In your toddler's case, there may be times when you think they're ignoring you deliberately, but more often than not, they will just be engrossed in what they're doing and genuinely don't hear you. Your toddler is learning to be able to stop what they're doing and switch their attention to listen and focus on what you are saying. And this is a skill that takes time to master.
A good way to help them switch their attention is to use their name
Many studies have found that specific areas of the brain react when we hear the sound of our own name.[1,2,3] This is a skill that evolves over time and for your toddler now, it means that when they are awake, their brain is learning how to shift attention upon hearing their name and concentrate on something new.
Typically, when they hear their own name and switch their attention, it means they need to be ready for social interaction[2]
This in itself is a complex task.
At the time of hearing their name, your toddler might be playing with a favourite toy or watching TV; for their brain to suddenly switch and be ready to listen to something completely different is quite remarkable. They’re expected to leave their world and become aware of what is happening around them.
There may be times when you need to say their name more than once, or move into their eyesight, so they’re aware you are there. You might also find you need to gently touch their hand or shoulder to attract their attention before you say their name.
Saying their name loudly and firmly is best reserved for when you need their attention in a busy or dangerous place
It can be tempting to shout their name if saying it doesn’t catch their attention straight away. However, think carefully about when you choose to shout to gain their attention; hearing their name being shouted could make them think you only need their attention when you shout. It may also make them think that shouting is the way to get your attention.
Your toddler hears loads of different sounds throughout the day and capturing their attention in a busy place with lots of people, sounds and visual distractions can be that bit trickier. The ability to tune in to other stimuli in a noisy environment is a lifelong skill.[4]
If you have a pet name for them, you might consider keeping this for playful times. In busy or dangerous situations, using their real name, firmly, could help them understand you need their attention. Learning this will take some time so keeping them close to you while they are learning will be safest for them and you.
References:
[1] D.P. Carmody., M. Lewis. (2006) Brain activation when hearing one's own and others' names. Brain Research, Volume 1116, Issue 1.
[2] T. Nakane., M. Miyakoshi., T. Nakai., S. Naganawa. (2016) How the Non-attending Brain Hears Its Owner's Name. Cerebral Cortex, Volume 26, Issue 10, October 2016, Pages 3889–3904.
[3] K.K. Jepson. (2020) Commentary: Learning Students' Given Names Benefits EMI Classes. Frontiers in Psychology.
[4] C.M. Karns, E. Isbell, R.J. Giuliano, H.J. Neville. (2015) Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories. Developmental Cognitive Neuroscience. Volume 13, June 2015, Pages 53-67.