The Ranschburg Effect: what it is and what it shows about memory

The Ranschburg effect shows us how human memory works, and the forgetting associated with it.

The Ranschburg effect, also called Ranschburg inhibition, is a curious memory phenomenon that occurs in an experimental setting.. It consists of omitting or presupposing words, digits or elements that are very similar to each other and that the brain, a posteriori, interprets as one and the same.

The first description of this phenomenon is more than a century old, although scientific research has not dealt with it in much depth. Below we will find out more about how it happens and what factors influence its occurrence.

What is the Ranschburg effect?

The Ranschburg effect is a memory phenomenon that occurs when, when receiving several repeated or similar stimuli, the person is not able to remember all of them..

Experimentally, this phenomenon occurs when a sequence with several repeated words or numbers is presented and, when trying to remember them later, the person tends to make more mistakes or omit elements.

This phenomenon has been related to what has been called guessing strategies.. These strategies would consist in that the person, when he has to remember what has been presented to him, tries to remember by trying to guess one of the elements of the sequence.

If that element was similar to another, the person is likely to decide not to say that element, since he will think that, in reality, he will be wrong. She thinks that the item she thinks she remembers is actually a self-invented repetition.

The Ranschburg effect can be confused with repetition blindness.although they are not the same thing. Repetition blindness refers to the inability to remember a repeated element that occurs in a sequence or set of meaningful words. The person completely omits the repeated element or word, since its repetition is perceived by the brain as superfluous.

An example of repetition blindness would be when we read the following sentence: "When she threw the ink, there was ink everywhere". This sentence makes sense, and it has a repeated word, in this case "ink". Since the brain does not read word by word, but does a quick sweep, making the brain imagine what it is reading based on main words. In this case, since the word ink is repeated twice, its second occurrence is not seenIn other words, it is as if we were briefly blind to that word.

• You may be interested in, "What is the forgetting curve?"

Origins of the concept

The Ranschburg effect is named after its discoverer, the Hungarian psychiatrist Paul Ranschburgwho first described it in 1901. This psychiatrist was particularly interested in memory in psychopathological and neurological processes. A year later he managed to receive international attention with the publication of an article in which he further described this phenomenon.

He originally called it homogeneous inhibition, since it is the difficulty of short-term recall of similar or identical items in a list to be memorized. Thanks to Ranschburg it was possible to understand the difficulty of remembering lists with similar elements, given that in lists with different elements, it is difficult to remember similar or identical elements.Ranschburg's study showed that in lists with different items, it is more likely that all the items presented to the subject will be better remembered.

An example

To better understand the Ranschburg effect, let's look at a practical case in which the phenomenon can occur. Below is a list of three-letter nonsense words with CVC structure.

BEX, DOV, DEX, BOV, DEV, BOX, DOX

This list of words is potentially inductive of the Ranschburg Effectbasically because they are very similar to each other. There are only two types of initial consonants (B and D), two types of intermediate vowels (E and O) and two types of final consonants (V and X). These seven words are very similar and, because of this, if we were to instruct an experimental subject to remember all seven it is quite likely that he would get confused. He would omit some of them, thinking that he is either making them up or has already said them.

In contrast, in the following list, where nonsense words with CVC structure also appear, the Ranschburg effect is much less likely to occur.

DEG, VOK, NUX, ZAJ, KIF, BEL, TON

As with the previous list, there are seven three-letter words, but they are clearly different from each other. They all begin and end with different consonants, and only the vowels E and O are repeated.Trying to remember these nonsense words is easier, since each of them is striking with respect to the others, facilitating their memorization and recall.

Research on this phenomenon

Originally, when this phenomenon was first approached experimentally, it was suggested that its occurrence depended on the simple fact that there were repeated or similar elements in the same sequence, regardless of their position. However, it seems that, in addition to their similarity or repetition, it is the position in the sequence that influences the recall or omission of certain elements..

The Ranschburg effect decreases correlatively as the size of the sequence increases. The more elements, having several that do not resemble each other, the less omission would occur in principle. However, if the repeated or similar elements are very close to each other, regardless of how long the sequence is, there will be less chance of the Ranschburg effect occurring.

For example, in the following sequence, in principle, there would be less chance of the Ranschburg effect occurring:

TIK, NET, BET, SET, FAL, GAP, FIS

In contrast, in this sequence below there would be more chance that the experimental subject would omit one of the two similar syllables:

TIK, NET, FAL, BET, GAP, SETFIS

Repeated or similar elements placed at the beginning or end of the sequence improve the detection rate of the elements, making the Ranschburg effect less likely. This makes sense because this effect is countered by two others well known in the field of memory psychology, namely primacy and recency effects.. The primacy effect is to remember better the things presented at the beginning, while the recency effect is to remember better the things presented at the end.

Error of guessing strategies

Although the term "guessing strategies" should not be considered academic, it is the term we are going to use to refer to the strategies that individuals use to try to completely remember a sequence with similar or repeated elements. People, when we try to remember things, try to fill in the gaps with similar or repeated items, we try to fill in the gaps with a bit of confabulation, i.e., we sort of make up memories..

In the cases of the sequences presented to demonstrate the Ranschburg effect it happens that, since there are elements that are similar or identical, in principle it should be easier for us to remember them. That is, since they are similar or identical, we should not have to invest much effort in remembering something repeated. However, the opposite is true. As we know that we fill gaps in our memory, it happens that, when we remember something that gives us the feeling that it is similar to something we have already said, we assume that we have invented it, something that many subjects would do.

The other explanation for this phenomenon with respect to guessing strategies is that when we try to fill in the blanks we get the feeling that we are not making it up, but that we have a bad memory of some of the elements. of some of the elements. For example, going back to the sequence BEX, DOV, DEX, BOV, DEV, BOX, DOX we have that BEX and DEX are very similar.

It may happen that, when they try to make us remember, we only remember that there was a syllable that had the -EX structure, and we do not remember the consonant in front of it. We are between BEX and DEX, even though there are indeed both syllables. Since we did not remember that there were two and not one, we decided to take a gamble and say only one of the two syllables, thinking that we have a 50% chance of getting it right.

Bibliographical references:

• Greene, R. L. (1991). The Ranschburg effect: the role of guessing strategies. Memory & Cognition. 19 (3): 313-317. doi:10.3758/BF03211155. ISSN 0090-502X. PMID 1861617.
• Hinrichs, J. V.; Mewaldt, Steven P.; Redding, J. (1973). The ranschburg effect: Repetition and guessing factors in short-term memory. Journal of Verbal Learning and Verbal Behavior. 12 (1): 64-75. doi:10.1016/S0022-5371(73)80061-1.
• Stuart-Hamilton, I (2006). The Psychology of Ageing: An Introduction, Fourth Edition. London: Jessica Kingsley Publishers. p. 104. ISBN 9781843104261.
• Henson, R. (1998). Item repetition in short-term memory: Ranschburg repeated. Journal of Experimental Psychology: Learning, Memory, and Cognition. 24 (5): 1162–1181. doi:10.1037/0278-7393.24.5.1162. ISSN 1939-1285.