Sperling (1960)Estimating the Iconic Memory Capacity: Whole report and partial report methods Dr. Timothy Bender Psychology Department Missouri State University 901 S. National Avenue Springfield, MO 65897
Whole Report Method Sperling (1960) is a classic study of the characteristics of the iconic memory (visual sensory memory). One characteristic of the iconic memory that Sperling explored was its capacity, or how much information was available in a single, brief exposure to a visual stimulus.
Whole Report Method At that time, a common method for studying the capacity of the iconic memory was the Whole Report Method. In that method, research participants would be briefly exposed to a visual stimulus, then asked to recall as much of the information as possible.
Whole Report Method In Sperling’s research, the participants might see a 2x4 array of letters for 50 milliseconds. They then had to report what letters they saw and in what position. D J W P B S L M
Whole Report Method In order for you to get a feel for what that is like, you will see several slides. Each slide has a 2x4 array of letters. The first array will appear for about one second or 1000 milliseconds. Operating hint: To move to the next slide after each example, be sure the cursor is near the edge of the screen and is in the shape of an arrow. If the cursor is near the middle of the screen and is the shape of the pointing finger, you will repeat that slide.
Whole Report Method The next array will appear for nearly 500 milliseconds.
Whole Report Method The next array will appear for nearly 100 milliseconds.
Whole Report Method Sperling’s participants frequently were exposed to an array of letters for only 50 milliseconds!
Whole Report Method Sperling manipulated both the number of letters in the arrays (experiment one) and the duration of the arrays (experiment two). He found that neither the number of letters nor the duration of the display had an appreciable effect on the results. In general, his participants could remember a maximum of between 4 and 5 letters.
Whole Report Method • Procedure: • After the next slide, you will see 10 stimuli. • Each stimulus will start with a slide telling you to get ready. Click on that slide to see the actual stimulus. • Then you will see a + sign in the middle of the screen. Focus on the + sign. • The + sign will remain for about 1 second and will be followed by a 3x4 array of letters. • The array will last for about 70 milliseconds. • Then you will be asked to record the letters from the array.
Whole Report Method Your job is to write down the letters in their correct positions as quickly as you can. It is important that you write down a letter in every position, even if it feels like a guess. However, do NOT just write down all Xs or something like that. Also, do not focus only on one row. That actually may reduce your overall score.
Whole Report Method Scoring Procedure • For each array, give yourself one point for each letter in the correct position. • Add up your points for all 10 arrays. • Divide that number by 10 to get your mean number of letters.
Whole Report Method 1 TPBW 2 BFJD 3 KGLC 4 SJKB QNRL KSWZ RBDX VLNY GXKJ DHMZ FJNT BFHD 5 CKMF 6 LHNG 7 TLOH 8 DMPL JTXW QCGV WKRT FVZP FPSY FJPL DGJK HLRX 9 MPQK 10 VNRJ SDHR TMQS CGSM FJLH
Sperling (1960) found that his participants could recall between 4 and 5 of the letters. (If you did as well, that is great. If you did not, do not worry about it. His participants also had more practice than you did and completed the task as individuals rather than in a classroom.) Whole Report Method
One problem with the Whole Report Method is that participants claimed that they saw more letters than they could remember. Apparently, in the time it took to write down the first few letters, the memory for the others was gone. So, Sperling (experiment 3) developed a different technique, called the Partial Report Method. Partial Report Method
In the Partial Report Technique, the participants only had to report one row of the stimuli. They were signaled as to which row of the array to report. The signal was a tone that occurred at the offset of the array and the rows were randomly selected. That way, the participants could not predict which row would be required. The number of letters they recalled from the row was then multiplied by the number of rows to get their score. Partial Report Method
The logic behind the Partial Report Method is clear. If a participant could recall X letters from any one row, then the participant had available in memory X x Y letters, where Y is the total number of rows. Partial Report Method