The first was the peak of the pain they experienced. If there was a moment in the procedure in which pain suddenly spiked—the doctor’s hand slipping, for example—patients would remember the entire experience as being much more painful overall, regardless of what they reported the rest of the time via the dial.
The peak of an event affects our memory of the event. It is not (just) that the peak stimulus during an event is encoded more deeply. Rather, the peak stimulus dictates our ultimate impression and colors our memory of the entire experience. In other words, if the average pain on the dial is a 5 on a scale of 1 to 10 but the peak pain was 8, our brains remember the whole experience as closer to an 8 than a 5.
Endings matter more
The second element that impacted patients’ memory of the experience was its end. Procedures that ended in pain were remembered as more painful than was actually reported via the dial, and those that ended “not so bad” were remembered as such despite what was reported during. Even if they experienced more objective pain, if the end wasn’t so bad, their memories of the event were far more favorable.
The duo of insights—that the memory of an event is heavily weighted by its peak and its end—is appropriately called the peak-end effect. While its discovery came through exploring pain and discomfort, it’s a stable property of human memory that applies equally to positive experiences.
In the consumer world, this is most often seen in the hospitality industry. Hotels are masters of designing mini-peaks designed for customers’ enjoyment. Hand-stamped toilet paper, towels folded into swans, elaborate lobbies, “surprise” chocolates on pillows, and welcome glasses of champagne are all minor peaks designed to create a fond memory of the hotel stay.
Speakers can also implement the peak-end effect to optimize the impression they leave audiences. Ask yourself, what is my peak? How can I add a positive peak to this story, or this information? And of course - how can I optimize the close and leave them with the most positive impression possible? Introducing these elements can go along way in optimizing for the memory of the speech.