What is an Implicit Association Test (IAT)?

What is an Implicit Association Test (IAT)?

10 Min.
By Cristina Ocejo and María López
March 21, 2024

The Implicit Association Test (IAT) is a research tool that uncovers unconscious attitudes and beliefs. In this article, you'll discover what the IAT is and how it reveals hidden aspects of yourself through a quick 10-minute test.

The following video serves as an introduction to Implicit Association Tests.

Introduction to Implicit Association Tests (IAT)

Our experiences, upbringing, and education inevitably shape our biases to some extent. It remains more or less unconscious in our minds, defining our beliefs, influencing our attitudes, and shaping our behavior. For this reason, we associate the color black with elegance and red with passion, or assume that technology is more for boys than girls.

To overcome these biases, we first need to identify those implicit associations. However, asking someone openly about their inherent prejudices or automatic preferences won't provide us with accurate information. Several mechanisms, such as the social desirability bias or other cognitive biases, can affect it.

The Implicit Association Test (IAT) is a research technique that reveals unconscious attitudes and beliefs. In this article, you will learn what the IAT is and how it can uncover hidden aspects of yourself in just 10 minutes test.

The first Implicit Association Test (IAT) was developed in 1998 (Greenwald, A. G., McGhee, D. E., & Schwartz, J. L. K., 1998). Years before, in 1995, social psychologists Mahzarin Banaji and Anthony Greenwald, stated the idea that associations could influence our attitudes and behavior

The IAT was developed to avoid access to consciousness and therefore, to bypass the biases of explicit research techniques (interviews, surveys, or focus groups). 

IAT definition and its neuroscientific basis

An Implicit Association Test (IAT) is a psychological test whose objective is to reveal unconscious attitudes, automatic preferences, and hidden biases by measuring the time that takes an individual to classify concepts.

The Implicit Association Test is based on how our brains process information, a phenomenon explained in part by a dual-process model (eg, Strack & Deutsch, 2004). This model distinguishes between two types of information processing systems (Kahneman, 2011):

  1. The Slow Route: The propositional system, or System 2, involves explicit reasoning processes that are conscious but slow.
  2. The Fast Route: The associative system, also known as System 1. It corresponds to the spread of activation processes and operates quickly but with limited conscious accessibility.

The IAT considers only the fast classifications that result from System 1, the automatic and intuitive one. It ignores the slow classifications that involve System 2, the deliberate and rational one. The central question is the time intervals for responses triggered by System 1 and System 2. 

Timing of System 1 and System 2

When a stimulus event takes place (0ms), our brain starts processing the information. It takes approximately 200-300ms to process and to react to it, for example, by pressing a keyboard key.

A valid response in the IAT should be between 200-300 ms and 650-900 ms:

  • Responses that take less than 200-300 ms are too quick and not valid.
  • Responses that take more than 650-900 ms are likely to involve conscious thinking and not valid either.

IAT reaction time

The exact response time for System 1 varies among individuals and depends on the type of stimuli. Some images or words take longer to process than others. In the IAT, algorithmic methods remove outliers. 

If a concept is categorized into group A faster than group B within the given timeframe, it indicates a stronger subconscious link between the concept and group A in the participant's mind. The quicker the answer, the stronger the association.

What does an IAT look like?

We have developed an Implicit Association Test so you can experience how the test works. You can access it by clicking in the blue pop up that appears in the bottom-left part of this page (you may need refresh your browser). After the test, you can see your own IAT ratings and the average scores from all the tests taken so far. 


The IAT involves rapid categorization of stimuli (words or images) on the screen. The participant must assign them to the correct category or attribute group as fast as possible. Thus, IAT requires two categories and two attribute groups. Categories are the two targets to compare.

Table of Categories Attributes Iat

Experimental protocol

IAT experimental protocol

The experimental protocol includes initial instructions for the participants and 2 classification blocks. Each classification block includes a familiarization and a evaluation task.

Initial instructions

The instructions offers an overview of the IAT and shows the stimuli that will appear in the four stimuli groups: 

In this study, you will complete an Implicit Association Test (IAT) in which you will be asked to sort pictures and words into groups as fast as you can. This study should take about 10 minutes to complete. Next, you will use the 'E' and 'I' computer keys to categorize items into groups as quickly as you can. 

