Joint attention begins emerging in the first six months of life and continues developing through age three, with the most dramatic changes happening between 9 and 18 months. It’s not a single skill that switches on at one age. Instead, it unfolds in stages, starting with simple gaze following and building toward the ability to deliberately direct someone else’s attention to something interesting.
The Two Types of Joint Attention
Researchers break joint attention into two distinct skills that develop on different timelines. Responding to joint attention (RJA) is the ability to follow where someone else is looking or pointing. Initiating joint attention (IJA) is the ability to use your own gaze, gestures, or pointing to draw someone else’s attention to something you find interesting. Responding develops earlier than initiating, which makes intuitive sense: it’s easier to follow someone’s lead than to take the lead yourself.
In a study of 95 infants tracked from 9 to 18 months, responding to joint attention showed steady, linear growth. At 9 months, infants correctly followed another person’s gaze or point about 23% of the time. By 12 months, that jumped to 48%. By 15 months it reached 63%, and by 18 months it plateaued around 68%. The biggest leaps happened between 9 and 15 months, with relatively little change after that.
Initiating joint attention followed a more uneven path. Infants showed fairly steady levels at 9 months, a slight increase at 12 months, a dip around 15 months, and then a rebound at 18 months. That mid-range dip likely reflects the cognitive reorganization happening as infants develop new ways of communicating, including early words, that temporarily compete with their nonverbal bids for shared attention.
What Happens Before 9 Months
The groundwork for joint attention starts much earlier than most people expect. By 3 months, infants can follow an adult’s gaze in certain situations, particularly when a caregiver turns to look at something away from the baby. At 6 months, this ability starts broadening. Research from the Max Planck Institute found that around 6 months, infants enter a transition period where they begin following others’ attention in a wider range of contexts, not just when someone turns away from them.
These early months are dominated by face-to-face interactions. Babies lock eyes with caregivers and respond to facial expressions, but they aren’t yet coordinating attention between a person and an object. That three-way connection, where baby, caregiver, and object are all linked, is what makes joint attention different from simply making eye contact.
The Shift to True Gaze Following
A critical distinction emerges between 9 and 11 months. At 9 months, infants follow head turns, but they don’t actually care whether the person’s eyes are open or closed. They’ll follow the movement regardless, which means they’re tracking head motion rather than understanding that someone is looking at something. By 10 to 11 months, infants sharply differentiate between open and closed eyes, following the turn only when the adult can actually see. This is the point at which babies shift from “head following” to genuine gaze following, a foundational piece of joint attention.
Pointing and Sharing Interest
Around 12 months, a new tool enters the picture: pointing. At first, pointing tends to be a request. A baby points at a cookie on the counter because they want it. This is sometimes called imperative pointing. Within a few months, a different kind of pointing appears. The child points at a dog in the park or an airplane overhead, not because they want it, but because they want you to see it too. This declarative pointing is one of the clearest signs that a child has moved into initiating joint attention. They’re not just responding to your focus; they’re actively trying to create a shared moment.
Other initiating behaviors include holding up a toy to show you (with eye contact), looking back and forth between an interesting object and your face, and eventually combining these gestures with early words.
Why Joint Attention Matters for Language
Multiple longitudinal studies have found that the amount of joint attention between parent and child predicts vocabulary growth. When a baby and caregiver are focused on the same thing at the same time, the words the caregiver says are naturally mapped onto whatever the child is already paying attention to. This makes it far easier for the child to learn what words mean.
Of the two types, responding to joint attention has the stronger correlation with vocabulary development in typically developing children. A baby who reliably follows a parent’s point or gaze gets more of those perfectly timed word-to-object pairings throughout the day. Interestingly, the strength of this relationship appears to decrease over the second year of life, suggesting that joint attention is most important in the earliest stages of learning words, before other learning strategies kick in.
When to Pay Attention to Delays
Because joint attention develops gradually, there’s no single moment when its absence becomes a definitive concern. That said, difficulties with initiating joint attention are one of the earliest and most reliable behavioral markers associated with autism spectrum disorder. One study found that lower levels of initiating joint attention at 8 months predicted the presence of early autism markers at 18 months, explaining over 53% of the variance in risk.
Firm behavioral markers for autism generally become recognizable after the first birthday. By 14 months, some infants showing signs can be reliably identified, and by 18 months, solid markers can be detected in most cases. The American Academy of Pediatrics recommends developmental screening at 9, 18, and 30 months, with specific autism screening at 18 and 24 months.
The behaviors that clinicians look for include whether a child follows a pointed finger to look at something across the room, whether they alternate their gaze between an interesting object and a person’s face, whether they hold objects up to show them (not just hand them over to get help), and whether they use pointing to share interest rather than only to request things. A child who consistently avoids these behaviors past 15 to 18 months warrants a closer look, even if other development seems on track.