PSY 369 Psycholinguistics Language Comprehension Methods for sentence

PSY 369: Psycholinguistics Language Comprehension: Methods for sentence comprehension

Other Relevant Findings? n Bias towards “well-formed” stimuli n Misidentify words with uncommon spelling patterns n n n BOUT as BOAT misidentify nonwords (e. g. , SALID) as words that are like it (SALAD). Difficulty identifying nonwords with irregular spelling patterns (e. g. , ITPR) more than those with regular spelling patterns (e. g. , PIRT).

Sublexical units n Sublexical units bigger than phonemes and graphemes? n onsets and rimes n n onset: initial consonant or consonant cluster in a word or syllable rime: following vowel and consonants n n if words broken at onset-rime boundary, resulting letter clusters more easily recognized as belonging together than if broken at other points example: FL OST ANK TR vs. FLA ST NK TRO

Adding a bigram level By adding a frequency-sensitive bigram level, we can account for the findings of well-formedness along with the others.

Summing up n Word recognition is based on a feature-detector system n Biased to perceive common or recently occurring features

Studying Word Identification n Generally people ask: what makes word identification easy or difficult? n The assumption: n n Time spent identifying a word can be a measure of difficulty Measures of identification time are usually indirect

Some Identification Time Measures n n Measure how long people take to say a string of letters is (or is not) a word (lexical decision) Measure how long people take to categorise a word (“apple” is a fruit) Measure how long people take to start saying a word (naming or pronunciation time) Measure how long people actually spend looking at a word when READING n n n Line by line reading Word by word reading using eye movement monitoring techniques

Line-by-line A banker is a fellow

Line-by-line who lends you his umbrella

Line-by-line when the sun is shining

Line-by-line but wants it back

Line-by-line the minute it begins to rain.

Line-by-line n Problem: n n Overall reading time for entire sentence or phrase need for more “on-line” measurements n Timing on a smaller scope n See effects at level of word

Word-by-word n RSVP (rapid serial visual presentation)

Word-by-word A

Word-by-word lie

Word-by-word can

Word-by-word travel

Word-by-word halfway

Word-by-word around

Word-by-word the

Word-by-word world

Word-by-word while

Word-by-word the

Word-by-word truth

Word-by-word is

Word-by-word putting

Word-by-word on

Word-by-word its

Word-by-word shoes.

Word-by-word n Moving window

Word-by-word I xxxxx xx xxxxxxxxx xx xxxxx.

Word-by-word x have xxxx xx xxxxxxxxx xx xxxxx.

Word-by-word x xxxx never xxx xx xxxxxxxxx xx xxxxx.

Word-by-word x xxxxx let xx xxxxxxxxx xx xxxxx.

Word-by-word x xxxxx xxx my xxxxxxxxx xx xxxxx.

Word-by-word x xxxxx xx schooling xxxxx xx xxxxx.

Word-by-word x xxxxx xx xxxxx interfere xxxx xx xxxxx.

Word-by-word x xxxxx xx xxxxxxxxx with xx xxxxx.

Word-by-word x xxxxx xx xxxxxxxxx my xxxxx.

Word-by-word x xxxxx xx xxxxxxxxx xx education.

Word-by-word n A couple of methods n n RSVP (rapid serial visual presentation) Moving window Better, more “on-line” But, these measures are also a little bit unnatural (especially RSVP) n e. g. , Don’t allow regressions (looking back)

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye-movements Clothes make the man. Naked people have little or no influence on society.

Eye Movements n Limitations of the visual field n n 130 degrees vertically 180 degrees horizontally Clothes make the man. Naked people have little or no influence on society.

Retinal Sampling

Retinal Sampling

Eye Movements n Within the visual field, eye movements serve two major functions n n Fixation – Position target objects of interest on the fovea Tracking – Keep fixated objects on the fovea despite movements of the object or head

Eye movements n n Fixations Movements n Saccades n Smooth Pursuit

Fixations n n The eye is (almost) still – perceptions are gathered during fixations The most important of eye “movements” n n n 90% of the time the eye is fixated duration: 150 ms - 600 ms Consists of a series of small eye movements (tremor, drift, microsaccades)

Saccades n Saccades are used to move the fovea to the next object/region of interest. n n Connect fixations Duration 10 ms - 120 ms n n Very fast (up to 700 degrees/second) No visual perception during saccades n Vision is suppressed

Saccades

Saccades

Saccades

Saccades

Saccades n Saccades are used to move the fovea to the next object/region of interest. n n Connect fixations Duration 10 ms - 120 ms n n No visual perception during saccades n n n Very fast (up to 700 degrees/second) Vision is suppressed Ballistic movements (pre-programmed) About 150, 000 saccades per day

Smooth Pursuit n n Smooth movement of the eyes for visually tracking a moving object Cannot be performed in static scenes (fixation/saccade behavior instead)

Smooth Pursuit versus Saccades n n n n Jerky No correction Up to 900 degrees/sec Background is not blurred (saccadic suppression) n Smooth pursuit n n Smooth and continuous Constantly corrected by visual feedback Up to 100 degrees/sec Background is blurred

Measuring Eye Movements Purkinje Eye Tracker n n n Laser is aimed at the eye. Laser light is reflected by cornea and lens Pattern of reflected light is received by an array of lightsensitive elements. Very precise Also measures pupil accomodation No head movements

Measuring Eye Movements Video-Based Systems n n Infrared camera directed at eye Image processing hardware determines pupil position and size (and possibly corneal reflection) Good spatial precision (0. 5 degrees) for head-mounted systems Good temporal resolution (up to 500 Hz) possible