The serial position effect is a cognitive phenomenon where individuals are more likely to recall the first and last items in a list compared to those in the middle. This effect is divided into the primacy effect and the recency effect. The primacy effect is observed when the initial items in a list are remembered better. This occurs because these items are rehearsed more frequently or receive more elaborative processing, allowing them to be encoded into long-term memory more effectively. For instance, if given a grocery list with items such as milk, eggs, bread, butter, and cheese, people are more likely to remember 'milk' and 'eggs' over 'bread' and 'butter.'

The recency effect, on the other hand, refers to the improved recall of items at the end of a list. This happens because these items are still present in short-term memory when recall is required, making them readily accessible. For example, in the same grocery list, 'cheese' is more likely to be recalled immediately after hearing the list than 'bread' or 'butter.'

Items in the middle of the list suffer from both ends, as they do not benefit from the extensive rehearsal given to the first few items, nor do they remain in short-term memory like the last few items. As new items are added to the list, the ones at the end replace the middle items in short-term memory, making them less likely to be recalled.

Understanding the serial position effect provides valuable insights into the mechanisms of memory. It has practical applications in various fields, including education and marketing, where the positioning of information can significantly impact recall and learning outcomes.