Subitising

When we look at a small group of objects, we can often just know how many there are without having to count them all. This is called subitising. Consider a mother cat with her five kittens.  One kitten is removed from the room without the mother cat noticing.  Within seconds, the mother appears agitated, frantically searching the room for her kitten.  It is interesting that animals portray this ability to ‘count’ their offspring.  In fact, the animals are not counting, they are subitising; they have an innate ability to sense a number.  

Children are born with this ability to sense number. At the age of three, a child should be able to subitise 3 objects. By the age of 4, children should be able to subitise a group of 4 objects. However, although the ability to subitise is inherent, we need to make a connection between the number we see and both the word and symbol for that particular set of numbers. We therefore need to count to appreciate what, for instance 3 looks like and then make the connection with the feel that we have for 3. It is therefore important to explore lots of representations and experiences of numbers and their link to the counting word. For this reason, subitising is best developed through experiences and opportunities to make connections as opposed to teaching it explicitly. The majority of children naturally develop the ability to subitise and as adults, we may be subitising without realising it. However, difficulties with subitising is associated with Dyscalculia.

Subitising small numbers is known as Perceptual Subitising. Developing subitising skills for larger numbers aids in visualising numbers and promotes conceptual understanding.

Conceptual Subitising is where we break up smaller numbers that can be perceptually subitised and use our knowledge of numbers to combine them and work out the total. So, conceptual subitising can be used to teach number facts. As the way numbers combine can be different, this exercise can lead to making connections between our number facts.

Some research suggests that we can perceptually subitise 5 or 6 objects, but more recent research is indicating that we perceptually subitise 4 objects and that 5 and 6 are either conceptually subitised as a familiar arrangement or quickly learnt as they are small quantities to combine. What we do know is that dice patterns are easily subitised, so are a useful tool for developing subitising skills. We also know that subitising is integral to the development of number sense.