Researchers from New York and McGill University have discovered that infants can detect how speech communicates unobservable intentions. The study, published in the Proceedings of the National Academy of Sciences (PNAS) provides scientists with a better understanding on how early in life we can rely on language to gain knowledge about matters beyond first-hand experiences.
Co-author of the study, Athena Vouloumanos, an assistant professor at NYU explains:
“Much of what we know about the world does not come from our own experiences, so we have to obtain this information indirectly — from books, the news media, and conversation. Our results show infants can acquire knowledge in much the same way — through language, or, specifically, spoken descriptions of phenomena they haven’t — or that can’t be — directly observed.”
Earlier studies have shown that infants seem to understand that speech can be used to categorize and communicate about observable entities such as objects and people. However, so far there have been no studies to examine whether infants can recognize that speech can communicate about unobservable aspects. The researchers therefore decided to investigate whether one-year-old infants could recognize that speech can communicate a person’s intentions, something that is crucial for understanding social interactions.
The researchers performed an experiment in which adults played short scenarios for the infants. The endings of some of the performed scenes were predictable, i.e. with an ending that is congruent with people’s understanding of the world, whilst other scenes had an unpredicted finish (incongruently).
The team used a common approach of measuring the infants’ detection of unpredictable scenes, meaning that the infant looked longer at these scenes compared with others. In one scene the adult actor (the communicator) attempted to stack a ring on a funnel in front of the infants, but failed because the funnel was out of reach. According to earlier studies the infants would interpret the actor’s failed attempt as a signal of the actor’s underlying intention to stack the ring. The team then introduced a second actor (the recipient) who managed to reach all objects. In the key test scene, the communicator turned to the recipient and either coughed or said a unique word (‘koba’) to the infants.
Even though the infants always knew the communicator’s intention, because they observed previous stacking attempts that had failed, the recipient only sometimes had the information necessary to accomplish the task as intended by the communicator, in fact only when the communicator said the unique word, but not when she coughed.
The experiment’s underlying theory was that if infants understood that speech but not coughing would communicate information about an intention, in that the communicator used speech and the recipient responded by stacking the ring on the funnel, the infants should treat this as a congruent outcome. The theory was confirmed by the results. The infants held their gaze longer when the recipient performed a different action, for instance imitating the communicators’ earlier failed movements or stacking the ring somewhere other than on the funnel, which indicates the infants viewed these events as a surprise or as an incongruent outcomes. The researchers observed that the infants looked equally irrespective of the recipient’s response when the communicator coughed, as coughing does not communicate intentions.
Onishi, an associate professor in the Department of Psychology at Canada’s McGill University, explains:
“As adults, when we hear people speaking, we have the intuition that they’re providing information to one another, even when we don’t understand the language being spoken. And it’s the same for infants. Even when they don’t understand the meaning of the specific words they hear, they realize that words — like our nonsense word ‘koba’ — can provide information in a way that coughing cannot.”
Vouloumanos remarked: “What’s significant about this is it tells us that infants have access to another channel of communication that we previously didn’t know they had,” and concluded saying: “Understanding that speech can communicate about things that are unobservable gives infants a way to learn about the world beyond what they’ve experienced. Infants can use this tool to gain insight into other people, helping them develop into capable social beings.”
Written by Grace Rattue