If you make a mistake, a red X will appear on the screen. These are the four groups and the items that belong to each:

  • Good: Stylish, Robust, Fast, Light, Enduring, Sophisticated
  • Bad: Broken, Dirty, Outdated, Slow, Gross, Heavy
  • Category 1: 6 images of Category 1 
  • Category 2: 6 images of Category 2

Familiarization tasks

Familiarization tasks are easy classification tasks with the objective of helping participants to familiarize on how to classify stimuli for the upcoming evaluation tasks. The final IAT report does not include the results of these tasks.

In a familiarization task, you sort stimuli (words or images) that appear one by one in the middle of the screen. The task has two trials.

  • Category trial: Participants see stimuli only from the Categories group (either Category 1 or Category 2). They assign them to the correct category by pressing the letter "E" or "I" according to the instructions in the corner (e.g., press "E" for Category 1 stimuli and press "I" for Category 2 stimuli).
  • Attribute trial: Participants sort stimuli only from the Attributes group (Good or Bad) following the instructions as well (e.g., press "E" for Good ; press "I" for Bad).

Iat Test Familiarization 1

Evaluation tasks 

Evaluation tasks are those that provide us with the IAT results. The evaluation tasks are more challenging than the familiarization ones.

The center of the screen shows stimuli from both the Categories group and the Attributes group.

Participants must sort the stimuli by pressing "E" or "I" according to the instructions in the corners. The instructions now combine categories and attributes (e.g., "press E for Category 1 or Good"; "Press I for Category 2 or Bad"). The instructions are consistent with the ones given in the previous familiarization task (e.g. Category trial: "Press E for Category 1"; "Press I for Category 2"; Attribute trial: "Press E for Good"; "Press I for Bad").

Iat Test 1


The evaluation tasks included in an IAT require classifying stimuli according to instructions that combine categories and attributes. However, the instructions combine categories and attributes differently in each of the two evaluation tasks of the IAT. For instance:

  • Instructions in evaluation task 1: "Press E for Category 1 or Good", and "Press I for Category 2 or Bad".
  • Instructions in evaluation task 2: "Press E for Category 1 or Bad", and "Press I for Category 2 or Good".

IAT experiment 2

Performance is faster when instructions assign a classification key to highly associated category and attribute (e.g., Category 1 + Good) than when they assign a key to less associated category and attribute (e.g., Category 2 + Good). This performance difference implicitly measures differential association of the Category 1 and Category 2 with the Good attribute.

What do the IAT results look like?

A typical IAT score is represented by a graph like the one below. The two bars represent the mean response times for classifying stimuli under the instructions "Category 1 or Good" vs "Category 2 or Good" . The shorter bar indicates a quicker classification and therefore, a stronger association of this attribute with this category. D is the size effect of the difference between the time distributions of each category.

IAT results 3

Bringing the IAT to the next level

Online IAT

Online IAT tests, along with Priming Tests, have emerged as scalable and cost-effective research tools. They enable the collection of unconscious data from hundreds of participants in record time and with significant cost savings.

Participants no longer need to visit a laboratory or wear any physiological sensors. The only requirements are an internet connection and access to a computer, tablet, or smartphone. Completing the task typically requires approximately 10 minutes of focused attention. Check Bitbrain online IAT and Priming Test platform.

Online IAT 2

IAT tests are being increasingly utilized by brands, market research organizations, and other real-world research institutes, including neuromarketing companies. They aim to gain an additional layer of nonconscious information from their audiences to better predict their behavior. Through Implicit Association tests, these organizations predict nonconscious attitudes, aiding in improving brand positioning strategies, selecting brand representatives, analyzing packaging, assessing changes in brand preference when exposed to advertising, and evaluating other marketing elements. Essentially, IAT studies reveal the degree of nonconscious preference for the elements under evaluation

Combining IAT with other implicit and explicit methods

The integration of implicit research methods like IAT, EEG, GSR, BVP, or eye tracking with other explicit research approaches such as surveys, interviews or focus groups, it enables researchers to gain a holistic insight into the participant's thought process. Bitbrain Labs incorporate these implicit techniques in combination with Implicit Bias Tests in online and offline versions.

A research study that use Bitbrain IAT tests

An example in the packaging design field is (Ignacio Gil, 2017). Packaging plays a crucial role in shaping consumers' perceptions of a product, making it essential to understand the most effective design for conveying brand messages. While the use of images on packaging is common, there has been limited scientific exploration of its impact. Studies suggest that images on food packaging can influence consumer perceptions and expectations, traditionally measured through explicit techniques like interviews or questionnaires.

Their study aims to investigate whether implicit consumer responses can be measured using sequential priming techniques, specifically examining the effect of packaging visuals on expectation generation. The findings could offer valuable insights for marketing and design professionals, informing them about how graphic design influences consumer behavior.


