PS: Introduction to Psycholinguistics

1. PS: Introduction to Psycholinguistics Winter Term 2005/06 Instructor: Daniel Wiechmann Office hours: Mon 2-3 pm Email: daniel.wiechmann@uni-jena.de Phone: 03641-944534 Web: www.daniel-wiechmann.net

2. Session 3:Visual processing Experience Object Recognition Perceptual organization Buttom-up processing - Visual processing originates from sensory input Sensory input

3. Session 3:Visual processing Prior Experience Object Recognition Perceptual organization Top-down processing Sensory input

4. Session 3:(visual) word recognition Word level Letter level Feature level CAT Assumption: word recognition sequential buttom-up-process

5. Session 3:(visual) word recognition

6. Session 3:(visual) word recognition Word level Letter level top-down effects (word superiority effect) Feature level buttom-up effects Stimulus: COAT

7. Session 3:(visual) word recognition

8. Session 3:(visual) word recognition Summary - word recognition is a combination of buttom-up sensory information and top-down knowledge - word recognition is bi-directional (not sequential) and graded (not discrete) - interactive activation model violates the sequential and discreteness assumptions of a strict information processing model

9. Session 3:(visual) word recognition/ methods • Methods to explore visual recognition • Brain imaging • Examining eye movements • Word identification tasks • Categorisation times • Tachistoscopic identification

10. Session 3:(visual) word recognition/ methods • word identification techniques • Naming task • Subjects name visually presented a words • Naming latency is measured (RT ~ 500ms from onset of stimulus) • Lexical decision task • Subjects decide whether string/sequence is a word or not • RT and error rate is measured

11. Session 3:(visual) word recognition/ methods • Eye movement in reading • e.g. Limbus tracking • Infra red beam is bounced off the eyeball and tracks the the boundary between the iris and the white of the eye (limbus)

12. Session 3:(visual) word recognition/observations • Reading involves rapid ‘jumps’ called saccades • (25 - 60 ms in duration); • length is about eight letters • 10% of all saccades move backwards • Average fixation times range between 200-250 ms • Information retrieval takes place in that interval • Average span: 15 to the right, 3-4 left (for left to right processing)

13. Session 3:(visual) word recognition/observations

14. Session 3:Towards a model of reading • a simple model model • Readers fixate on a word until they have processed it sufficiently • Then eyes move to the next word

15. Session 3:Towards a model of reading • But... • Only 80% content words are fixated • Only 20% of function words are fixated • Rare words are fixated longer than common words • Words that are more predictable in sentence context are fixated for less time • Words that are not fixated tend to be common, short, or predictable • Fixation time of a word is longer when it is preceded by a rare word (spillover effect)

16. Session 3:Towards a model of reading • Problems for the simple model: • It is hard to see how readers could skip words • It takes about 150-200ms to execute an eye-movement program -> readers would waste time waiting for their eyes to move

17. Session 3:Towards a model of reading • Advantages eye-movement recording: • It provides a detailed on-line record of attention-relation processes • Unobstrusive • Disadvantage • Hard to to be sure exactly what processing occurs during each fixation

18. Session 3:Towards a model of reading • E-Z reader model (Reichle 1998) • Readers check frequency (F) of fixated word • Completion of F-check is the signal to initiate eye-movement program

19. Session 3:Towards a model of reading • E-Z reader model (Reichle 1998) • Readers also engage in lexical access (identify orthographic and/or phonological pattern so that semantic information can be retrieved) • Completion of lexical access is signal for shift of attention to the next word

20. Session 3:Towards a model of reading • E-Z reader model (Reichle 1998) cont.: • F-check and lexical access are faster for common words (due to organization of mental lexicon) • F-check and lexical access are completed faster for predictable words

21. Session 3:Towards a model of reading: E-Z reader model Time between successive eye-movements in ms Frequency Effects of word frequency on eye-movements

22. Session 3:Towards a model of reading: E-Z reader model • Parafoveal processing • Readers spend time between completion of lexical access to a word and next saccade in parafoveal precessing of the next word • (this way the model can explain spillover effect)

23. Session 3:(visual) word recognition/observations • fovea ~ most sensitive part of the visual field (2 degrees either side of fixation point • parafovea (extending 5 degrees) • periphery

24. Session 3:Automatic processing • Word recognition is fairly automatic • Reading is mandatory (cf. Stroop effect) • How many mechanisms are involved? • Automatic processes: (fast, parallel, not prone to interference from other tasks, cannot be prevented, facilatatory) • Attentional (controlled) processes: slow, serial, error prone, uses up working memory (WM), often availble to consciousness, can involve inhibition)

25. Session 3:Priming • Priming • Involves the presentation of an item A (prime) before reaction to item B (target) is measured • stimulus-onset asynchrony (SOA) • facilitation vs. Inhibition • Form-based priming • Semantic priming

26. Session 3:Priming • Context effects • Semantic (associative) priming • Lexical decision task • Decision time for target is shorter when prime is semantically related (e.g. DOCTOR - NURSE)

27. Session 3:Priming • Priming from sentential context • “It is important to brush your teeth every single ___!”