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Lexical Decision Making

Lexical Decision Making. Learning Outcomes 1. Carry out a typical piece of laboratory research in psychology. Recognise the use of a within Subjects (repeated measures ) design Identify the Independent & Dependent variables

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Lexical Decision Making

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  1. Lexical Decision Making

  2. Learning Outcomes 1 Carry out a typical piece of laboratory research in psychology. Recognise the use of a within Subjects (repeated measures ) design Identify the Independent & Dependent variables To gain experience of generating your own materials for an experiment To gain experience of partially designing an experiment

  3. Reading - How do we convert a printed word to sound? CAT COMB (silent b) PINT (compare with “mint”, “hint”) FASS MANTINESS KAT SVRTQ

  4. Lexical Decision Deciding whether a string of letters is a real word or not How did you make that decision for the words you just saw? Some non-words could be pronounced (FASS/ MANTINESS) but others could not (SVRTQ). Some non-words sound like real words (KAT)

  5. 2 Theories Reading by Eye: Orthographic (Look-and-Say): Rumelhart and McClelland (1981) Words are read purely based on visual appearance Reading by Ear: Grapheme-Phoneme Conversion (GPC): Rubenstein, Lewis, and Rubenstein (1971) Parts of words are first converted to sound

  6. How to test? If reading is purely by eye you would expect people to be equally fast at deciding that KAT and RUV are non-words If reading is by ear you would expect people to be slower at identifying that KAT is a non-word compared to RUV

  7. Terminology Word = real word (e.g., CAT) Pseudohomophone = non-word that sounds like a real word (e.g., KAT) Legal non-word (e.g., RUV) = non-word that does not sound like a real word (and is a rime)

  8. Lexical Decision Task Based on task by Ellis (1984) Participants are asked to judge whether a string of letters is a real word or not For example ‘Press the right key on keyboard if the item is a word. Press the left key if it is a non-word’

  9. CAT (WORD) Press right key

  10. RUV (LEGAL NON-WORD) Press left key

  11. KAT (PSEUDOHOMOPHONE) Press left key

  12. Independent Variable (IV) and Dependent Variable (DV) IV = Type of letter string Words Pseudohomophones Legal non-words DV = Speed of Response (Average reaction time (RT) for words, pseudohomophones and non-words). NB. The faster the response, the lower the RT

  13. What type of design is this? Repeated measures (or within subjects)

  14. Experimental issues to consider • Within subjects design (the same participant participates in every condition)

  15. What will happen: Design • within Subjects or repeated Measures Design • Pros • bias in groups - solved, since only one group. • don't need many participants to get decent results • cons • contamination between groups (carryover - learning/fatigue) but this may be dealt with by counterbalancing/randomisation • can make the research long for the participant

  16. How to create the lists of words Bleak Sift Meal cake Blean Wift Geal cabe • Bleke • Sipht • Meel • kake

  17. Support for Reading by Eye (Orthographic) Reaction time (RT) for rejecting pseudohomophones (e.g., KAT) should be equally as rapid as for legal non-words (e.g., RUV)

  18. Support for Reading by Ear (Grapheme-Phoneme conversion) Reaction time (RT) for rejecting pseudohomophones (e.g., KAT) should be slower than for legal non-words (e.g., RUV)

  19. What you have to do Construct materials: Word Generation (40 items): 20 words 10 pseudohomonyms 10 legal non-words Instructions to Participants Set up Java program: http://sites.google.com/sites/psychunn Select y1pracs->lexical>run

  20. Get yourselves organised, and run the research • You will ALL need to act as participants (more than once) • You need about 10-12 people per group

  21. Make sure you record the results • You will need to work out the averages of the three conditions for all of your participants (we would like these averages) – have break till 11.45/3.15

  22. Repeat -Lexical decision making there is more than one way to decide on appropriate pronunciation of words, and non-words: CAT, COMB, PINT, FASS, MANTINESS, KAT, SVRTQ Although simple, this task is complex Silent "B" in "comb" Say "pint" but what about "mint" and "hint"? - Can still pronounce some non words, but not others.

  23. Look-and-Say (Orthographic):

  24. Auditory-Conversion (Phonic):

  25. Lexical decision making –How to test? Rubinstein presented a lexical decision task. Decide whether a string of letters was a word or a non word. Some non words were pseudohomophones - kat. If only using visual route reject equally rapidly as other non words geal. If pseudohomophones have an effect, must be translating into the sound. Supports graphic->phonic conversion. .

  26. Lexical decision making –Some support for this idea : Can you understand the following: Wunss uppon a tyme thear wur thrie beirs hoo livd inna hows onn the ej ova phorrest

  27. Grapheme->phoneme? –but reading by shape alone casts some doubt: Aoccdrnig to rscheearch at an Elingsh uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht frist and lsat ltteer is at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae we do not raed ervey lteter by it slef but the wrod as a wlohe. ceehiro

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