Lecture 8 - Number Cognition Flashcards
What is cardinality?
The number of objects/size of a set. e.g. 4 cats and 4 dogs share the same cardinality.
What is ordinality?
A relational property between sets of different cardinal values. Whether one set is larger/smaller than another in the number of items in the set.
What are arithmetic differences?
Precise ways of moving between numbers of different cardinalities.
What did Piaget show about infants’ understanding of number?
Piaget’s conservation task - Counting alone doesn’t guarantee an understanding of number
What did Starkey, Spelke and Gelman (1990) find about whether infants could habituate to the cardinality of number?
6-9 month-old infants were able to habituate to sets of 3 objects, and then dis-habituate upon seeing sets of 2 objects. All other properties of number were varied in each set, in order to know that the habituation was to the cardinality and nothing else.
Which 3 methods can be used to investigate infants’ understanding of number?
- Habituation tasks
- Violation of expectation
- Choice decision-making
What do all 3 methods into infants’ number cognition tell us?
Infants are sensitive to cardinality, but only up to 4 items. Sums, and habituation cannot be completed if there are more than 4 items.
Describe the sensitivity of infants to sets of numbers larger than 4/5.
At 6 months old, the ratio between two different sets of number needs to be 1:2 to be recognised as different.
At 9 months old, the ratio between sets needs to be around 2:3 for infants to dishabituate.
Required ratios are for infants to approximate differences between the sets.
What did Agrillo, Dadda and Bisazza (2007) find about the number cognition of mosquito fish?
Mosquito fish have a similar number cognition to infants, in that they can distinguish between groups of different sizes if the numbers in the two groups are low enough (below 4/5) or the difference between them is large enough (2:1 ratio).
When do infants use precise number systems vs approximation systems?
Infants use precise number systems at lower numbers, and use approximation systems at higher numbers that cannot be counted.
