Treisman (1960)

1
Treisman (1960)

• Used shadowing task
• Listen to one ear I saw the girl / song was
  wishing (correct answer)
• Ignore other ear me that bird / jumping in the
  street
• Results people cant help but switch over to
  other message that they are ignoring

2
Interpretation of results

• Support late selection ? people were processing
  the meaning of the ignored message

3
Recent selection model

• Pashler (1998) (p. 65)
• Both early and late selection occur
• Early selection is done in a bottleneck-like
  fashion (some material is completely shut out)
• Late selection done through capacity sharing ?
  split capacity to process multiple messages

4
Generality of selective attention concepts

• Shadowing experiments involve auditory
  information
• But, similar concepts and theories for visual
  information, as well

5
Information Processing Model
SENSORY STORE (e.g, ICON)
STM
SENSATION
PERCEPTION
ATTENTION
6
Short-term Memory

• Aka, the short-term store (old-fashioned)
• Aka, working memory (temporary storage of
  information to do a task)
• Aka, short-term working memory
• Aka, primary memory (James)

7
Try these math problems

• 4 X 9 _____? Answer 36 (remember directly,
  dont have to figure out)
• 35 X 8 ______? Answer 280 (you computed this
  in your head)
• 261 X 97 ______? Answer 25,317 (very very
  difficult to do in your head)
• Problem -gt information gets jumbled in your head

8
Interpretation

• There is a limit on how much information we can
  keep track of in our heads at a time (aka, a
  capacity limit)
• Capacity limit is related to your short-term
  memory (in other words, your short-term has a
  limited capacity for holding information)

9
How much does STM hold?

• Use digit span task
• Hear a list of random digits (single digits)
• Repeat back in order
• E.g., 4 8 1 3 5
• Gradually increase the length of the list
• Keep going until you make mistakes
• Commonly between 4 and 10 digits

10
interpretation

• Your digit span number of digits that you can
  repeat back without mistakes
• Conclusion can hold only a little bit of
  information in short-term memory at a time

11
Capacity of STM

• Are multiple methods for measuring capacity of
  STM
• But estimates are always comparable
• Miller analyzed numerous tasks to estimate STM
  capacity ? 7 /- 2
• Can hold 7 /- 2 items in STM
• chunk ? the item in STM can be an individual
  item or can be a meaningful chunk of items

12

• In digit span task, use individual digits (e.g.,
  1)
• Alternatively could use letters, (now called
  letter span task) ? spans in same range as digits
• Alternatively, could use words (e.g., milk eggs
  celery chicken etc.) (now called word span task)
  ? same results

13

• But, one word is composed of several letters, so
  7 /- 2 words is many more letters than 7 /- 2
  letters
• What you are remembering is chunksnot individual
  letters
• Chunk meaningful unit

14
3 things to know about a memory structure

• Capacity how much it can hold
• Duration how long information is held
• Sensory memory ? less than 1 second
• STM ? up to 30 seconds
• Code (or Format) the way in which information
  is held in memory

15
Different codes

• Reflect how your mind stores information in
  memory (similar to computer using 1s and 0s)
• General possibilities
• Acoustic code information stored in terms of
  how it sounds
• Visual code in terms of looks
• Other codes tied to senses olfactory (smell),
  tactile (touch), gustatory (taste)

16
More on codes

• Semantic code refers to the meanings of things
• E.g., letter span task, hear the letter C
• Acoustic code for C see
• Visual code for C C (what it looks like)
• Semantic code for C 3rd letter of alphabet
  average grade