Jean Berko’s wug experiment was a real milestone in the history of psycholinguistics. By presenting artificial words to young children, Berko demonstrated that even at very early stages of life we are able to extract rules from language and apply them to unknown words.

In this article we will see what was the context of the experiment, how it was carried out and what exactly was discovered thanks to it.

Biography of Jean Berko

Jean Berko was born in 1931 in Cleveland, Ohio. In 1958, after studying history, literature and linguistics, he received his PhD from Harvard University with a study in the field of psycholinguistics that would prove extremely influential for including the so-called “wug experiment”, which we will describe in detail in the following section.

Berko has spent most of his career at Boston University, where he worked as a teacher until a few years ago. She is currently retired from this profession, although she continues to engage in research in the field of psycholinguistics.

In addition to his studies and works on language development in the early stages of life, Berko’s work also includes research on vocabulary, aphasia, the acquisition of routines in children and the differences between the language of mothers and fathers.

The Wug Experiment

In his most famous research, which would later become known as “the wug experiment,” Berko worked with children aged 4 to 7. His aim was to analyse the children’s ability to understand the rules of language (specifically the addition of flexible suffixes) and apply them to new words.

To this end, he showed the experimental subjects images of objects and activities that had been given artificial words as names. The most famous example is that of the “wug,” a bluish being vaguely similar in appearance to a bird; in this case, first a single wug was shown and then two identical drawings.

The test itself consisted in presenting the children with unfinished sentences that they had to complete by declining the pseudo-word in question. The text that accompanied the first drawing of the wug said “This is a WUG”; under the image of the two wugs you could read “Here’s another WUG. Now there are two. We have two…”. The children were expected to respond “wugs”.

In addition to the plurals, Berko studied verb conjugations (e.g. past simple), possessives and other common English declensions. With his experiment he showed that young children have already learned the rules of their mother tongue and are able to use them in words they do not know.

He also found that at very early ages children can apply the rules to familiar words but not to pseudo-words; from this he deduced that first the declensions of each word are learned separately and at a more advanced stage the ability is acquired to deduce linguistic patterns and apply them to new words .

Implications for language acquisition

The wug experiment challenged the idea that language is acquired by imitating other people’s words and by reinforcing them. At that time this hypothesis was defended by many learning theorists, particularly in the behavioral orientation.

Since the children who participated in the experiment did not know the artificial words before the test, the fact that they got it right when they declined necessarily implies that they knew the basic rules of their language. After Berko other researchers generalized these results to different languages and contexts.

After its publication, the results of this experiment had a very significant influence on the study of language. Berko’s findings are now firmly established in the scientific theory of language acquisition.

Other contributions by Berko

The rest of Berko’s research can also be included in psycholinguistics, although this author has shown interest in multiple facets of language and its broad influence on learning and behavior.

1. Studies on aphasia

Aphasia is a disorder consisting of a very marked difficulty in the use of expressive and/or receptive language . It is generally due to brain damage and its specific characteristics depend on the location of the damage, so multiple types of aphasia have been described.

Along with Goodglass, Bernholtz and Hyde, Berko argued that the language problems of aphasia cannot be explained either by the presence of stable grammatical errors or by the intentional omission of words to reduce the effort of speaking.

2. Language differences between mothers and fathers

In a 1975 study, Berko found that the interaction of adults with young children seemed to vary according to their sex: while boys gave more orders and reflected traditional gender roles to a greater extent , women adapted their speech more to the characteristics of the child .

Although Berko wanted to generalize these results to the language of mothers and fathers in general, the truth is that the sample of the experiment was composed of only three couples with children and four daycare teachers, two of them women and two men.

3. Acquiring routines in childhood

Berko conceptualized routines as verbal patterns, sometimes accompanied by gestures, that young children internalize under the influence of the cultural context in which they grow up. Particularly noteworthy are his studies on “good manners” , such as greeting, saying goodbye, thanking or apologizing.