Presenting Results” p. 523ff in 4th edition). The key reference for writing in psychology is of course the APA Publication Manual. There is also a lot of helpful information on the APA Style website.

Lab reports (and articles) have sections to make it easier to find the relevant information. The typical sections of a primary research article (as opposed to, say, a review article) are:

We will consider each of these sections below.

73.1 Title

Aim: The title should summarise the content of the report using no more than 15 words.

Titles often make reference to IVs, DVs and key results, methods, sample characteristics and/or relevant background (e.g., a specific theory).

An example:

Liu, Y., Hou, Y., Quan, H., Zhao, D., Zhao, J., Cao, B., Pang, Y., Chen, H., Lei, X., & Yuan, H. (2023). Mindfulness training improves attention: Evidence from behavioral and event-related potential analyses. Brain Topography, 36(2), 243–254. https://doi.org/10.1007/s10548-023-00938-z

Another example (see Section 25.1):

Avital-Cohen, R., & Tsal, Y. (2016). Top-down processes override bottom-up interference in the flanker task. Psychological Science, 27(5), 651–658. https://doi.org/10.1177/0956797616631737

And a third example (see Chapter 11):

Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S. J., & Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences, 97(8), 4398–4403. https://doi.org/10.1073/pnas.070039597

TipTips
  • Avoid superfluous words (e.g., “An investigation into…”).
  • Avoid abbreviations in the title. Note how the example above says “event-related potential” and not “ERP”.

Here are a few additional examples from recent lectures for you to think about. Choose two examples and analyse their structure. For each title, identify which elements it includes: Does it reference independent variables (IVs), dependent variables (DVs) and key results, methods, sample characteristics, and/or relevant background?

From PSGY1005 Addiction and the Brain:

Franken, I. H. A., van Strien, J. W., Franzek, E. J., & van de Wetering, B. J. (2007). Error-processing deficits in patients with cocaine dependence. Biological Psychology, 75(1), 45–51. https://doi.org/10.1016/j.biopsycho.2006.11.003

Curran, V. H., Brignell, C., Fletcher, S., Middleton, P., & Henry, J. (2002). Cognitive and subjective dose-response effects of acute oral Δ9-tetrahydrocannabinol (THC) in infrequent cannabis users. Psychopharmacology, 164(1), 61–70. https://doi.org/10.1007/s00213-002-1169-0

From PSGY1007 Social Psychology:

Hansen, J., Winzeler, S., & Topolinski, S. (2010). When the death makes you smoke: A terror management perspective on the effectiveness of cigarette on-pack warnings. Journal of Experimental Social Psychology, 46(1), 226–228. https://doi.org/10.1016/j.jesp.2009.09.007

73.2 Abstract

Aim: Provide the reader with a short summary of the study.

The abstract is typically 150-250 words long. It is often what a reader will use to determine whether to read the rest of the study (typically online literature search engines will include the abstract). Therefore, a good abstract matters.

The abstract typically contains:

  • Background: Briefly describes the research context.
  • Rationale/aims: Explains why the research was conducted and what the aims are.
  • Method: Includes key information about the study design, participants, materials, and/or procedures.
  • Results: Highlights the key findings.
  • Conclusions: Explains the significance of the results and their impact on the field.

For example, the Avital-Cohen and Tsal (2016) abstract (175 words):

Distractor interference in the flanker task is commonly viewed as an outcome of unintentional, involuntary processing, a by-product of attention-controlled processing of the target. An important implication of this notion is that the distractors are not subjected to top-down processing of their own. We tested this idea in a modified version of the flanker task, in which letter targets (S or O) were sometimes flanked by ambiguous distractors (a character that could be S or 5 or one that could be O or 0). Distractor interference was dependent on participants’ expectations regarding the category of the distractors (i.e., letters or digits). For example, the O-0 distractor interfered with responding to S when it was perceived as a letter, but not when it was perceived as a digit. Hence, participants applied top-down processing to the peripheral distractors independently of the top-down processing applied to the targets. The fact that to-be-ignored peripheral distractors were processed to such a high level raises questions regarding the fundamental differences between target and distractor processing, and the quality of attentional filtering.

The Maguire et al. (2000) abstract (144 words):

Structural MRIs of the brains of humans with extensive navigation experience, licensed London taxi drivers, were analyzed and compared with those of control subjects who did not drive taxis. The posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects. A more anterior hippocampal region was larger in control subjects than in taxi drivers. Hippocampal volume correlated with the amount of time spent as a taxi driver (positively in the posterior and negatively in the anterior hippocampus). These data are in accordance with the idea that the posterior hippocampus stores a spatial representation of the environment and can expand regionally to accommodate elaboration of this representation in people with a high dependence on navigational skills. It seems that there is a capacity for local plastic change in the structure of the healthy adult human brain in response to environmental demands.

