Introduction

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 and activation would start approaching the threshold for recognition. Watch the video below to see activation spread until the NURSE representation reaches threshold.

Next, activation from ‘NURSE’ will spread to related words. Watch the video below 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). Watch the video below to see how the word DOCTOR will be recognized more quickly in the ‘primed’ condition.