Serial Position Effect

by

Amy Mole¢

Introduction

        Before the memory research conducted by German psychologist Hermann Ebbinghaus, little was known about the processes of memory and memory loss (Ebbinghaus and the Forgetting Curve 1).  Ebbinghaus had a certain “fascination” with finding the causes of why people forget (Ebbinghaus 1).  Ebbinghaus “helped move memory from a philosophical issue to a psychological issue when he developed a means to ‘measure numerically’ and ‘quantify’ the process” (1).  For example, in his book Memory: A Contribution to Experimental Psychology, Ebbinghaus studied the storage of lists of items in short-term memory in order to further test the amount of maintenance rehearsal needed to encode the information into long-term memory (Chapter V 1-5).  (* An example of one of his most famous discoveries can be found in Appendix A: Ebbinghaus Curve and Learner Retention).

        Throughout his studies, Ebbinghaus dealt with the concept of serial position effect.  First described by F.E. Niper in 1878, serial position effect can be defined as a “U-shaped relationship between a word’s position in a list and its probability of recall” (Serial Position Effect 2).  In other words, serial position effect describes the tendency for people to remember items towards the beginning and end of a list rather than those items in the middle.

Explanation of the Topic

            Several characteristics constitute the theory of serial position effect.  First, the remembrance of items occurring towards the beginning of a list is referred to as primacy effect (Serial Position Effect 3).  On the opposite end, remembering items at the end of a list is recency effect.  Both of these effects have been empirically supported through hundreds of experiments  and regardless of “whether lists are visually or verbally presented” (Knoedler, Hellwig, and Neath (1999) cited in Serial Position Effect 3).  Finally, positional theory is the third characteristic that allows everything to fall into place.

Primacy

Primacy describes the notion that items towards the beginning of a list are rehearsed more than the other items (Rehearsal Hypothesis cited in Serial Position Effect 4.)  Another explanation suggests that this higher rate of rehearsal transfers recollection of the items into secondary storage, which would then make the items easier to call (Theory of Serial Position Effect 1).  These ideas root from the practice of maintenance rehearsal.  Maintenance rehearsal “is the continual repetition of a piece of information in order to hold it in current memory for use in problem solving or transferal to long-term memory” (Hawkins, Best, and Coney 347).  Sound familiar?  This was the major focus of Hermann Ebbinghaus’ memory research.

Recency

According to Waugh and Norman (1965) and Atkinson and Shiffrin (1968), there are two locations in memory: short-term and long-term, and recency effect comes directly from short-term memory (Serial Position Effect 6).  The idea of recency effect makes sense because after a subject is presented with a list and the list is removed from sight, the items towards the end of the list are usually remembered first (Welch and Burnett (1924) cited in Serial Position Effect 3).  This foremost remembrance, according to the author of Theory of Serial Position Effect, occurs because there has been little or no decay of the items due to their most recent storage and non-interference with earlier items in the list (1). 

Positional Theory

Positional theory “assumes order is stored by associating each element with its position in the sequence” (Henson 77).  How are these positional codes “stored and retrieved from memory” (Henson 78)?  As suggested by Brown, Preece, Hulme, Burgess, and Hitch, “the codes are derived from temporal oscillators in the brain.  [Oscillating is the indecisive swaying ‘from one course of action or opinion to another’ (Costello, et al. 588, 886).]  Elements can be associated with successive states of the oscillators, and these states reconstructed simply by resetting the oscillators” (Cited in Henson 78).  Therefore, the successive state of each oscillators is improved through primacy and recency effect.  Through the uses of primacy and recency effect, positional theory provides the evidence as to how these effects interact in memory to derive serial position effect.

Serial Position Experiments

        A helpful way to understand a topic completely is to participate in its actual process.  Two separate serial position experiments exist on the Internet, one that uses free recall, and the other that incorporates assisted recall.  The first of the two experiments uses only one trial.  It presents a list of 10 letters for approximately 15 seconds, and then removes the list and then you are prompted to type in the letters that you can remember into the appropriate text box.  This is free recall (unaided retrieval of items in short-term memory).   I participated in this experiment, and I recalled more items from the beginning and end of the list rather than the middle. Free Recall Experiment        

        Instead of the use of free recall, the second experiment uses assisted recall.  The experiment consists of 15 trials, where each trial flashes a sequence of letters and then provides a list of the letters of the alphabet for you to choose the letters from that you can recall.  Since the letters are provided as cues in memory, this is what classifies the experiment as a use of assisted recall. The results show the true effects of serial position, as my rate of recall was high in the beginning, took a deadly drop in the middle, and gradually rose towards the end. (Editor's note: The experiment to which Amy refers is now password protected and is no longer publicly available on the Internet - Dr. Drea)

 However, for right now, let's try a little experiment of our own:

1. Get a pen/pencil and piece of scratch paper.

2. Examine the following list of grocery items for 30 seconds:

Now scroll down this page so the list is no longer visible. (Do not peek back at the list!)

keep scrolling...

keep scrolling...

3.    Now, on the piece of scratch paper, write down as many of the items that you can remember. (Remember, no peeking back up at the list!!)

4.    Check your results - do they imply a serial position effect (i.e., did you remember more of the items at the start and end of the list?)

Examples of Serial Position Effect in Advertising

            Several instances of serial position effect are relevant in the field of advertising.  Now that you have an understanding of the topic, consider the following advertising examples:

         How can serial position effect play a role in the amount of information that your consumers will remember from your advertisements?    Not only does positioning theory affect free and assisted recall of items from lists, it can affect the portions of your advertisements that consumers can recall as well.  Think of a television or radio commercial’s structure as a list.  Similar to a list, these advertisements also have structural features that consist of a beginning, middle, and end.  Therefore, the theory also would imply that people tend to remember information from the beginning and end of television commercials.  This idea can also be applied to the entire order of a television or radio commercial sequence.  Therefore, when planning this type of advertisement, you should definitely consider placing the most important information at the beginning and end of the commercial, and secondly, you should place the commercial at the beginning or end of the advertisement sequence.

