•    Encoding: Converting information into a useable form

•    Storage: Holding this information in memory for later use

•    Retrieval: Taking memories out of storage

II. Structures

    A. Sensory Memory

    Memory based on a particular sensory modality

    Briefest memory stores last for only a fraction of a second...An integral part of the process of perceiving

     Iconic memory (for vision) and echoic memory (for audition) represent the earliest stages of sensory memory

         Similar systems probably exist for the other senses

**What is the capacity and duration of iconic memory?                                              

For lecture:

Trans A

Trans B

  

   Sperling (1960)—whole-report technique—presented participants (Ps) with a stimulus comprising three rows of four letters.  When shown these for 50 msec, followed by a blank white field, Ss were able to report only about four or five of the twelve letters. 

    Were these the only letters that had been seen, or could P have seen them all, but forgotten some of them in the time it takes to report five letters?  

        Partial-report technique—P cued to report only one line of letters

          

    How should Sperling’s results be interpreted?   

    Sperling described iconic memory  as precategorical

    Once the item is scanned, need to rehearse or the information will be lost.

    Auditory confusion errors--tendency for errors to be similar to the correct item in sound rather than in visual characteristics.  Suggests speech-based coding of visually presented letters. 

**What is the capacity and duration of echoic memory?

    Partial report for echoic memory--Darwin, Turvey, and Crowder (1972)

  Three lists of three digits.  Played 3 lists simultaneously from 3 different locations.  

           

    Clear advantage for partial report up until approx. 4 seconds

    Capacity is not as large as with iconic memory, but echoic memory lasts longer 

    Echoic memory appeared similar to iconic memory with just two minor differences:
(1) echoic memory lasts longer (approx. 4s compared to approx. 1 s for iconic), but
(2) does not preserve as much information (about 4 or 5 items compared to 8 or 9 for iconic)  

 

    B. Working (short-term) Memory

Capacity of Short-Term Memory
    George Miller (1956)—“The magic number seven, plus or minus two 

       Two main findings: 

       (1) Ss are unable to identify a set of items that vary along only one dimension if there are more than a few items

 
 

    (2) Chunking--Increase capacity of short-term memory by grouping individual units of information into meaningful units.

 

Duration of the Trace in Short-Term Memory 

    Brown-Peterson Paradigm
    Purpose—determine rate at which information decays in STS
    Method—experimenter reads a consonant trigram and then 3-digit number.  S had to count backward by 3 from the 3-digit number for a certain amount of time then had to recall the trigram. 

 

     Results-- rapid rate of forgetting after as little as 18 s  

    Forgetting in short-term memory--decay or interference?

Important question--Is short-term memory (STM) only a temporary storage place or does it also have some processing capabilities?

Baddeley's (1986) dual-task technique--Ss were required to remember number sequences ranging from zero to eight digits in length, while at the same time performing a reasoning test.

    Assumption: Performing a concurrent STM task should lead to a dramatic impairment in performance IF STM is a unitary system .

    Effect of concurrent memory load on the speed and accuracy with which Ss performed the syntactic reasoning test:

Results: (1) reasoning time increases clearly and systematically with concurrent memory load (2) The effect, however, is not catastrophic  

If STS is a unitary system, a concurrent load of eight digits should cause reasoning performance to break down completely.  It does not.

Earlier concept of a unitary STS is challenged and replaced by a multi-component working memory model. 

The limits of digit span may be set by one of a number of subsystems, leaving other components of working memory relatively unimpaired.

     Baddeley proposed a model of working memory in which a controlling attentional system supervises and coordinates a number of subsidiary slave systems.         
    Three components—(1) central executive, (2) phonological loop, and (3) visuo-spatial sketchpad

 

 

    C. Long-Term Memory

III. Processes

    A. Automatization

Cognitive processes vary in how much attention they require

    Controlled (effortful) processes--require a great deal of attention

    Automatic processes--require very little, if any, attention

    Amount of attention required is influenced by type of information being processed and by amount of experience person has with that type of material

    For types of info. that initially require a great deal of attention, practice can reduce amount of attention required

    Automatic processing is important in development because it provides a ready-made route for learning about the world...e.g, retaining frequency information

    Other processes, however, may change from controlled to automatic as experienced is gained with that type of information...e.g., single-digit addition

    B. Encoding

    Internally representing information

    However, not all information about the world can be encoded...just too complex

    Children must learn to encode important features of objects and events in order to later benefit from the information...must learn to do so efficiently