To better guide you through the process of writing an abstract, you will be required to write a so-called structured abstract for your lab report. Structured abstracts have sub-headings.1

Here is the abstract from the Curran et al. (2002) paper cited above as an example (260 words):

Rationale. Although some aspects of memory functions are known to be acutely impaired by Δ9-tetrahydrocannabinol (Δ9-THC; the main active constituent of marijuana), effects on other aspects of memory are not known and the time course of functional impairments is unclear. Objective. The present study aimed to detail the acute and residual cognitive effects of Δ9-THC in infrequent cannabis users. Methods. A balanced, double-blind cross-over design was used to compare the effects of 7.5 mg and 15 mg Δ9-THC with matched placebo in 15 male volunteers. Participants were assessed pre and 1, 2, 4, 6, 8, 24 and 48 h post-drug. Results. Δ9-THC 15 mg impaired performance on two explicit memory tasks at the time of peak plasma concentration (2 h post-drug). At the same time point, performance on an implicit memory task was preserved intact. The higher dose of Δ9-THC resulted in no learning whatsoever occurring over a three-trial selective reminding task at 2 h. Working memory was generally unaffected by Δ9-THC. In several tasks, Δ9-THC increased both speed and error rates, reflecting “riskier” speed-accuracy trade-offs. Subjective effects were also most marked at 2 h but often persisted longer, with participants rating themselves as “stoned” for 8 h. Participants experienced a strong drug effect, liked this effect and, until 4 h, wanted more oral Δ9-THC. No effects of Δ9-THC were found 24 or 48 h following ingestion indicating that the residual effects of oral Δ9-THC are minimal. Conclusions. These data demonstrate that oral Δ9-THC impairs episodic memory and learning in a dose-dependent manner whilst sparing perceptual priming and working memory.

TipTips
  • It is usually easier to write the abstract last.
  • Try not to finish with empty statements such as “the findings will be discussed”.
  • Avoid including references in abstracts. Abstracts should be concise, standalone summaries of a study, meaning readers should not need to look up other articles to understand them. However, if there is a particularly important article, such as in the case of replication studies, it may be appropriate to include a citation in the abstract. For further information on this topic, see this discussion on StackExchange, though note that the example citation provided does not follow APA style.

Here are a couple of additional abstract examples. Choose one example and analyse its structure.

From Franken et al. (2007):

Cocaine abuse and addiction can be characterized by a persisting use of cocaine in the face of adverse consequences. In the present study we focus on one specific element of adverse consequences: the making of errors. The aim of this study was to determine whether cocaine-dependent persons have error-processing deficits as measured using error-related negativity (ERN) and error positivity (Pe). Event-related potentials (ERPs) during an Eriksen flanker task were recorded from cocaine-dependent patients and a control group. Cocaine-addicted patients showed reduced ERN and Pe components as compared to a control group. On the behavioral level, patients showed reduced post-error accuracy improvement. The present findings reveal that cocaine addiction is associated with reduced error processing and impaired behavioral correction of errors after an error is made. These deficits may be associated with a compromised dopamine system. It is argued that these cognitive deficits may contribute to the maintenance of the cocaine addiction.

From Hansen et al. (2010):

One of the principal vehicles for informing tobacco consumers about the risks of smoking is the warning message on each cigarette package. Based on terror management theory, the present study investigates the impact of mortality-salient warnings on cigarette packages compared to warnings with no mortality threat. Results suggest that to the degree that smoking is a source of self-esteem, later attitudes towards smoking become more positive if the warning message is mortality-salient. On the contrary, if the warning is terrifying but not mortality-salient and relates to the source of self-esteem, smoking attitudes become more negative with higher smoking-based self-esteem. Thus, mortality-salient warnings may increase the tendency to favor smoking under certain circumstances. This fatal ironic effect highlights the importance of a risk communication that matches the self-esteem contingencies of the recipients, and it has urgent implications for health care policy.

