Within the content section of the Product Recommendation, select the Product Recommendation Settings. If you go to the Content of Recommendations section there is an algorithm dropdown.
This can be accessed from the following breadcrumb trail:
Inactive/Active Campaigns -> Product Recommendation Campaign -> Content -> Product Recommendation Variation -> Recommendation Settings
By default, this is set to Adaptive which uses machine learning to tailor the recommendations automatically to the page on which they reside.
The algorithm choice on specific page Recommendations can improve ROI based on the context of the page. To see a full list of Bunting Product recommendation algorithms and what they do please follow this link.