When does an infant normally begin to express anger?

Infants typically begin to express anger around 4 to 6 months of age. At this stage, they may show signs of frustration or anger through crying, fussing, or physical reactions when their needs are not met or when they are frustrated. As they grow and develop, their ability to express emotions becomes more nuanced. By around 12 months, they may also exhibit anger through more complex behaviors, such as tantrums.