What does the primacy effect illustrate regarding attention to a set of words?

The primacy effect illustrates that the first word presented often receives full attention, which makes it more likely to be encoded into long-term memory compared to subsequent items on the list. This phenomenon occurs because individuals typically have more cognitive resources available at the beginning of a list, allowing them to focus on and process the initial items more effectively. The first few words are rehearsed more and therefore benefit from better encoding into memory.

The other options do not accurately represent the primacy effect. The suggestion that the last words are remembered better relates to the recency effect, which involves recall of the most recent items. The notion that all words are remembered equally due to repetition disregards the variance in recall performance influenced by their position in a sequence. Lastly, the idea that middle words dominate recall is contrary to both the primacy and recency effects, as it is typically the items at the beginning and end of a list that are more easily remembered.