Semantic Priming


You should complete the 'Lexical Decision' Discovery Lab before completing this lab.

Quick, name a vegetable! Did you say 'carrot'? Most people do, but why? Do we eat more carrots than other vegetables? Is it because the 'c' in carrot is near the start of the alphabet? Actually neither explanation is true, the reason most people say 'carrot' is because the word 'vegetable' and the word 'carrot' are closely related, and thinking of 'vegetable' automatically activates the word 'carrot' for most people through spreading activation. The idea that when a word is activated, activation 'spreads' to related words is strongly supported by the results of 'semantic priming experiments' in which the speed of recognizing words is compared in conditions where words are preceded by related words versus conditions where words are preceded by unrelated words. Before we try a semantic priming experiment, consider this illustration of how spreading activation may work:

Here we have a representation for the word 'NURSE'. 'NURSE' has no activation and is not recognized by the word recognition system. Activation needs to reach threshold for recognition to occur.

Next let's assume that the word ‘NURSE’ is presented on a computer screen, seeing the letters 'N-U-R-S-E' would increase activation in the 'NURSE' representation, activation would start approaching the threshold for recognition. Click the 'activate' button to watch activation spread until the NURSE representation reaches threshold

Next activation from NURSE will spread to related words. Click 'spread activation' to see how activation may spread to different words in the lexicon. Notice how activation only spreads to words related to the word 'NURSE' and not to unrelated words such as 'DOG' or 'HOUSE'.

Now suppose you present the word 'DOCTOR' to the person who has just seen 'NURSE' (primed condition) compared to a person who is seeing 'DOCTOR' without having seen a related word first (unprimed condition).... Click the ‘show priming effect' button to see how the word DOCTOR will be recognized more quickly in the 'primed' condition.

Notice how the 'primed' word was recognized more quickly? Now let's see Semantic Priming in action by trying a Semantic Priming experiment.


In semantic priming lexical decision experiments we are interested in the response time to the second stimulus in each stimulus pair. This second stimulus is called the 'target'. We categorize targets based on what type of stimulus the FIRST stimulus (or 'prime') was. Look at the typical results for a semantic priming experiment. The response time difference between the related prime word target condition and the unrelated prime word target condition is referred to as 'the priming effect'. We have grouped all the nonword data together here and note that nonwords following all prime types have slower response times, and have similar response times to each other (there is no priming effect). Results from semantic priming experiments suggest to researchers that word representations are connected by meaning in the mental lexicon.

Review Question

Question: If we were to look at response times for word targets following nonword ‘primes’ and response times for nonword targets following nonword ‘primes’ do you think you would see a difference? Explain your answer.

Answer: There would likely be no difference because a nonword will not activate any words in the lexicon and thus will not cause spreading activation to occur. The priming effect occurs because of spreading activation.