Semantic Priming
Introduction
You should have completed the Lexical Decision activity before doing this activity. You will remember from making lexical decisions that you were asked to decide whether a group of letters was or was not a word. You drew on your knowledge of visual word forms, which has accumulated through years of experience reading actual words. This activity is similar in that you will also be making lexical decisions, but this activity introduces the concept of semantic priming.
Description of Activity
During this activity, you will perform a lexical decision to measure how quickly you can classify stimuli as either words or nonwords. Your job will be to make your decision as quickly and as accurately as possible. For example, you may be presented with a stimulus such as “NURSE,” which is a word, or “SNRUE,” which is a nonword. You will be presented with many words or nonwords during a series of trials. At the beginning of each trial, you will be presented with a fixation “+,” then you will be presented with a stimulus that will stay on the screen until you respond. You will press one key if the stimulus is a nonword and a different key if it is a word. Try to be fast and accurate in making your decisions.
What is a Semantic Prime?
In the lexical decision task, you were asked whether a set of letters formed a real word. You drew primarily on your knowledge of visual word form to do this. Semantics is the study of meaning in language. The words “hospital” and “nurse” mean different things, but their meaning is more closely related than “airport” and “nurse” because (the vast majority of) nurses can be found in hospitals since that is where most do their jobs. A prime is a stimulus that influences the response to a subsequent stimulus. In this activity, if you are presented with “hospital” before “nurse,” then the word “hospital” is the prime because it comes before “nurse.” Even though the words are presented in separate trials, making a lexical decision about “hospital” before “nurse” primes your response to “nurse” so that it is quicker. This happens because “hospital” activates a large set of words that are associated in their meaning, of which “nurse” is one. Your lexical decision to “nurse” after seeing “hospital” will be quicker than if you are first presented with “airport” because “hospital” is more likely to activate the word “nurse,” which has an associated meaning.
Decision Speed and Semantic Priming
In the lexical decision task, words were decided faster than nonwords. That result will replicate in this activity. But this activity introduces semantic primes, with some trials having semantic primes that occur on preceding trials. Your lexical decision speed on trials with semantic primes presented on preceding trials can be compared to other trials where the preceding trial contains an unrelated prime. Decision speed should be slower if the preceding trial contained a prime unrelated in meaning and faster if it contains a semantic prime that is related in meaning. You have accumulated a lifetime of experience by reading and hearing actual words, which allows you to distinguish word forms quicker than non-word forms. But you have also accumulated a lifetime understanding of the meaning of words and their associations with other words. By looking at your results after performing this activity, hopefully you will be convinced of the power of semantic primes in making quicker decisions.