Conversation possible even with ambiguous expressions — Differences in interpretation of recency and rarity between children and adults clarified by Kyushu University

"Did you see that?" In everyday conversation, even if we use such highly ambiguous phrasing, we can still make sense of it because the listener can successfully interpret what is being said based on context. Previous research has shown that "temporal proximity" and "salience" can provide clues for interpreting ambiguous utterances ("Temporal proximity" or "recency" refers to something close in time. "Salience" or "rarity" refers to something that stands out in a situation.) However, it was unclear how the two interact.

Professor Kazuhide Hashiya and Research Fellow Reiki Kishimoto of Kyushu University's Graduate School of Human-Environment Studies have developed a new method using animation. They conducted experiments to manipulate temporal proximity and salience in a sequence of events and found that school-age children were more likely to focus on temporal proximity; however, adults interpreted rarity and temporal proximity together. In other words, the process of integrating rarity and recency differs across developmental periods. This finding will contribute to the development of interactive robots to support the development of children who have issues communicating with others. The research was published in PLOS One.

The study developed a new method for quantitatively manipulating rarity and recency. Nine pipes were arranged horizontally on a screen. Identical-looking "monsters" jumped out, one by one, from left to right. The "monsters" performed an action such as playing an instrument or eating something. They then withdrew back into the pipe. Among them, there was one "monster" who did something different. That is, the timing at which a rare event occurred was manipulated, as was the recency of the rare event.

After the nine events were over, participants were asked, "Did you see that?" The question was asked through embedded audio. The participants then used a touch screen to indicate which event or events they thought the question was referring to. The participants could select any number of events.

This task was performed by 82 children aged 7-10 years and 36 adults. Most of the responses focused on rare or recent events. Detailed analysis revealed that, overall, children were more likely than adults to select recent events. They placed more weight on recency than adults did. Furthermore, children's selection rate for rare events increased only when the rare event had been presented immediately before. Adults, on the contrary, demonstrated increased selection rates for rare events as the recency of the rare event increased. This indicates that both children and adults integrate rarity and recency, but in different ways. For children, the effect of rarity affects interpretation independently of temporal proximity, whereas for adults, rarity and temporal proximity are integrated in an interactive manner.

The researchers want to experiment with multiple languages in the future. Kishimoto said, "The nature of communication is rapidly changing. This is partly because of the rise of communications devices and social media. The true nature of human communication is being called into question. This study has revealed differences between children and adults in speech interpretation. Thus, I hope it will shed light on these issues. In the future, we'd like to conduct similar experiments with multiple language speakers to examine the interactions between the characteristics of each language and culture. Conducting the experiment was a really tough task to create a program that linked various visual stimuli with tablet operations. I'm delighted that the project has produced results."

Journal Information
Publication: PLOS One
Title: Recency and rarity effects in disambiguating the focus of utterance: A developmental study
DOI: 10.1371/journal.pone.0317433