Right call to action buttons vs left call to action buttons?

Question

I read this interesting article which talks about the Gutenberg principle of a terminal area as being the most appropriate location to place a call to action button to enhance conversions.Simply put

The terminal area is the bottom right area of your home page focal point. It comes from the Gutenberg diagram, an age-old concept developed by Edmund C. Arnold. It’s commonly used to optimize displays that have a limited number of elements. It divides your display into four areas. The primary optical area is at the top left, the strong fallow area at the top right, the weak fallow area at the bottom left, and the terminal area at the bottom right. The user’s eyes naturally begin at the primary optical area and move across and down the display in a series of sweeps to the terminal area.

Though I agree with it from the perspective of most users (lets exclude languages which read from right to left) reading from left to right and right being the final ending zone ,The lack of any A/B testing (in the article) makes me wonder how true this would be.

There is already an existing question on this which gave some good insights but I would like your views on this with regards to the theory posed by this study

Answer 1

When people are not overly barraged with information and the amount of elements on the page (or region) is small, people tend to scan the elements similar to general reading (left to right; top to bottom). With this done, people will click a call to action at the end of the section/information in order to move to the next logical stage of a process.

Compared to general eye-tracking research Nielsen has done (which focuses on a traditional "F" layout of a full webpage), the context of the article appears to focus more on a specific region or when there's a smaller set of elements to consume. Under that context, I'd agree with the general recommendations of the article in that people want to progress after reading everything and thus the logical spot would be the last place they look - the bottom right quadrant. If there's no quadrants (like as I'm typing this answer), then the general bottom works since it's at the conclusion (which is where the "Post your Answer" button is located).

Keep in mind though, this article does not take into context the flow of a form (which the existing question you link to dives into more) nor does it focus on full pages like many eye-tracking studies cover.