In which stage of development is a child likely to believe that two glasses containing the same volume of liquid are equal, regardless of their shape?

The concrete operational stage is accurately associated with the cognitive abilities of children aged roughly 7 to 11 years. During this stage, children develop the ability to think logically about concrete events. They also become capable of understanding the concept of conservation, which refers to the understanding that certain properties of objects, such as volume, remain constant even when their form or shape changes.

In the context of the question, a child in the concrete operational stage would be able to recognize that two glasses of the same volume of liquid can still be equal in amount even if one glass is taller and thinner while the other is shorter and wider. This reflects their newfound ability to consider multiple aspects of a situation and apply logical thinking to reach conclusions about physical properties, showing that they understood conservation of liquid in varying shapes.

Other stages do not possess this ability. For instance, in earlier developmental stages, children might focus on superficial appearances rather than the underlying principles of volume, which is why this ability emerges specifically during the concrete operational stage.