Serial-position effect: A classroom guide for teachers and teacher aides

Serial-position effect – the psychological tendency for humans to remember the first and last items in a list or sequence. Teachers can take advantage of this tendency by presenting the most important information first and last.

When presented with a list of items, people tend to remember the first and last items the most, and the middle items the least.ⁱ This is known as the serial-position effect. If you were shown a list of 20 items, you are probably going to remember the first few items easily. This is called the primacy effect. You will probably be able to recall the last item or 2 as well. This is called the recency effect. The recency effect makes logical sense: more recent items replace old items in your short-term memory and the final items on a list are the most recent to be seen or heard.

It is more likely that students will recall the first and last items delivered in a lesson. This has obvious implications for planning lessons and lesson sequences.

The primacy effect makes less sense however: why does the brain recall the first few items more than the middle items? Assuming that all items have equal importance, there is no rational reason why the brain automatically places more importance on the first items than it does on middle items. If the brain can only remember so many items, why not randomly choose any item? This is what psychologists refer to as a cognitive bias. Our brains have a bias toward remembering the first items on a list for no clear reason.

The serial-position effect has implications well beyond trying to memorise lists of items. It can be applied to the order that teachers introduce content in the classroom. Teachers should carefully consider the order that information is presented to students. For example, if a teacher is introducing a 6-step process to solve a given problem, they can assume that steps 3 or 4 are less likely to be recalled than step 1 or 6. The serial-position effect indicates that step 1 will more easily be recalled due to the primacy effect and step 6 will also be likely to be recalled due to the recency effect. While steps 1 and 6 will be the most recalled, steps 3 and 4 will be more likely to be the least recalled.

The recency effect makes logical sense: more recent items replace old items in your short-term memory and the final items on a list are the most recent to be seen or heard.

Similarly, it is more likely that students will recall the first and last items delivered in a lesson. This has obvious implications for planning lessons and lesson sequences. Take a teacher that intends to introduce 5 new formulas in a single lesson. The lesson is divided equally between the 5 formulas. A week later, students easily recall the first formula due to the primacy effect and have a fair idea about the last formula. If the teacher is aware of the serial-position effect, they should ensure that the first and last formulas introduced are the most important ones if possible. Bear in mind that this is a broad generalisation – some students may remember every formula while others may remember nothing at all. Some may even remember the middle formulas. The serial-positioning effect is not a fool-proof predictor of what will be recalled and what will be forgotten, but it does give teachers something to consider when planning programs, lessons, activities and presentations.

Hint: marketers take advantage of the serial-positioning effect. The first and last words in a radio or TV ad are more easily remembered. Online shopping sites display the more profitable items first. On a list of product benefits, the items that marketers want customers to recall the most are placed first and last.

Foot notes:

1. Feigenbaum, E., Simon, H. (1962). A theory of the serial position effect. British Journal of Psychology, 53(3), 307-320.