Initiating joint attention is when:

Initiating joint attention refers to the process where an individual actively seeks to share an experience or moment with another person, typically by directing their attention towards an object or event while simultaneously engaging the other person. By initiating this bid for attention, the individual may use gestures, eye contact, or vocalizations to encourage the other person to look at or share in the same focus of interest.

This behavior is pivotal in social interactions and communication development, as it helps establish a shared focus and fosters more complex forms of communication. It demonstrates a proactive approach to social engagement, involving both the initiation of interest and the desire for mutual participation in the experience.

The other options focus on various aspects of joint attention but do not accurately encapsulate the idea of initiation. One option describes responding to a bid for attention, which occurs after someone has already made a request for connection. Another option refers to a lack of response, which does not involve the proactive element required for initiation. Lastly, the absence of an opportunity indicates a situation where joint attention cannot occur at all, rather than the action of initiating it.