73.3 Introduction

Aims:

  • Provide the reader with the background knowledge they need to understand your study.
  • Summarise past relevant research in the area. Point out gaps in our knowledge or methodological issues with existing studies.
  • Build a rationale: Explain why you ran the study. For example: What gap in our knowledge does it close? What methodological issue that was present in previous studies does it address? The aim could also be to replicate a previous result.
  • Tell the reader about your hypotheses/expected results in the final paragraph. Sometimes, this final paragraph might also briefly describe essential methodological details or even give the reader a preview of the results.
TipTips
  • Include the most relevant studies. Prioritise recent over older studies.
  • Check that your claims are accurate. Back them up by citing evidence.
  • Avoid quotes. Say things in your own words.
  • Start general and get more specific. Write less about the general aspects and more about the specific ones.
Note

Note that we will have a closer look at introduction sections in Lab 16.

73.4 Method

Aim: There is one key aim of the method section: Replication. That is, after reading your method section, a researcher should be able to repeat your study.

TipTips
  • Ensure that all information relevant for replicating the experiment is included.
  • However, also ensure that irrelevant information is not included.

A method section typically has sub-sections. These sub-sections differ between journals. For the lab report, use the following sub-sections:

  • Design
  • Participants
  • Apparatus and materials
  • Procedure
  • Data analysis

73.4.1 Design

The design section should include the following information:

  • A formal description of the type of design being used (using psychological design language). E.g., design type might be a within-subjects or between-subjects design.
  • Description of the IVs and DVs where appropriate (remember that correlational designs have no IVs because variables are not manipulated).
  • Where applicable, design controls (e.g., counterbalancing).
  • Assignment of participants to conditions.

73.4.2 Participants

Include the following information:

Number of participants and demographics

  • Total number of participants.
  • Age (mean, standard deviation, and minimum/maximum age).
  • Gender distribution.
  • If relevant, include ethnicity, socioeconomic status, education level, and other demographic factors.

Inclusion and exclusion criteria

  • Explain the criteria used to select participants.
  • Mention any specific characteristics required for inclusion (e.g., language proficiency).
  • List reasons why certain individuals were excluded. Report the number of excluded participants.

Recruitment process

  • Explain how participants were recruited (e.g., advertisements, university subject pools, online platforms).
  • If applicable, note whether they were compensated (e.g., course credit, monetary rewards).

Ethics

  • State if the study was approved by an Ethics Committee.
  • Mention if participants gave informed consent.
TipTip
  • In my view, it is a good idea to recalculate descriptive statistics after excluding participants if the participant exclusion means that these statistics have changed meaningfully.

73.4.3 Apparatus and materials

This section describes the apparatus and materials used in testing the participants. It typically includes the following elements:

Apparatus

If the study involved specialised equipment, describe:

  • Hardware: Computers, screens, response boxes, eye trackers, etc.
  • Software: Any software or digital tools used (e.g., PsychoPy, Qualtrics for surveys) and their specific versions. Where appicable, make sure to cite the software (e.g., PsychoPy).
  • Other equipment: E.g., soundproof rooms, specific lighting conditions, use of a chin rest, or any other physical setup that could impact results.

Materials

If the study involved questionnaires, surveys, or experimental stimuli, include:

  • Questionnaires and scales
    • Names of standardised tests (e.g., Beck Depression Inventory, Big Five Personality Test) and reference.
    • Reliability and validity information, if applicable.
    • Example items.
  • Stimuli
    • Type of stimuli used (e.g., letters, words, images, audio clips, videos) and their characteristics (e.g., sizes and colours).
    • Source of stimuli (e.g., pre-existing databases like the International Affective Picture System, self-created).
    • Presentation method (e.g., on a screen, printed cards).
TipTips
  • It is often easier to give some visual examples of stimuli within a figure rather than describing them verbally.
  • When multiple experimental tasks are reported, it is often preferable to group the method section by task. We will share an example for this with you in our lab report template.

73.4.4 Procedure

This section describes how the design was implemented.

  • Detail what participants were told before the study (general instructions, task explanations).
  • Describe what participants did in the study, step by step.
    • If applicable, explain different conditions or groups.
    • Explain how participants were instructed to complete tasks or questionnaires. Any emphasis within instructions about how to respond should be included. E.g.: “Participants were asked to respond as quickly and accurately as possible.”
    • Specify if participants were given practice trials before the actual experiment.
    • Mention important timings (especially important in many cognitive tasks).
    • Indicate how long each task or session lasted. If participants had rest periods or multiple sessions, mention their timing and purpose.
TipTip
  • Long instructions can be put into an appendix, but must then be referred to in the text. E.g.: “For a full transcript of the instructions, see Appendix 1.” Shorter instructions can be included in the main procedure section.

73.4.5 Data analysis

This section describes how the collected data were processed and analysed.

Data preparation

  • Handling of missing data: Describe how missing data were treated.
  • Data cleaning procedures: Mention if any data were excluded and the criteria for exclusion (e.g., outliers, incomplete responses).
  • Scoring and variable computation: Explain how scores were computed (e.g., interference effects).

