Serial Position Effect
You are vacationing on the beach with a group of friends. You volunteer to walk to a food stand on the boardwalk to order lunch for everyone. Before you leave, you find yourself repeating each order to make sure you won’t forget any details by the time you reach the stand.
Why is it necessary to repeat these orders before leaving, rather than simply hearing them once and walking away? It’s because you learned in your psychology class that your working memory—the processing system that keeps information available for current use—can only maintain five to nine pieces of information for up to 20 to 30 seconds. You would not remember all the details of the lunch orders by the time you reached the food stand after hearing them just once. So you rehearsed everyone’s orders by repeating them to yourself. This transferred the information into your long-term memory, enabling you to access it when placing the orders a few minutes later.
In the Experience section of this ZAPS lab, your task will be to remember numerous pieces of information, much like the list of lunch orders in the example above. You will see, however, that the order in which the information is presented makes a difference in how well you remember it.
In each trial of this ZAPS lab, you will see 12 words on the screen, one after another. After these words are presented, 12 boxes will appear. Try to remember as many of the 12 words as possible and type them in the boxes. The order in which you fill in the words does not matter, and you can take as much time as you want to type in the words. However, be sure that your final answers do not contain any typing errors. Once you type in all the words you remembered, you can continue to the next trial. There are no practice trials; the experiment starts immediately. In total, you will see five trials with a series of 12 words each.
After viewing each series of words, I must:
· Fill in the words I remember without regard for typing errors.
· √ Fill in the words I remember in any order, being careful that I do not make any typing errors.
· Fill in the words I remember in the exact order in which they appeared.
In this Experience, you were presented with five trials of 12 words each. After each series of words, you recorded as many words as you could remember from that series. You probably began to notice a pattern after attempting to recall words in the first few series: most of the words you successfully recalled had occupied similar positions within their series of 12 words.
This phenomenon is known as the serial position effect. It is a form of memory bias in which our ability to recall a given item from a series depends on its relative position within that series.
In the graph, you will observe how the relative positioning of certain words within a series influences your ability to recall those words. On the x-axis, you will find the position of the word within a series, from one through 12. Plotted on the y-axis is the percentage.
What patterns do you think you will observe in your data from this Experience? For which positions of words within the five series do you hypothesize that you had the highest and lowest percentages of recall?
In viewing your data from the Experience section, you probably noticed a pattern in your responses. You probably weren’t able to remember all 12 items from any given series, and your highest percentages of recall were clustered around the words in the beginning of a series and those near the end. If we perform such an experiment with a large group of people and average all of their responses, the results will resemble the following graph:
This graph, called a serial position curve, demonstrates how people tend to recall items from the beginning and the end of a list. Because the serial position effect involves two different relative positions within a list, we refer to the phenomenon of better recall of the items at beginning as the primacy effect and that of better recall at the end as the recency effect.
Why is it that we don’t simply remember the items from a list in the reverse order in which they were presented? Why is our recall for items in the middle of the list rather low? Researchers Rundus and Atkinson (1970) set out to explore this phenomenon. They found that our ability to mentally rehearse items from the beginning of a list explains our enhanced recollection of them. We cannot rehearse items from the middle of a list as frequently as those at the beginning, explaining our decreased recollection of items from the middle.
Rehearsing items over and over again leads to the storage of these items in long-term memory. For example, if the first word you hear in a memory experiment is apple you may be able to rehearse “apple, apple, apple” before the next word—corner—comes along. Then, you may rehearse “corner, apple, corner” before the next word appears, and so on. However, how would the amount of rehearsal explain better recall of the items at the end of the list? It does not.
Rundus and Atkinson concluded that the recency effect must take place by means of a different cognitive mechanism than that of the primacy effect. While the primacy effect takes place when items enter long-term memory through frequent rehearsal, the recency effect occurs because the items near the end of a list are still present in working memory at the time of recall. In this way, we can easily retrieve the last few items presented in a series.
Under certain circumstances, the primacy and recency effects do not appear in the ways we would expect. Researchers found that if there is a delay in time between the presentation of a list and the participants’ recall of that list, the recency effect disappears, and only the primacy effect remains (Bjork et al., 1974). This occurs because the items from the beginning of the list remain in long-term memory, whereas the items at the end of the list have since disappeared from working memory at the time of recall. In contrast, people who can no longer form new long-term memories—a condition called anterograde amnesia—observe the recency effect when there is no delay, but not the primacy effect. (Carlesimo et al., 1996).
Suppose you are presented with a list of 50 words and you must immediately recall them. What do you hypothesize would happen to the primacy effect when recalling 50 items in comparison to recalling 12 items? Besides list length, what other factors might influence the primacy and recency effects during the recall of a list?
When you remember the first few items from a list better than items in the middle of the list, this effect takes place because the first items were still present in your working memory upon recall.
· √ False
Which of the following best describes the serial position curve for an experiment conducted with a delay between the presentation of a list and participants’ recall of that list?
· √ high percentages of recall for the first few positions in the list and low recollection for all other items in the list
· high percentages of recall for the first few positions in the list, low recollection of the middle items of the list, and high recollection of items at the end of the list
· high percentages of recall in the middle of the list and low recollection of items at the beginning and end of the list
A friend tells you the seven-digit passcode to enter her home. How long will this information remain in your working memory if you do not rehearse it?
· 1 minute
· √ 20–30 seconds
· 3 minutes
· 5–7 seconds