        Another example of serial position in advertising exists when consumers observe magazine, billboard, Internet, and newspaper (or any other similar) advertisements.  The importance of effective positioning of words, logos, graphics, etc., so consumers will remember them is essential.  Again, the most important information that you would like consumers to remember from these types of advertisements should be positioned towards either the beginning or end of the page.   

Relevant Web Sites

             Several Internet web sites clearly explain the ideas that surround serial position effect.  The following web sites include extensive examples, background, and attributes that can be linked to the topic.  Below you will find the web addresses of each site along with a brief explanation of what each web site entails:

            http://www.yorku.ca/dept/psyco/classics/Ebbinghaus/memory5.htm

-A chapter of Hermann Ebbinghaus’ original memory studies inspired by his fascination with forgetting.
-Provides examples used throughout the study.
-Links serial position effect to maintenance rehearsal.

http://www.geocities.com/Athens/Atlantis/6724/IntroPsychEbbing.html

and

http://www.mindspring.com/~frudolph/lectures/Mem/memory.htm
 -These provide background behind Hermann Ebbinghaus’ memory research.

 http://www.v-page.com/training/hermann.htm
-Displays a graph of Ebbinghaus’ rate of recall study.

 http://dushkin.com/connectext/psy/ch07/freerec.mhtml

 -Provides a smaller serial position experiment than the one above for any user to conduct.

 http://www.science.wayne.edu/~psy3090/lectures/serpos/sld001.htm

 -Provides a slide show that defines serial position effect through lists and free recall.
-Shows characteristics, explains characteristics, and provides support towards the topic through reasons for studying serial position curves.
-Links and explains primacy effect and regency effect and their theorized   roles in serial position effect.

             http://www.princeton.edu/%7Erdnelson/series.html
                -Provides a brief explanation of psychological links to serial position effect.

             http://coglab.psych.purdue.edu/coglab/SerialPosition/SP.html
                -Provides an actual serial position experiment for any user to conduct.

 http://freud.psy.fsu.edu/~charness/dep4400s97/Lecture6/sld009.htm
-Portrays the course of serial position effect through primary and secondary memory.
-Provides evidence for the theory.

Test for Understanding

 Now that you have been enlightened in regards to serial position effect, I have provided a short quiz that consists of five multiple-choice questions to ensure your understanding of the topic.  Choose the best answer for each of the questions below:

1.  Which of the following is NOT a characteristic of serial position effect?

(a) Primacy effect
(b) Recency effect
(c) Social effect
(d) All of the above are characteristics.

 2.  According to the Theory of Serial Position Effect, when repeating items from a list using free recall, people tend to remember:

(a) items towards the middle of the list.
(b) items towards the end of the list.
(c) items towards the beginning of the list.
(d) both b and c.  

 3.  Which of the following is a use of serial position effect in advertising?

(a) Place important information at the beginning and end of your advertisements.      
(b) Place your advertisement at the beginning or end of a radio or television commercial sequence.
(c) Both of the above are uses of serial position effect in advertising.
(d) None of the above are uses.

 4.  Positional Theory suggests that

(a) people that have never served in the military should not hold a position as President of the United States.
(b) lists are encoded into a certain storage section of the brain.
(c) people store items from a list according to their position in sequence.                     
(d) None of the above.

5.  Hermann Ebbinghaus

(a) conducted important research that involved memory and memory loss, which can be attributed to what we know about memory today.
(b) proved that serial position effect does not exist.
(c) used cats to conduct memory research.
(d) discovered the lost city of Atlantis.

 <scroll down for answers>

            Answers: 1-c, 2-d, 3-c, 4-c, 5-a

References

Costello, Robert B., at el.  The American Heritage Dictionary.  Houghton Mifflin: New York, 1994.

Ebbinghaus, Hermann.  (1885), “Rapidity of Learning Series of Syllables as a Function of Their Length.”  Memory: A Contribution to Experimental Psychology.  http://www.yorku.ca/dept/psyco/classics/Ebbinghaus/memory5.htm [16 March 2000].

“Ebbinghaus.”  http://mindspring.com/~frudolph/lectures/Mem/memory.htm [17 March 2000].

“Ebbinghaus Curve and Learner Retention.” http://www.v-page.com/training/hermann.htm [16 March 2000].

“Ebbinghaus and the Forgetting Curve.”              http://www.geocities.com/Athens/Atlantis/6724/IntroPsychEbbing.html [15 March 2000].

 “Free Recall Test.”  Web Activity. http://dushkin.com/connectext/psy/ch07.freerec.mhtml [14 March 2000].  A Division of The McGraw-Hill Companies, 2000.  

Hawkins, Del I., Roger J. Best, and Kenneth A. Coney.  Consumer Behavior: Building Marketing Strategy.  Boston: McGraw-Hill, 1998.

 Henson, Richard N. A.  “Short-Term Memory for Serial Order: The Start-End Model.”  Cognitive Psychology. 1998 July, 36(2), 77-78, 80-81.

 “Serial Position Effect.” http://www.science.wayne.edu/~psy3090/lectures/serpos/sld001.htm [16 March 2000].

“Serial Position Task.”  Cognitive Psychology – Serial Position – Purdue University. http://coglab.psych.purdue.edu/coglab/SerialPosition/SP.html [14 March 2000].