
			
			
			  Word superiority effect

  
  This experiment is a variant of a study first carried out by Reicher 
  in which he claimed that it was easier to recognize letters within 
  words rather than single letters on their own.

  This seems to counter intuitive because words are more complex 
  stimuli than single letters. The results suggest that top-down 
  processes are used in reading; a word is perceived as a whole unit 
  and does not depend on the identification of individual letters.

  The experiment also demonstrates a use of the technique of 
  `backward masking', where perception of a stimulus is interrupted 
  by the presentation of a `noise' pattern.


			
			
			
			
			
			     
			     Details of procedure

   
   The words were all `high frequency' (very common) 4 letter 
   words, selected from the Thorndike-Lorge list. The `target' letter 
   appeared an equal number of times at each of the 4 possible 
   positions. On `word' trials, either of the response alternatives 
   could, of course, make a word. Single letter trials were matched to 
   the word trials for target letter, position and response alternatives.

   
   There were in fact 4 different exposure times used for 
   presentation of the stimulus before the mask and response 
   alternatives appeared. These were:
		    
		    20,  40,  60,  and 80 milliseconds 

   It is likely that the word superiority effect may only be observed 
   at some `target-mask intervals'. So, see if there is an effect of this 
   interval on the number of errors made as shown in the table of 
   means. Also take a look at response times, but remember that the 
   WSE is about accuracy - not speed.

  
  
  
  There were 28 `word' trials and 28 `single letters trials' at each of 
  these four times, making 224 trials in all. These were presented in 
  random order and the position of the target (correct) letter, either 
  above or below the mask, was random for each trial. The full set 
  of stimuli can be seen in the 'REIWORD.TXT' file.
  
 Procedure:

 Present stimulus word for 75 ms.
 Present a mask
 Pause for 20, 40, 60 or 80 ms.
 Present target letters
 Get response
