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 non- words 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 non- word 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.