Lab 4: Pseudo-homophones
They sound like words, but they aren’t
In this class you will;
•
learn about pseudohomophones
•
learn to generate your own study in PsychoPy
When people are asked to decide if a letter string is a
word their responses to negative stimuli are slower
when the letter string sounds like a real word
◦ Time to respond ‘no’ is greater for ‘bild’ than for
‘jate’
Rubenstein, Lewis & Reubenstein (1971)
◦ The pseudohomophone effect is evidence that visually
presented words are phonologically encoded.
◦ This process of phonological encoding occurs before
searching the lexicon.
◦ Orthographic checks are made after a phonological
match is found
Martin (1982) pointed out that the two kinds of nonwords used by Rubenstein et al (1971) don’t just
differ phonologically
◦ ‘bild’ sounds like a word and looks like a word
◦ ‘jinf’ doesn’t sound like a word and doesn’t look like
a word
Are people really using phonological information or
are they really using orthographic information?
◦ Martin showed that if the non-homophonic control
words looked as much like a word as the
pseudohomophones, the pseudohomophone effect
disappeared
Underwood et al (1998)
“When readers encountered homophones during a training
phase of the experiment, then a pseudohomophone effect
was observed in a later block of trials which contained no
homophones. A second group of readers encountered no
homophones during either phase of the experiment and
they did not show a pseudohomophone effect.” (Canadian
Journal of Psychology, 1988, 42, pg 24).
People did use phonological evidence when it was
necessary and did not use it when it was not
needed
The usual procedure is:
◦ show one letter string for up to 2s
◦ ask the participant to decide whether it is a word
◦ this is known as the lexical decision task (LDT)
An alternative procedure is the Forced Choice
Reaction Time task:
◦ show two letter strings for up to 2s (a word & a nonword string)
◦ ask participants to decide which letter string is a word
Underwood et al’s (1988) design
◦ A training phase on the lexical decision task
 One group of participants trained with homophones
 One group of participants trained without homophones
◦ A test phase on the lexical decision task
The FCRT adaptation
◦ A training phase on the FCRT task
 One group of participants trained with homophones
 One group of participants trained without homophones
◦ A test phase on the FCRT task
The independent variable – Type of Training
◦ With homophones
◦ Without homophones
The dependent variable
◦ Difference in time to respond to control strings and to
respond to pseudohomophones
Unit of measurement
◦ seconds
According to Underwood et al (1988) the
pseudohomophone effect is found when
participants are trained on homophones.
◦ Training includes homophones
 RT for pseudohomophones > RT for control strings
◦ Training does not include homophones
 RT for pseudohomophones = RT for control strings
Therefore in this experiment
◦ (RT for pseudohomophones - RT for control strings)
for homophone training > (RT for pseudohomophones
- RT for control strings) for no homophone training
Rubenstein et al (1971). Journal of Verbal Learning
and Verbal Behaviour, Vol 10, starting page: 57
Coltheart et al (1977). Attention and Performance,
Volume 6, starting page: 535
Martin (1982) Quarterly Journal of Experimental
Psychology, Section A – Human experimental
Psychology, Vol 34, starting page: 395
Underwood (1988) Canadian Journal of Psychology –
Revue Canadienne de Psychologie, Vol 42, starting
page: 24.