A study conducted in the Netherlands discovered that learning new vocabulary in a foreign language can impede the recall of words from another, previously learned foreign language. The research found that native Dutch speakers who learned Spanish translations for English words they already knew experienced more difficulty recalling those English words later. The paper was published in the Quarterly Journal of Experimental Psychology.
Most people had an experience when learning some new information made it difficult for them to recall information they had previously learned. This phenomenon is called retroactive inhibition. Retroactive inhibition works by interfering with the memory consolidation process. When new information is learned, it can disrupt the stabilisation and integration of previously learned information into long-term memory.
This disruption occurs because the brain has limited resources for processing and storing information, and the new information competes with the old for these resources. As a result, the recall of the earlier information becomes more difficult, leading to a decrease in memory performance for that information.
Studies have shown that knowledge of different foreign languages competes with each other. Due to this, when, for example, a person speaking multiple foreign languages wants to recall a word for a specific object, it often happens that a word in a different language comes to the person’s mind. In some cases, the person might not be able to recall the word in the desired language at all, particularly, if the person has not been using the language for a long time.
Study author Anne Mickan and her colleagues wanted to investigate if, and under which circumstances, new language learning hampers access to previously learned and well-consolidated foreign language words. They conducted two experiments.
In the first experiment, 31 native Dutch speakers, all of whom had English as their second language and no prior knowledge of Spanish, participated. Initially, they completed a vocabulary test to confirm their familiarity with certain English words. They then learned Spanish translations for half of these English words, potentially creating interference with their memory of the English words. Subsequently, the researchers evaluated how quickly and accurately the participants could recall the English words.
The second experiment involved 86 native Dutch speakers who had not participated in the first experiment. All reported English as their primary and most frequently used foreign language and had no knowledge of Spanish. This experiment replicated the first, with the addition that the initial English vocabulary test was conducted one day before the participants learned Spanish words.
Following the Spanish language session, the participants were divided into two groups: one took the second English test the same day, while the other took it a day later, allowing researchers to assess the impact of overnight knowledge consolidation. An additional test evaluated the participants’ acquisition of Spanish words.
The first experiment’s results indicated that learning Spanish words did not affect the accuracy of recalling English words; participants were equally accurate regardless of whether they learned Spanish translations. However, they were quicker to recall English words for which they did not learn Spanish translations.
In the second experiment, the researchers observed interference effects affecting both the accuracy and speed of recalling English words. Participants were more accurate and faster at recalling English words for which they had not learned Spanish translations.
Notably, the group that had an extra day to consolidate their Spanish learning showed a greater difference in recall accuracy and experienced a more pronounced acceleration in their responses on the English vocabulary test, especially for words without Spanish translations.
“This study provides the first empirical evidence of the detrimental effects that learning words from a new language can have on remembering words from previously learned foreign languages,” the study authors concluded.
“Multilinguals are thus not wrong in their perception that adding a language to their repertoire will, at least during the first stages of learning the new language, hamper access to other foreign languages, even when those languages were learned a long time ago and to a high level of proficiency. Our results, furthermore, suggest that these effects emerge immediately, and do not critically depend on consolidation time for the newly learned language words.”
The study sheds light on how retroactive inhibition affects language learning. However, it should be noted that the study was done on just a selection of words that were learned for the first time and were temporally very close to the time of learning. The long-term effects of learning new languages might not be the same.