The IAT measures unconscious attitudes and beliefs. These tests have been extensively utilized by researchers in social psychology to investigate subconscious biases related to race, gender, sexuality, age, and religion. Even after four decades, these implicit measures continue to be employed, not just to expand the findings of social research, but also to refine and enhance these methodologies. Furthermore, commercial uses like consumer behavior or political preference studies are being tackled and implemented to forecast and pinpoint an implicit preference for a product, brand, celebrity, or political figure. 

In the entry Introduction to Implicit Bias Tests: IAT and Priming implicit test you can continue learning about Implicit Bias techniques and their applications.

Don't forget to take the test!

Remember that you can access it by clicking in the blue pop up that appears in the bottom-left part of this page (you may need refresh your browser)

Other sources

Project Implicit is a collaborative initiative involving scholars from Harvard University, University of Washington, University of Virginia, and Yale University. The project offers a range of Implicit Association Tests (IAT) to collect data on unconscious biases related to discriminatory actions, stereotypes, and prejudices concerning race, ethnicity, religion, gender, sexual orientation, and more. You can participate in a test on their website harvard implicit association tests. In addition to providing your individual IAT results, they will also offer potential interpretations based on research conducted by these universities.

About the author 

María López  (LinkedIn, Twitter) She is the CEO and Co-founder of Bitbrain. PhD in Computer Science at University of Zaragoza and Master in Business Administration at IE Business School.

Cristina Ocejo (LinkedIn, Twitter) She holds a BSc in Psychology from the University of Barcelona and an MSc in Neuromarketing by the Autonomous University of Barcelona.

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Bibliography & References

  • Baumeister R.F., Hutton D.G. (1987) Self-Presentation Theory: Self-Construction and Audience Pleasing. In: Mullen B., Goethals G.R. (eds) Theories of Group Behavior. Springer Series in Social Psychology. Springer, New York, NY.
  • Banakou D, Hanumanthu PD, Slater M (2016) Virtual Embodiment of White People in a Black Virtual Body Leads to a Sustained Reduction in Their Implicit Racial Bias. Front. Hum. Neurosci. 10:601.
  • COVER, C. N. Experimental studies on the role of verbal processes in concept formation and problem solving. Ann. N. Y. Acad. Sci., 1960, 91, 94-107. 
  • Cramer, P. (1966). Mediated priming of associative responses: The effect of time lapse and interpolated activity. Journal of Verbal Learning and Verbal Behavior, 5(2), 163–166.
  • Genschow O, Demanet J, Hersche L, Brass M (2017) An empirical comparison of different implicit measures to predict consumer choice. PLoS ONE 12(8): e0183937.
  • Green, A. R., et al. (2007) Implicit Bias among Physicians and its Prediction of ThrombolysisDecisions for Black and White Patients. Society of General Internal Medicine 2007;22:1231–1238.
  • Greenwald, A. G., Poehlman, T. A., Uhlmann, E. L., & Banaji, M. R. (2009). Understanding and using the Implicit Association Test: III. Meta-analysis of predictive validity. Journal of Personality and Social Psychology, 97(1), 17–41. https://doi.org/10.1037/a0015575
  • Greenwald, et al., (2002). A Unified Theory of Implicit Attitudes, Stereotypes, Self-Esteem, and Self-Concept. Psychological Review. Vol. 109, No. 1, 3–25
  • Greenwald, A.G., & Banaji, M.R. (1995). Implicit social cognition: Attitudes, self-esteem, and stereotypes. Psychological. Review, 102, 4–27.
  • Kahneman, D. (2011). Thinking, fast and slow. New York: Farrar, Straus and Giroux.
  • STORMS, L. H. Backward association: a situational effect. ]. exp. Psychol., 1958, 55, 390-395.
  • Strack, F., & Deutsch, R. (2004). Reflective and impulsive determinants of social behavior. Personality and Social Psychology. Review, 8, 220–247.
  • Everything you need to know about Implicit Reaction Time (IRTs). (2015, September 30). Retrieved March 27, 2020, from http://gemmacalvert.com/everything-you-need-to-know-about-implicit-reaction-time/
  • Tam, T., Hewstone, M., Harwood, J., Voci, A., & Kenworthy, J. (2006). Intergroup Contact and Grandparent–Grandchild Communication: The Effects of Self-Disclosure on Implicit and Explicit Biases Against Older People. Group Processes & Intergroup Relations, 9(3), 413–429.
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