Foundation: Classification

At around eight months of age, children distinguish between familiar and unfamiliar people, places, and objects, and explore the differences between them. (Barrera and Mauer 1981)

At around 18 months of age, children show awareness when objects are in some way connected to each other, match two objects that are the same, and separate a pile of objects into two groups based on one attribute. (Mandler and McDonough 1998)

At around 36 months of age, children group objects into multiple piles based on one attribute at a time, put things that are similar but not identical into one group, and may label each grouping, even though sometimes these labels are overgeneralized. (36 mos.; Mandler and McDonough 1993)

For example, the child may:

• Explore how one toy feels and then explore how another toy feels.

• Stare at an unfamiliar person and move toward a familiar person.

For example, the child may:

• Look at the crayons before choosing a color. (12–18 mos.; Parks 2004, 77)

• Choose usually to play with the blue ball even though there is a red one just like it. (12–18 mos.; Parks 2004, 77)

• Pick the toy car from the bin filled with toy dishes. (15–18 mos.; Parks 2004; 77)

• Pack the baby doll’s blanket, brush, bottle, and clothes into a backpack. (15–19 mos.; Parks 2004, 77)

• Match two identical toys; for example, find another fire truck when the infant care teacher asks, “Can you find a truck just like that one?” (15–19 mos.; Parks 2004; 77)

• Place all toy cars on one side of the rug and all blocks on the other side. (15–18 mos.; Parks 2004, 77)

For example, the child may:

• Identify a few colors when they are named; for example, get a red ball from the bin of multicolored balls when the infant care teacher asks for the red one. (Scaled score of 10 for 34:16–36:15 mos.; Bayley 2006, 97; 33 mos.+; Parks 2004, 79)

• Make three piles of tangrams in various shapes, such as a circle, square, and triangle. (30–36 mos.; Parks 2004, 79)

• Pick two big bears from a bowl containing two big bears and two small bears, even if the big bears are different colors. (Scaled score of 10 for 30:16–33:15 mos.; Bayley 2006, 74)

• Sort primary-colored blocks into three piles: a red pile, a yellow pile, and a blue one. (33 mos.+; Parks 2004, 79; 32 mos.; Bayley 2006)

• Point to different pictures of houses in a book even though all of the houses look different. (30–36 mos.; Parks 2004, 79)

• Put all the soft stuffed animals in one pile and all the hard plastic toy animals in another pile and label the piles “soft animals” and “hard animals.” (18–36 mos.; Lally and others 1995, 78–79)

• Call all four-legged animals at the farm “cows,” even though some are actually sheep and others horses. (18–36 mos.; Lally and others 1995, 78–79)

Behaviors leading up to the foundation (4 to 7 months)

During this period, the child may:

• Explore toys with hands and mouth. (3–6 mos.; Parks 2004, 10)

• Bang a toy on the table. (5.5–7 mos.; Parks 2004, 25)

• Touch different objects (e.g., hard or soft) differently.

Behaviors leading up to the foundation (9 to 17 months)

During this period, the child may:

• Roll a car back and forth on the floor, then roll a ball. (6–11 mos.; Parks 2004, 26)

• Use two items that go together; for example, brush a doll’s hair with a brush, put a spoon in a bowl, or use a hammer to pound an object. (9–15 mos.; Parks 2004, 26–27; by 12 mos.; American Academy of Pediatrics 2004, 243)

• Put the red blocks together when the infant care teacher asks, “Which blocks go together?”

Behaviors leading up to the foundation (19 to 35 months)

During this period, the child may:

• Point to or indicate the realistic-looking plastic cow when the infant care teacher holds up a few toy animals and says, “Who says, ‘moo’?” (18–22 mos.; Parks 2004; 85)

• Sort three different kinds of toys; for example, put the puzzle pieces in the puzzle box, the blocks in the block bin, and the toy animals in the basket during clean-up time. (19–24 mos.; Parks 2004, 77)

• Show understanding of what familiar objects are supposed to be used for, such as knowing that a hat is for wearing or a tricycle is for riding. (Scaled score of 10 for 23:16–25:15 mos.; Bayley 2006, 93)

• Pick a matching card from a pile of cards. (Scaled score of 10 for 24:16–25:15 mos.; Bayley 2006, 70)

• Point to or indicate all the green cups at the lunch table. (26 mos.; Bayley 2006)

• Call the big animals “mama” and the small animals “baby.” (27 mos.; Bayley 2006)

• Help the infant care teacher sort laundry into two piles: whites and colors. (28 mos.; Hart and Risley 1999, 95)

• Put the red marker back in the red can, the blue marker back in the blue can, and the yellow marker back in the yellow can when finished coloring. (Scaled score of 10 for 26:16–28:15 mos.; Bayley 2006, 71)

• Match one shape to another shape. (26–29 mos.; Parks 2004, 78; 26–30 mos.; Parks 2004)