“What light through yonder window breaks? It is the east, and Juliet is the sun.”

Was Shakespeare implying that Juliet was massive, orange and gaseous when he wrote this? Of course not. He was drawing an analogy with the sun to illustrate the figurative warmth that Romeo draws from loving Juliet.

Helping students to understand analogies is important. Not just English-exam important, but even bigger than that.

Analogical reasoning is fundamental to learning. That’s according to Dedre Gentner, Alice Gabrielle Twight professor of psychology and professor of education at Northwestern University, near Chicago.

The interplay between analogical reasoning and language is “what makes us so smart as a species,” she has written, “and what makes children such rapid learners”.

Gentner - whose 40 years of research on analogy’s role in human cognition has earned her an American Psychological Association Award for Distinguished Scientific Contributions, among others - defines analogy as a “device for conveying that two situations or domains share relational structure despite arbitrary degrees of difference in the objects that make up the domains”.

In some processes, such as navigation, humans are “really no great shakes” in comparison with other animals, she says. When it comes to memory, for example, researchers have shown that a Clark’s nutcracker bird can recall up to 20,000 locations where it has hidden nuts. Humans can’t do anything like that.

“But in analogical reasoning and relational abstraction, we’re unbelievable,” Gentner says. “This is important for all kinds of things, but in particular for learning.”

In illustrating the importance of analogical processes in learning, Gentner talks about how an analogy with the solar system was historically used to understand what happens inside an atom, where electrons orbit a nucleus (both are central force systems).

When you’re dealing with a 20-year-old, you can explain what a central force system is in words, Gentner continues. But even much simpler relational concepts, such as symmetry, are hard to explain verbally to young children.

“To a two-year-old, or a five-year-old, or an eight-year-old, it’s very hard to explain relational abstractions purely verbally because they don’t have the vocabulary and the conceptual understanding [at that age] to even understand the explanation,” she says.

Analogy shows us common structures, teaches us about abstract concepts and helps us to retain that information, especially if the abstract relational structure is given a name, Gentner explains.

In one study that Gentner co-authored, three-year-olds were given an example of visual symmetry: either a picture of three cats with a larger cat in the middle or a picture of three cows with a larger one in the middle. In both cases, they were told that the picture showed a “toma”. Then the children were shown a picture of three elephants with a larger one in the middle alongside a picture of a squirrel, a cat and a cow, and were asked which of these was also a toma. When the children responded, 98 per cent of their responses were for the “object match” (the squirrel, cat and cow image) rather than the “relational match” (the three elephants).

But then the children were given both the three-cat and three-cow pictures, told they were both “tomas” and asked: “Can you see why they’re both tomas?” - a question designed to encourage comparison.

Next, they were shown again the picture of three elephants alongside the picture of the squirrel, cat and cow, and asked, “Which of these is also a toma?” After that, 57 per cent of children chose the relational match.

The study shows that comparing structures “can reveal things that you simply didn’t see” when the examples are looked at on their own, Gentner explains.

“Relational structure in lots and lots of cases isn’t obvious,” she says. “You say ‘carnivore’ to a kid, they are going to think essentially you mean a tiger, if that’s what you’re pointing to.” But if you get them to compare a tiger, a shark, a lion and a wolf, “the kid will eventually be able to see it, to get this abstract principle that [a carnivore] is anything that eats animals”.

How teachers can use analogies

Gentner also emphasises the learning we gain from “alignable differences” within analogies: where comparisons highlight important differences between relational structures. A study led by Gentner in the Chicago Children’s Museum used an experiment in which children of different ages were asked to build model skyscrapers. The experiment showed the power of analogical comparison to reveal key differences, in this case, the importance of diagonal braces in construction.

In the study, some children were first shown two models side by side, one with a diagonal brace and one without such a brace, and encouraged to wiggle them to test their stability. The seven- and eight-year-old children given highly similar (and therefore easily aligned) models fared significantly better in building more stable models than children given less clear comparisons or no training at all. However, younger children couldn’t grasp the importance of diagonal braces even with the analogical comparison training.

The study showed that “if you’re 7 or 8, you learn a lot - without anyone telling you ‘that’s a diagonal, it’s very important’ - just by comparing two things and seeing this thing pop out at you as what made the difference”, says Gentner. “Good news: comparison is a very powerful learning mechanism. Bad news: it needs a lot of support for very young kids.”

But can analogical reasoning be taught to everyone? Are some people better at it than others? Gentner proposes that while “people do vary”, she thinks “infants start with some ability to do this”.

“I believe, and this is controversial, that we can increase that ability,” she says. “I think kids can basically appreciate analogy more if they get practice at that, and if parents and teachers encourage thinking analogically.”

In terms of how analogical reasoning can be encouraged, Gentner emphasises the concept of “progressive alignment” : starting with analogies that use very concrete matches before moving on to more abstract ones. “I would encourage teachers to use progressive alignment: to compare lion to tiger before they get all the way to shark, for example, in teaching what a carnivore is,” she says.

Another key area is understanding the way language and analogy interact, as in the “toma” study. “If you name two things by the same name, kids become really curious about what’s alike about them,” says Gentner. “It works much better with little kids than saying ‘See how similar these are? See how these are alike?’”

She suggests that we should “teach analogies in a very explicit way, don’t just throw them out”. Teachers could “put them on the blackboard, draw the lines between them, encourage the kids to draw the lines … to think about what the two things have in common”.

If teachers can take this explicit approach, it can have real benefits for students, Gentner explains. “Take analogy seriously and really use it,” she advises. “It’s such a powerful way of learning.”

John Morgan is a freelance journalist

This article originally appeared in the 26 February 2021 issue under the headline “Tes focus on… Analogical reasoning”