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Poster #13 - Nine-Month-Old Infants Update Their Predictive Models of a Changing Environment

Thu, March 21, 2:15 to 3:30pm, Baltimore Convention Center, Floor: Level 1, Exhibit Hall B

Integrative Statement

NINE-MONTH-OLD INFANTS UPDATE THEIR PREDICTIVE MODELS OF A CHANGING ENVIRONMENT

Humans generate internal models of their environment to predict events in the world. As the environments change, our brains adjust to these changes by updating their internal models. Here, we investigated whether and how 9-month-old infants differentially update their models to represent a dynamic environment.
In an audio-visual electroencephalography (EEG) paradigm, we presented infants with a continuous sequence of stimuli which followed a predictable pattern (i.e. same stimuli were repeated for several trials; “expected” trials). Two types of cues (i.e. “update” and “no-update”) were interspersed among the expected trials, which differed in terms of whether or not they signaled a future change in the sequence. Following the “update” cue, the predicted pattern was altered, whereas the pattern remained the same after the “no-update” cue (Figure 1). Therefore, infants were expected to update their predictions about the upcoming targets when they observe the update cues; however, they were expected to not change their predictions following the no-update cues.
We predicted that the two types of unexpected cues would elicit an amplified negative central (Nc) response in contrast to the expected stimulus, if infants indeed perceive them as unexpected. As hypothesized, data revealed that both in the “update” (md = -3.89, SE = 1.17, p = 0.003) and the “no-update” trials (md = -5.68, SE = 2.18, p = 0.017), infants showed significantly stronger negativity in comparison to the expected trials. There was no significant difference in responses between “update” and “no-update” trials in the early stages of processing (md = 1.79, SE = 2.03, p = 0.390).
Based on our hypothesis on updating, we tested whether infants dissociated between the two unexpected cues and showed larger positive slow wave (PSW) in “update” trials as compared to the other trial types. These analyses revealed that participants showed more positivity in response to both “update” (md = 2.82, SE = 0.88, p = 0.004) and the “no-update” trials (md = 4.18, SE = 1.65, p = 0.020) as compared to the expected trials. This finding suggests that the unexpected information modulated infants’ responses in later stages of processing as well; however, no differential response to the two types of cues was observed at later stages of processing.
To explore the nature of the internal models infants might have generated throughout the experiment further, we investigated infants’ neural responses to the stimuli following the “update” and “no-update” cues. These analyses showed that infants associated unexpected cues with future changes in the sequence. Interestingly, only when a predicted change was absent (i.e. following the “no-update” cues) a prominent neural response was observed in the early components indicating a top-down modulation of early sensory processing in infants. Our study corroborates emerging evidence suggesting that the basic machinery to build predictive models might already functional early on in life. Importantly, our study shows that infants modulate their predictive models of the environment dynamically to maintain an accurate representation of the world.

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