Sensory memory & Short – term memory

1. Sensory memory & Short – term memory Part I พ.ญ. กาญจนา พิทักษ์วัฒนานนท์ อายุรแพทย์เฉพาะทางระบบประสาทสมอง

2. What is memory ? • Processes involved retaining, retrieving, using information • Original information is no longer present ความทรงจำ ( memory ) คือ ขบวนการทำงานของสมองที่เกี่ยวข้องกับการเก็บบันทึกจดจำข้อมูลที่เรียนรู้ใหม่ๆ การระลึกนึกถึงข้อมูลที่เคยเก็บไว้ หรือการดึงข้อมูลดังกล่าวมาใช้ในกระบวนการคิดและการทำงานต่างๆของสมอง ซึ่งข้อมูลต่างๆเหล่านี้อาจเกี่ยวกับสิ่งเร้าทั่วไป อาจเป็นภาพ เป็นเหตุการณ์ เป็นแนวคิด หรือทักษะความชำนาญในด้านต่างๆที่สมองเคยรับรู้เรียนรู้และมีประสบการณ์มาก่อน โดยสิ่งต่างๆเหล่านี้ล้วนแล้วแต่เป็นสิ่งที่เกิดขึ้นในอดีต ไม่ใช่สิ่งที่เกิดขึ้นอยู่ในช่วงขณะนั้น

3. Memory • Time machine (mental time travel) • To go back just a moment • To the words you read at the beginning of the sentence • To go back many years • To events as early as a childhood birthday party

4. Memory • Time machine : Mental time travel • Place you back in situation • Remember what we need to do later • Remember facts we have learned • Use skills we have acquired • Day-to-day activities

5. Memory ความทรงจำของสมองเปรียบเหมือนเครื่องมือบันทึกข้อมูลสำหรับย้อนเวลาของสมอง ( time machine ) ทำให้สมองมีความสามารถในการย้อนกลับไปนึกถึงสิ่งที่เพิ่งจะเกิดขึ้นชั่วครู่ จนถึงสามารถย้อนกลับไปนึกถึงเหตุการณ์ในอดีตที่ผ่านไปแล้วหลายสิบปีได้ การเดินทางย้อนเวลากลับไปสู่ข้อมูลในความทรงจำของสมอง ( mental time travel ) ทำให้รู้สึกเหมือนเดินทางกลับไปอยู่ในสถานการณ์ที่มีประสบการณ์ในอดีต มีทั้งความรู้สึกนึกคิดต่างๆที่เคยเกิดขึ้นและรายละเอียดของเหตุการณ์ที่เคยได้รับรู้ จนบางครั้งเหมือนกับเหตุการณ์นั้นกำลังเกิดขึ้นอยู่อีกครั้ง ( re experiencing ) นอกจากความทรงจำของสมองจะมีประโยชน์ต่อการระลึกหรือจดจำเหตุการณ์ที่ผ่านมาในอดีตแล้ว ยังมีความสำคัญอย่างมากต่อการใช้ชีวิตประจำวันอีกด้วย ไม่ว่าจะเป็นการจดจำสิ่งที่จะต้องทำในแต่ละวัน หรือแม้แต่กิจวัตรประจำวันเช่นการอาบน้ำแปรงฟันแต่งตัวก็ยังต้องใช้ความสามารถด้านความทรงจำของสมองที่ทำให้เกิดการเรียนรู้และความชำนาญในการทำกิจกรรมต่างๆด้วย

6. Create a “Top 10 list” of : What you use memory for ? Student top 5 items : • Material for exams • Their daily schedule • Names • Phone numbers • Directions to places

7. Top 10 list of purposeswhat you use memory for… Answer : Differ from the ones to the others • Student : material for exams • Construction worker : framing a house • Homemaker : cleaning the house • Business executive : ??? • Politicians : ???

8. Top 10 list of purposeswhat you use memory for… • Most : Day-to-day activities • Labeling familiar objects : “ Book ” is ?? • Having conversations : talking , Q & A • Knowing what to do in restaurant : paying check • Finding the way to somewhere : map

9. How important of memory.. • When people lose their memory.. • What happens to people’s lives.. For example : Clive Wearing

10. Clive Wearing • Musician & choral director in England • Viral encephalitis : destroyed temporal lobe • Cannot forming new memories ( LTM ) • Remember what just happen • Then forget everything else • Problem : he react like 1st meet when he meet someone in a few minutes again

11. Clive Wearing’s diary • He has no memory of ever writing anything except for the sentence he has just written • He is confused • He record events in his handwriting • He has no memory for writing events • He denies that events are his

13. Important of memory • Wearing lives totally within a few minutes • He describes his life as being “like death” • He has no ability to have normal life • He cannot participate in life in any meaningful way • He need to be constantly cared for by others

14. Chapter summery 1 • Memory is the process involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present. • It is important for dealing with day-to-day events, and cases such as Clive Wearing’s illustrate the importance of memory for normal functioning.

15. basic principles of memory : The modal model of memory • Richard Atkinson & Richard Shiffrin’ s : 1968 • Proposed 40 years ago

17. Stages of modal model • Called structural features of the model • There are 3 major structural features • Sensory memory • Short-term memory • Long-term memory

18. Structural features 1 sensory memory • Initial stage • Holds all incoming information for seconds or fractions of a second 2 short-term memory : STM • Holds 5-7 items for about 15-20 seconds. 3 long-term memory : LTM • Hold a large amount of information for years or even decades.

