Phonemes and categorical perception
What is the difference between a sound and a phoneme?
- The phonemes /p/ and /b/ are distinguished by voice onset time (time until vocal chords start vibrating)
- Sounds are in the air
- Phonemes are in the brain
- Analogy - letters and graphemes; Letters are on the page and graphemes are in the brain
I.A.M and its orthographic neighbours
- Word identification time should depend, in part, on its orthographic neighbours.
- When a word is presented, orthographic neighbours become activated, increasing the time necessary to correctly identify the target word.
- This inhibitory effect should be greatest when neighbours are higher in frequency (more common), due to greater resting activation levels.
- Sears et al (2006) - evidence for this inhibitory effect has been hard to come by in English, however, many other languages show it.
What is the word superiority effect?
- The word superiority effect (Tulving et al., 1964), refers to the phenomenon that people have better recognition of letters presented within words as compared to isolated letter and to letters printed within nonword (orthographically illegal, unpronouncable letter array) strings.
- Studies have also found a WSE when letter identification within words is compared to letter identification within pseudowords.
Diagram of the Dual-Route Cascaded Model
What are morphemes?
A morpheme is a meaningful morphological unit of a language that cannot be further divided.
- Root morpheme - e.g. Knit. Does not have a suffix.
- Functional morpheme - e.g. knitted,
There are morphological rules within the use of morphemes.
What is mental lexicon?
Mental lexicon contains mental representations of all word forms (lexemes) that we know.
1) Mental lexicon - pill & pills
2) Morphemes - /pill/ /s/
3) Phonemes - /p/ /s/
Eye movement/Perceptual Span
Types of eye movement
- Saccades: Extremely fast, 'ballistic' (duration ca. 20-50ms). Need to be planned in advance. No visual information available (saccadic suppression).
- Fixation: Stationary periods in between saccades. Mean duration 200-250ms, high variability. Visual information available.
- McConkie and Rayner (1975): Measured the extent of perceptual span using moving window paradigm (15 character window/11 character window).
- Window size was total window size ( 13 = 6 characters to the left of fixation and 6 to the right).FL (full line) =- no mask.
- Performance at 29 is indistinguishable from full line
- Reading is not affected if you take away letters more than 14 characters to the right and more than 3 characters to the left (IN ENGLISH).
- The perceptual span is asymmetric in the direction of reading.