Drawing is rarely present in children younger than 2-2.5 years old (Piaget, 1962). Before about age 4, children draw scribbles. At first they are just scribbles, then they evolve into different types of scribbles to represent different things. By age 4 they are drawing recognizable shapes. Drawings begin with circles, ellipses and lines. Minimal features overlap where they’re supposed to and occur in roughly the right places. Proportions, perspective and complex arrangements of parts are all missing at this point. A person may be drawn as a head with arms and legs sticking out of the head. Drawings of a model will not necessarily include the same number of objects as in the model. Water in a jar is drawn as a scribble floating in the jar. Trees on a hillside may be lying down parallel to the side of the hill, and houses may be sitting any which way (even on their sides!).
Around age 4, children begin to draw angles, and then straight sided figures. At first their triangles and squares all have the same number of sides, but this soon changes. Water in a jar will be represented by a line, but it won’t necessarily be horizontal. In drawing a three-dimensional model, the number of drawn objects will be correct, but they will all be lined up along the bottom edge of the paper in pairs or small clumps, (not necessarily in the right order left to right). Children will say that they can’t put things on the paper as they should be because the objects in behind would have to be drawn piercing the paper (they are unable to draw them overlapping).
Once children are able to draw something reasonably accurately, they begin to draw with an exaggerated realism. They may draw things at all different angles in order to show features not visible from just one viewpoint (e.g. top view of a cart, but side view of the wheels). They may draw the contents of a person’s stomach, or roots buried underground. Trees and people are drawn perpendicular to the side of a hill, rather than standing upright. They draw railroad tracks as parallel lines rather than receding lines, since the ties are the same size all the way down. In other words, they draw what they know is there, rather than what is actually seen from a given perspective.
Towards the end of the representational (preoperational) period, children will often draw train tracks in parallel, but choose a drawing with tracks in perspective. In addition, trees, and houses are sometimes drawn somewhat vertically rather than always perpendicular to the side of a hill, and they will put trees on a plasticine model vertically rather than perpendicularly.
By age 7-8, children can draw complex geometric figures accurately, returning to a reference point to keep track of what they are drawing if they need to. They are able to generate a mental image and work from that instead of copying what they are drawing bit by bit.
Drawings reflect a shift from intellectual realism (what is there) to visual realism (what can be seen from a particular point of view). For example a cart is now drawn in side view with only two wheels visible (or in top view with no wheels visible). Perspective improves but still needs some work. Trees and houses are drawn vertically and water levels are drawn horizontally, but initially only after some trial and error. Railroads are drawn straight and parallel in the foreground, then changing to converging lines in the background. In drawing a model village, children are able to get objects in the right places relative to each other (both left-right and before-behind); but underestimate the before-behind distances (they are still half-way in a straight line). Distances are reduced to scale, but the objects aren’t, which makes the drawings somewhat crowded. And if an object is moved after having being drawn in, the child has problems putting it in its new location in the drawing.
Linear Logical Art
Late Childhood (partway through the concrete operational period)
Perspective is systematic by age 8-9. Objects on a hill are consistently drawn vertically rather than perpendicular to the hill. Water levels in a jar are drawn consistently horizontal. Railroad tracks recede continuously into the background, with the angle of tracks, size and spacing of ties, and size of trees all showing correct perspective. In drawing a model village, spatial relations, distances and proportions are all accurate.
Adolescence (formal operations)
Adolescents spontaneously choose to draw a diagram rather than a picture of a model village. The perspective is overhead like a map. Houses are represented by squares and rectangles and trees represented by circles. Distances and locations are accurate and possibly even measured systematically using a ruler and a grid.
Source: Piaget, Jean, and Bärbel Inhelder, 1956. The Child’s Conception of Space. Translated from the French by F.J. Langdon & J.L. Lunzer. Humanities Press, NY.