In a lexical decision task (LDT), a participant needs to make a decision about whether combinations of letters are words or not. For example, when you see the word "GIRL", you respond "yes, this is a real English word", but when you see the letters "XLFFE" you respond "No, this is not a real English word".

The task was introduced by Meyer and Schvaneveldt in the 1970s. Their study aimed to understand how long-term memory is organized and how we retrieve information from it. In the original study, Meyer and Schvaneveldt found that people respond more quickly to words that are related in their meaning than to words that are entirely unrelated. This demonstrates that reading a word "activates" related information that facilitates the recognition of other related words.

Today, the task is popular in both psychology and psycholinguistics. There are many variants of lexical decision tasks.

About this implementation

This example is similar to the original Meyer and Svaneveldt Experiment 1, although this is just a demo with a few trials to give you a taste. In the original task, there were 48 associated word pairs. The task is to decide if _both the words are real words (e.g., TEA and COFFEE), or not (e.g., TEA and CFREE). The words chosen in this specific task are created with the fantastic English Lexicon Project.

The demo takes less than 2 minutes to complete.

  • Note, you can show your response times and copy and paste them to a local file for your own data analysis.

Run the demo

Stimulus-response associations

Use the following keys for your response:

  • a if they are both real words

  • l if they are not both words

Data output file

In PsyToolkit, the data output file is simply a textfile. The save line of the PsyToolkit experiment script determines what is being saved in the data output file. Typically, for each experimental trial, you would have exactly one line in your text file, and each number/word on that line gives you the information you need for your data analysis, such as the condition, response speed, and whether an error was made.

Meaning of the columns in the output datafile. You need this information for your data analysis.

Colum Meaning




table row number (this helps you to see all details of the condition)


word 1 (above fix point)


word 2 (below fix point)


condition (related, nonword, or unrelated) (as human readable word)


condition (1=related, 2=nonword, or 3=unrelated)


the response time (ms)


the total time (ms), this is the time the key is pressed down and released


status (1=correct, 2=error, 3=too slow)


If you have a PsyToolkit account, you can upload the zipfile directly to your PsyToolkit account. Watch a video on how to do that. If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this.

Further reading

  • Meyer, D. E., & Schvaneveldt, R. W. (1971). Facilitation in recognizing pairs of words: Evidence of a dependence between retrieval operations. Journal of Experimental Psychology, 90, 227-234.

  • Balota, D. A., Yap, M. J., Cortese, M. J., Hutchison, K. A., Kessler, B., Loftis, B., et al. (2007). The english lexicon project. Behavior Research Methods, 39 (3), 445-459.