Did you notice the article in the July, 2018, ASHA Leader about word finding in older adults? Researchers at the University of Birmingham in the UK found that the higher the older adults’ fitness level, the lower the probability of experiencing a tip of the tongue retrieval (ToT) difficulty. Even accounting for age and vocabulary size, there was a relationship between ToT and aerobic fitness. Here’s the original article: https://www.nature.com/articles/s41598-018-24972-1.
“Word finding difficulties often surface as tip-of-the-tongue experiences. People in a tip-of-the-tongue state have a strong conviction that they know a word, but are unable to produce it” (from the introduction of the above-cited article). Wouldn’t it be interesting to see if there is a similar correlation in children? It wouldn’t surprise me at all!