C81MPR Practical Methods (Lab 4)

1. C81MPR Practical Methods (Lab 4) Dr. Danielle Ropar & Dr. Jonathan Stirk

2. The Pseudohomophone Effect

3. What is the pseudohomophone effect? • When people are asked to decide if a letter string is a word their responses to non-word strings are slower when the letter string sounds like a real word • Time to respond ‘no’ is greater for ‘bild’ than for ‘jate’ • Rubenstein, Lewis & Rubenstein (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

4. Is the lexicon accessed just by the sound of a word? • Does phonological analysis take place when there is a ‘real’ word present? • Coltheart et al (1977) argued that there may be two access routes to the lexicon: • Phonological code - phonemes • Visual code – graphemes • It may not be necessary to check the ‘sound’ of a letter string if the ‘look’ is well known • Phonological encoding may be strategic

5. The disappearing pseudohomophone effect • Martin (1982) pointed out that the two kinds of non-words used by Rubenstein et al (1971) don’t just differ phonologically • ‘bild’ (pseudohomophone) sounds like a word and looks like a word • ‘jinf’ (control non-word) 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 non-words looked as much like a real word as the pseudohomophones did, then the pseudohomophone effect disappeared

6. The pseudohomophone effect is back again • Underwood et al (1988) “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 used phonological evidence when it was necessary and did not use it when it was not needed.

7. The experimental task • The usual procedure is: • show a 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 (FCRT) task: • show two letter strings for up to 2s • ask participants to decide which letter string is a word

8. Adapting Underwood et al’s procedure • Underwood et al’s (1988) design • A training phase on the LDT • One group of participants trained with homophones • One group of participants trained without homophones • A test phase on the LDT • 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

9. Experimental design • The independent variable – Type of Training • With homophones • Without homophones • Subjects were randomly assigned to either group • The dependent variable • Difference in time to respond to control strings and to respond pseudohomophones • Measures the SIZE of the pseudohomophone effect • Unit of measurement • msecs

10. Theoretical predictions • 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

11. References in brief • Rubenstein et al (1971). Journal of Verbal Learning and Verbal Behaviour, Vol 10, starting page: 645 • Coltheart et al (1977). Attention and Performance, Vol 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. • Note these are NOT in APA format!!!