Short Term Memory Flashcards
What is proactive interference?
Memory for one event is impaired by earlier events.
Example: Not remembering where you parked your car today because you’re thinking of where you parked yesterday instead.
What did the Backward Counting Between Study & Recall (Glanzer & Cunitz, 1966) study do to build on the Serial Position Curve study?
Participants spent time
(Three conditions: 0, 10, or 30 seconds) counting backward after the last word of the study phase.
The hypothesis was that this would remove recency effects because too much time would have passed without rehearsal, thus removing the recent words from STM.
What is free recall?
Non-cued recall where order doesn’t count
What are the two types of non-cued recall?
Serial and free
What is decay?
Forgetting because of the passage of time
What was the independent variable in the Brown-Peterson Task?
The amount of time spent counting backwards from the 3-digit number.
What was the dependent variable in the Probe Digit Task (Waugh & Norman, 1965)?
The percentage of correct recalls.
What is serial recall?
Non-cued recall where order matters
What was the main purpose of the Probe Digit Task?
To disentangle effects of time and interference (seen in the Brown-Peterson Task).
How long does short term memory last?
Technically STM can last forever if we’re constantly rehearsing, so we want to know how long it can last without rehearsal
What was the procedure of the Serial position curve (Rundus, 1971) study?
Participants were read 20 nouns from a video tape.
They were given 5 seconds between each word for rehearsal.
Audio was recorded to count how many times participants rehearsed each word.
Immediately after the last word, participants were asked to “free recall” all of the words they heard.
What is retroactive interference?
Memory for one event is impaired by later events.
Example: Not remembering where you parked your car yesterday because your new spot today is interfering.
What were the results of the Probe Digit Task (Waugh & Norman, 1965)
No significant difference between the slow and fast conditions, but greater amounts of intervening digits between probe appearances led to lower recall rates.
What is cued recall?
Given words like water and fall, then given water and expected to say “fall”.
What are recency effects?
When the list ends, the last few items are still hanging around in the STM, so recall probability increase for items at the end of a list.
How did the Manipulations of List Length (Murdock, 1962) study build on the Serial Position Curve study?
Using only 1-second gaps between items, they manipulated the length of the list. Three conditions: 10, 20, and 40 item lists.
What are the two types of interference?
Retroactive Interference and Proactive Interference
What is interference?
Forgetting because of shifting attention to new material (like counting backward)
What were the Independent Variables in the Probe Digit Task (Waugh & Norman 1965)?
The rate of reading:
Slow or Fast.
The amount of intervening items appearing between the two appearances of the probe digit.
What were the conditions in the Probe Digit Task (Waugh & Norman, 1965)?
Slow reading rate: 1 item per second.
Because of the slow speed, there was a longer period of time between the first appearance of the probe and the final appearance of the probe - more decay.
Fast reading rate: 4 items per second.
Shorter delay = less decay.
The amount of intervening items appearing between the two appearances of the probe digit.
What is recognition?
See words or pictures and asked which you previously saw in a study phase.
What did the Rate of Presentation During Study (Glanzer & Cunitz, 1966) study do to build on the Serial Position Curve study?
They added three conditions: 1, 2, or 3 second gaps between words in order to shorten rehearsal time.
What was the purpose of counting backwards in the Brown-Peterson Task?
This was a distractor task to prevent participants from rehearsing the 3-letter trigram.
What are the two types of recall tasks?
Cued and non-cued
Which type of interference caused forgetting in the Brown-Peterson Task?
Retoactive Interference
What were the results of the Brown-Peterson Task?
The longer amount of time spent counting backwards, the worse the recall rate.
What were the results of the Backward Counting study?
The longer the period of time spent counting backward, the less participants were able to recall words at the end of the list.
This removed recency effects.
Name two causes of forgetting
Decay and Interference
In the Probe Digit Task (Waugh & Norman, 1965) what was a “probe digit”?
The final digit in a list of numbers.
This number had also appeared at some point earlier in the list, and participants needed to identify where it appeared in the list the first time.
Describe the procedure of the Probe Digit Task (Waugh & Norman, 1965)
Within participants design (over the course of multiple days).
Participants heard a list of 16 digits. On the final digit, participants heard a tone which told them this was the “probe digit.” This “probe digit” appeared somewhere else on the list as well.
Participants were then asked to recall the position of the probe digit (first instance) on the list, along with the digit that came after it.
What were the results of the Rate of Presentation During Study (Glanzer & Cunitz, 1966)
There was a subtle decrease in primacy effects for the shorter rehearsal times.
What is primacy?
Because of extra rehearsal time for the first few items on a list, those items get transferred to LTM, which means recall probability increases for items at the beginning of a list.
What were the results of the Serial position curve study (Rundus, 1971)?
Up to item 14, there is a strong correlation between the amount of times rehearsed and the likeliness to recall the word.
There was a high recall probability for the words heard early and late, but low for the middle items.
People tend to first recall the most recent 5-7 items, and then move to the words they heard at the beginning of the list.
Describe the procedure of the Brown-Peterson Task (Brown, 1958); (Peterson and Peterson, 1959)
Participants saw a 3-letter trigram (3 letters not standing for anything) followed by a 3-digit number. After the 3-digit number, participants counted backward from that number until stopped by the experimenter.
What were the results of the Manipulations of List Length (Murdock, 1962) study?
List length had no effect on primacy and recency effects. However, words in the middle of the list went down in recall for longer list lengths.
As a side-note, this showed that the particular words had no effect on recall, which adds support for the Serial Position Curve.
What was the problem with the Brown-Peterson Task?
The cause of forgetting was confounded because there was no way to isolate decay and interference. The interference task (counting backward) automatically passed time.
