Models of Production and Comprehension [1] Ling4-437

Course outline and objectives  The course presents some of the basic models of language processing as well as some language production models  AIMS: To familiarize students with the METHODOLOGY used to investigate more and less subconscious processes of language perception and production

Aims (contd.)  To discuss (and reconcile) the claims made by opposing camps as to whether language is an autonomous system of cognition or a highly interactive one.

Emphasis on:  Visual and spoken word recognition  Sentence processing concentrating on the effects of CONTEXT on AMBIGUITY RESOLUTION.  Models of word production  Students are encouraged to design and carry out a small scale experiment in the LANGUAGE DEVELOPMENT LAB.

VISUAL WORD RECOGNITION  How a written word is recognized  Initial contact  Lexical selection  Word recognition

Old method  Tachistoscopic identification—  THRESHOLD for each item –  subliminal perception

Reaction time (RT) techniques  i. Naming task : naming latency is measured. ii. Lexical decision task: whether a string of letters is a word or not. Reaction times and error rates are measured. Problem: Speed-error trade-offs. iii. Semantic categorisation task: whether a word belongs to a specific semantic category (semantic field).

However  Absolute reaction time is not significant; only in relation to conditions.  Naming and lexical decision tasks tap different aspects of processing.

METHODS FOR TESTING WORD RECOGNITION  Brain scanning or imaging  Eye movements in reading.  Saccades and fixations.  More time looking at more unpredictable words: highly predictable ones can be altogether skipped.  Going back to avoid or restore mistakes involves regressive eye movements: these are important for finding out how we disambiguate ambiguous material.

PRIMING  It is easier to recognize a word when a semantically related word is presented just before it. SEMANTIC PRIMING. (doctor / nurse)  Priming is best reserved for methodology of investigating what happens when one word precedes another. Facilitation vs. Inhibition.  Stimulus-onset asynchrony (SOA) Prime- target: manipulating the relation between the prime and the target and by varying the SOA we learn a lot about visual word recognition.  A sentence or a whole picture could be the prime.

WHAT MAKES WORD RECOGNITION EASIER OR HARDER  Interfering with identification: we can make a word harder to recognize by degrading its physical appearance (stimulus degradation).  Breaking up the letters or reducing the contrast btw word and background or by rotating the word to an unusual angle.

WHAT MAKES WORD RECOGNITION EASIER OR HARDER (cond.)  Frequency of a word. Frequency counts are important: listing the occurrence per million of a large number of words (Kucera & Francis 1967 based on American English).  There are however differences between dialects (sidewalk vs. pavement) and btw written and spoken word frequency.  Familiarity is based on the idea that there is large variation on the basis of the experiential familiarity with low frequency words

WHAT MAKES WORD RECOGNITION EASIER OR HARDER (cond.)  Age at which you first learn a word (AOA): also with brain damaged patients, words with early AOA are easier to produce.  Cumulative frequency: how often the word is encountered throughout the lifespan.  AOA particularly affects word reading while cumulative frequency affects all tasks. !!! AOA as a result of loss of plasticity

LENGTH EFFECTS How can we measure word-length?  a. the time it takes to say it,  b. number of letters  c. number of syllables

NEIGHBORHOOD EFFECTS  some words have a large number of words that look like them. N-statistic: the number of words that can be created by changing one letter of the target word. N is a measure of neighborhood size (density). (e.g. mine vs. much)  Words with a high N are easy to recognize all else being equal. Clear benefits are only found though for low-frequency words: those with high N are faster to recognize, name and in lexical decision tasks than those with a low N.

WORD VS NON-WORD EFFECTS  words are responded to faster than non-words. Less plausible non-words are rejected faster than more plausible non-words.  Plausible non-words (i.e. ‘possible’ words) are called pseudowords.

REPETITION PRIMING  Once you identify a word, it is easier to identify it the next time you see it.  The technique of facilitating recognition of a word by repeating it, is called repetition priming.  Long-lasting effect (over several hours or even longer).  Repetition priming interacts with frequency. Results more obvious for low frequency words (frequency attenuation).

FORM-BASED (orelse Orthographic) PRIMING  ‘CONTRAST’ primes ‘CONTRACT’; orthographic priming. Very dubious effects (only with primes masked at short SOAs so that the prime is not consciously perceived).