Customize the “about” widget in hugo academic them

I am using the hugo-academic theme via RStudio/blogdown to build my webpage. The example page is here: https://themes.gohugo.io/theme/academic/

I would like to add a second list of non-academic Interests below the academic ones. Is this possible?

In the configuration section of about.md there is a section for this list

# List your academic interests.
 [interests]
   interests = [
     "Artificial Intelligence",
     "Computational Linguistics",
     "Information Retrieval"
   ]

but i am not sure how it is passed to the process that actually builds the site. In the spirit of "just add stuff to see if it works" i've tried adding another [other_interests] section but it doesn't seem to do anything.

You can add another list of interests, but the theme doesn't know about the list you added. In the theme's source you'll find this section:

  {{ with $page.Params.interests }}
  <div class="col-sm-5">
    <h3>{{ i18n "interests" | markdownify }}</h3>
    <ul class="ul-interests">
      {{ range .interests }}
      <li>{{ . }}</li>
      {{ end }}
    </ul>
  </div>
  {{ end }}

https://github.com/gcushen/hugo-academic/blob/master/layouts/partials/widgets/about.html#L50-L59

Which renders an HTML section based on a predefined list.
You could try to copy/paste this section and change interests to your other_interests and see how it goes:

  {{ with $page.Params.other_interests }}
  <div class="col-sm-5">
    <h3>{{ i18n "interests" | markdownify }}</h3>
    <ul class="ul-interests">
      {{ range .other_interests }}
      <li>{{ . }}</li>
      {{ end }}
    </ul>
  </div>
  {{ end }}

I suggest reading up on templating in Hugo to get a better understanding of what's happening there. If you have more questions specific to this theme, maybe the source GitHub repository might be a good place to start.