Information Processing Assumptions Measuring the real-time stages General theory –structures –control processes Representation –definition –content vs. code –analog and analyic –types of codes –multiple, isolable, codes and their co-ordination

Assumptions Mental events are a series of real-time events The stimulus undergoes changes in representation There is a limited capacity at various stages

Mental Chronometry Measuring the duration of mental events time is measured in milliseconds 1/1,000 of a second Donder’s subtraction method –Simple RT –Choice RT

Simple RT Sum duration of three basic processes –stimulus encoding –central processing –motor response time

Choice RT Measure the time of an added stage –add a new step onto the simple RT and by subtraction measure the duration of the new step e.g. –choice = discriminate between two stimuli, red and green, circle or square –choice = time to select one of several motor responses

General Theory “Mind” is divided into structures and processes Structures (components of memory) –sensory register –working memory (STM) –LTM Control Processes –voluntary -conscious and unconscious –automatic - unconscious

General Theory All people are assumed to have the same structures Individual, cultural, and developmental differences are assumed to be an aspect of the control processes

Representation Code - must be able to translate between the code and what it stands for –e.g. buying clothes from a catalog, can’t see actual clothing but given several types of representations (picture, written description)

Content vs Code Same info can be represented in different codes. The “best” code depends on the use of the info –e.g. “a picture is worth a thousand words”, but not over the phone –STM preference for acoustic codes

Analog and Analytic Codes Analog e.g. map or picture resembles 2nd order isomorphism detailed to abstract continuous properties similar to perception Analytic e.g. language not resemble arbitrary association needs set of rules for construction and transformations discrete propositions concepts without language equivalents unconscious repres

Types of codes Visual, image, physical, iconic auditory, acoustic, phonetic, echoic semantic, meaning, propositional touch, taste, and smell - all sensory systems produce a code motor code - motor program –not require attention –riding a bike –skilled typist- motor but not visualcode

Multiple Isolable codes and their co-ordination Every time you are exposed to a stimulus - ALL the relevant codes are activated Parallel processing - all codes are activated at the same time, however, there is serial processing within a code Temporal Hiearachy –speed of processing Race Horse Model –simultaneous matching –successive matching

Temporal Hierarchy Posner’s letter matching task –observers are presented with pairs of letters –3 conditions (instructions) for responding same physically identical (A A) same name (A a) same semantic category - vowels or consonants (a e) –results (RT) in milliseconds physical (A A) 549 ms name (A a) 623 ms semantic (A e) 699 ms

Temporal Hierarchy “temporal hierarchy” refers to –physical faster than name faster than semantic Further results support differences in processing speed –In semantic task AA is ms faster than Aa. The ms is the time needed to complete name compared to physical –In physical task saying “no” to Aa is same as Ac - there is no interference of the name (you can answer before name code is finished

Temporal Hierarchy –In name match - slow to say “no” to EF because get interference from the quickly processed physical similarity

Race Horse Model All codes start at the same time but take different amounts of time to finish processing evidence to support this model is based on idea that codes are isolable - sufficiently separate that we can independently manipulate their time course ( influence the duration of one while leaving the others alone).

Simultaneous matching Both letters are presented at the same time manipulate irrelevant physical features to interfere with the physical match, but not influence the name match

Simultaneous matching Cooper and Shepard (1973) –rotate one of the letters –physical RT = 610; name RT = 570 –know name before finish rotation Pachella & Miller (1976) –manipulate physical intensity and relative frequency. –Physical intensity should influence physical code –relative frequency should influence name code

Successive matching Present letters one at a time, remove first before presenting second What is the fate of the stored code of the first letter? Posner -present first letter then vary the delay (ISI) –name matches are unaffected –physical matches show increasing RT with increasing ISI (acoustic recoding)

Successive matching Thorston et al - Visually and acoustically confusing letter pairs –visually confusing - RP, EF –acoustically confusing - TP, BG –plot RT to the “different” response –with increasing time acoustic recoding interferes with the acoustically similar pairs, but helps with the visually similar pairs