Visual Masked Priming

When I'm not studying spoken word recognition, I am often using the visual masked priming paradigm (Forster and Davis, 1984) with lexical decision to explore the processes underlying visual word recognition. In a typical trial of a visual masked priming experiment, participants will see a forward mask consisting of row of hashtags (e.g. for 500 ms), then the prime will display briefly (e.g. 50 ms), then the target will appear (e.g. 500 ms) (Figure 1), and the participants' task is to perform some judgment to the target (e.g. judge whether it is a word). Variants of this paradigm include presenting an intervenor between the prime and the target, which, like the prime, is displayed only briefly (Forster, 2013).

Typically, participants are not consciously aware of the existence of the prime (as in auditory masked priming, some awareness of repetition primes may occur), but they process it anyway, and we know this because their response to the target changes depending on the relationship between the prime and the target. We "mask" the prime by doing four things:

  1. Displaying the prime for only a brief duration (e.g. 50 ms).
  2. Presenting the prime immediately between the forward mask and the target (or an intervenor or backward mask). In this sense, the target serves as a backward mask which further obscures the prime.
  3. Displaying the prime in lowercase font and the target in uppercase font. If the test language does not use different cases, as is the case in Hebrew, then the prime can be presented in a smaller font size than the target to achieve the same effect (Frost et al., 1997).
  4. Presenting all components of a trial in a monospaced font, such as Courier New.
Participants may report that they saw a "flicker" or something "flashing" between the forward mask and the target, but generally the identity of the prime, as well as the prime's existence, remains outside of participants' conscious awareness.

Sample stimuli

You can view sample trials from a visual masked priming study by playing the video files below. In the experiment from which these videos were recorded, the forward masks and targets displayed for 500 ms each and the primes for 50 ms each. However, their precise duration when you play these videos will depend on the properties of your monitor.

In this video, the prime is a repetition prime: the prime is table and the target is TABLE.

In this video, the prime is a form-overlap prime: the prime is blight and the target is BRIGHT.

In this video, the prime is a semantic-associate prime: the prime is rabbit and the target is CARROT.

In this video, the prime is an unrelated prime: the prime is coffee and the target is HAMMER.

If you would like to view sample trials from a visual masked priming study in a more "natural" setting, you can download a demonstration of different priming paradigms which I created by clicking here. The demonstration is programmed to run in DMDX (Forster and Forster, 2003), which is the software we use to present stimuli in masked priming experiments. Please be aware that DMDX will only work on a Windows computer, and so you will need a Windows computer to be able to run this demonstration.

Please be aware that you are downloading a self-executing .zip file (i.e. a .exe file), and so your anti-virus software is likely to ask if you are sure you want to open the file. The file contains nothing malicious: it contains a copy of DMDX, the .rtf file which DMDX reads as instructions for stimulus presentation, and a few other files which DMDX needs to be able to run the demonstration (e.g. the .wav files for the auditory priming demonstrations, a .bat file which launches DMDX when you open the .exe file). Running this file will not install anything on your computer.

Selected references

    Anderson, S. A., and Geary, J. A. (2019). Form priming by discontinuous consonant letter strings in visual masked priming. Proceedings of the 11th International Conference on the Mental Lexicon 1: e060.
    Duñabeitia, J. A., and Carreiras, M. (2011). The relative position priming effect depends on whether letters are vowels or consonants. Journal of Experimental Psychology: Learning, Memory, and Cognition 37: 1143-1163.
    Forster, K. I., and Davis, C. (1984). Repetition priming and frequency attenuation in lexical access. Journal of Experimental Psychology: Learning, Memory, and Cognition 10: 680-698.
    Forster, K. I., and Forster, J. C. (2003). DMDX: A Windows display program with millisecond accuracy. Behavior Research Methods, Instruments, & Computers 35: 116-124.
    Frost, R., Forster, K. I., and Deutsch, A. (1997). What can we learn from the morphology of Hebrew? A masked-priming investigation of morphological representation. Journal of Experimental Psychology: Learning, Memory, and Cognition 23: 829-56.