Statistical tests used

  • List the main statistical tests used to test hypotheses (e.g., t-tests, ANOVA, regression).
  • If multiple comparisons were made, mention any corrections applied (e.g., Bonferroni correction).
  • Assumption checks
    • State whether normality or other statistical assumptions were tested.
    • Mention transformations or adjustments made if assumptions were violated.

Software

  • Specify the statistical software used (e.g., SPSS, jamovi or R).

Significance level and effect sizes

  • Indicate the alpha level (e.g., p < .05).
  • Explain what effect sizes will be reported (e.g., Cohen’s d, dZ or r).
TipTip
  • If any data will not be analysed, explain this in the data analysis section. A typical example would be two students working together on a final-year project. All their participants complete an experimental task and two questionnaires, A and B. One student includes questionnaire A in their analysis, while the other includes questionnaire B. The method section must describe all tasks and questionnaires that participants completed, regardless of whether they are included in the respective analysis. In the data analysis section, students should then explain their specific focus and why the other questionnaire will not be analysed.
  • A research-based example would be a researcher planning to write multiple articles based on a particular dataset. In the data analysis section, they should explain that the remaining data will be analysed in a separate publication.

73.5 Results

Aim: Present the study’s findings of the study clearly, concisely and objectively.

The results section typically has these sub-sections (but usually without explicit sub-headings):

Descriptive statistics

  • Provide a summary of the data (e.g., means, standard deviations, frequencies, percentages).
  • Use tables or figures if they improve clarity (follow APA guidelines for formatting).

Inferential statistics

  • Present the results of statistical tests used to test hypotheses.
  • Follow APA reporting guidelines (see Chapter 66 and Chapter 68).

Exploratory or additional analyses (if applicable)

  • If any unplanned or control analyses were performed, report them here.
  • Example: You might wonder if the inclusion of non-native speakers might have influenced results. You could run a control analysis to check if excluding non-native speakers changes the results.
    • Don’t speculate in your discussion section about things you could have checked in a control analysis.
TipTips
  • Always report results for all analyses, no matter if they were significant or not significant.
  • Use past tense (since the study has been conducted).
  • Avoid unnecessary repetition.

73.6 Discussion

Aim: The discussion section of a psychological research paper interprets and explains the study’s findings.

In the discussion, you link your findings to existing research, and describe theoretical implications, limitations and future directions. It’s where you make sense of the results rather than just reporting them.

Key components of the discussion section:

Summary of key findings

  • Briefly restate the main results without statistics.
  • Clearly connect findings to research questions or hypotheses.

“In accordance with our hypothesis, the present study found that participants in the mindfulness condition reported significantly lower stress levels than those in the control group. However, contrary to our predictions, no significant differences were observed in anxiety scores.”2

Interpretation of results

  • Explain why the findings occurred, referencing theories or past research.
  • Address whether the results support or contradict previous studies.

“These results align with prior research suggesting that mindfulness interventions reduce stress (Smith, 2020), but contradict findings by Berger et al. (2018), who found no significant effect on stress levels following a brief mindfulness intervention programme.”

Theoretical and/or practical implications

  • Discuss how the findings contribute to psychological theories.
  • Where applicable, consider real-world applications (e.g., therapy, education, policy changes).

“These findings suggest that brief mindfulness interventions could be a cost-effective strategy for reducing workplace stress.”

Limitations of the study

  • Acknowledge shortcomings of the study.
  • Be critical, but not overcritical of your own study.

“One limitation of this study is the reliance on self-reported stress levels, which may be subject to social desirability bias.”

Future research directions

  • Suggest how future studies could improve or expand on the findings.

“Future research should explore the long-term effects of mindfulness interventions using physiological stress markers such as cortisol levels.”

Conclusion

  • Conclude with a short paragraph summarising the main findings and implications.
TipTips
  • Think hard about you’re going to write. Then think again. And again. This section is where you can shine. Show us that you did think about what it all means and how to interpret it.
  • Use past tense for results and present tense for interpretations.
Note

Note that we will have a closer look at introduction sections in Lab 17.

73.7 References

Make sure to follow APA style. This is far from trivial.

TipTip
  • As this is far from trivial, use a reference management software (e.g., Zotero or EndNote).

73.8 Appendices

Include your SPSS output.

  1. Note that lab reports you write in your second year might not require a structured abstract.↩︎

  2. Note that all the examples are just brief illustrations. An actual discussion section would need to be more in depth!↩︎