19. Control processes • Active processes that can be controlled by the person and may differ from one task to another. • For example: Rehearsal , Attention , Relating

20. Rehearsal • Repeating a stimulus over and over • You might repeat a telephone number in order to hold it in your mind after looking it up in the phone book.

21. Attention • You selectively focus on other information you want to remember

22. Relating • Relating the numbers in a phone number to a familiar date in history

23. Phone number for Mineo’s Pizza • Rachel looks up the number in a phone book • All of the information that enters her eyes is registered in sensory memory. • Rachel focuses on the number for Mineo’s pizza using the control process of selective attention, so the number enters STM • Rachel uses the control process of rehearsal to keep it there

24. Phone number for Mineo’s Pizza • After Rachel has dialed the phone number • She may forget it because it has not been transferred into long-term memory. • She decides to memorize the number so next time she won’t have to look it up in thephone book. • Transfers the number into LTM

25. Phone number for Mineo’s Pizza • A few days later, • When Rachel’s urge for pizza returns, she remembers the number. • The information must be retrieved from LTM so it can reenter STM to be used.

27. Chapter summery 2 • Atkinson and Shiffrin’s modal model of memory consists of three structural features – sensory memory, short-term memory, and long-term memory. • Another feature of the model is control process such as rehearsal and attentional strategies.

28. Sensory memory • Sensory memory is the retention, • forbrief periods of time, • of the effects of sensory stimulation. • Example : Brief retention for the effects of visual stimulation • The trail left by a moving sparkler • The experience of seeing a film

30. The sparkler’s trial • A sparkler can cause a trail of light when it moved rapidly. • The lighted trail is a creation of your mind, which retains a perception of the sparkler’s light for a fraction of a second. • This retention of the perception of light in your mind is called the persistence of vision.

32. Projector’s shutter A person viewing the film • sees the progression of still images as movement • doesn’t see the dark intervals between the images because the persistence of vision fills in the darkness by retaining the image of previous frame.

33. Flickers of film • The period between the images is too long (more than 24 times/sec.) • Longer dark interval • The mind can’t fill in the darkness completely • A person perceive a flickering effect

34. Sperling’s experiment :Measuring the visual icon • Icon = image • An array of letters (12 icon in matrix) • Flashed on the screen for 50 ms. • 50 ms = 50/1000 sec. • Asked participants to report a whole XMLT AFNB CDZP

35. Sperling’s experiment :Measuring the visual icon The whole report method • They were able to report an average of 4.5 out of the 12 letters • Concluded ??? : the exposure was brief, participants saw only an average of 4.5 of the 12 letters • Perhaps ??? : participants saw most of the letters immediately, but their perception faded rapidly

36. Sperling’s experiment :Measuring the visual icon Determine which of 2 possibilities is correct • Partial report method • Flashed the matrix for 50 ms • Immediately after it was flashed (turned off) • Sounded one of the following cues tones • High pitched : top row • Medium-pitched : middle row • Low-pitched : bottom row • To indicate which row of letters the participants were to report

37. Sperling’s experiment :Measuring the visual icon Partial report method • Sound after flashed off • Actual letters were no longer present • Participant’s attention was directed not to the actual letters • Participant’s attention was directedto whatever trace remained in their mind • Cues tones directed participants to focus their attention onto one of the rows

38. Sperling’s experiment :Measuring the visual icon Partial report method • Result : they correctly reported an average of about 3.3 of the 4 letters (82 %) • Conclude : they saw 82% of letters They were not able to reportall of these letters because they rapidly faded as the initial letters were being reported

40. Sperling’s experiment :Measuring the visual icon To determine the time course of this fading • Delayed partial report method • The presentation of cue tones was delayed for a fraction of a second after the letters were extinguished • Result : delayed for ½ second  report only slightly more than 1 letter in a row • Result : same number of whole report method

42. Sperling’s experiment • Immediately after flashed off • All or most (82%) of stimulus is available for perception • This is sensory memory • Sensory memory registers all or most of the information that hits our visual receptors

43. Sperling’s experiment • Over the next second after flashed off • Sensory memory fades • Information decays within less than second

44. Sperling’s experiment • A short-lived sensory memory registers all or most of the information that hits our visual receptors • Capacity of sensory memory = large • but that this information decays within less than a second. • Duration of sensory memory = brief

45. Duration of sensory memory • Sensory memory for visual stimuli • Iconic memory = visual icon • Persistence of vision • Duration less than one second • Sensory memory for auditory stimuli • Echoic memory • Persistence of sound • Duration lasts for a few second

46. Important of sensory memory • Collecting information to be processed • Holding the information briefly while initial processing is going on • Filling in the blanks when stimulation is intermittent

47. Chapter summery 3 • Sperling used two methods, whole report and partial report, to determine the capacity and time course of visual sensory memory. • The duration of visual sensory memory (iconic memory) is less than 1 second, • The duration of auditory sensory memory (echoic memory) is about 2-4 seconds.

48. Short-term memory • Brief duration • What is the duration of STM ? • Most of information is lost • How much information can STM hold ? • Some of information store to be long-term memory

49. Short-term memory • Whatever you are thinking about right now, or remember from what you just read, is in your STM • How do we understand this sentence ? “The human brain is involved in everything we know about the important things in life, like music and dancing”

50. What is duration of STM ? • John Brown , Lloyd Peterson , Margaret Peterson : experiments to determine the duration of STM • Remembering three letters • Tell the person that you are going to read three letters followed by a number • Once the person hears the number he should start counting backward by 3’s from that number • When say Recall : write down the three letters heardat the beginning • Once the person start counting, • time 20 seconds and say “Recall”