What effect does increased disparity on stereo models have on the apparent scales?

In stereo models, increased disparity refers to the difference in the position of an object as seen from two different viewpoints—typically the left and right eyes. This disparity plays a crucial role in determining how objects are perceived in three-dimensional space. When the disparity increases, it becomes more pronounced, leading to different interpretations of scale in various directions.

The correct answer highlights that as the disparity between the two viewpoints grows, the difference in the perceived horizontal and vertical scales also becomes more noticeable. Specifically, this means that objects will appear more stretched or compressed in one direction compared to the other; this is particularly relevant in how depth perception is processed. The greater difference between horizontal and vertical scales can impact how a viewer interprets spatial relationships within the model.

The notion that the vertical scale increases could misrepresent the effect, as the vertical perception may not necessarily increase uniformly with disparity. Similarly, a claim that the horizontal scale universally increases isn't accurate, because the key factor here is the relative disparity rather than an absolute increase in scale in either direction. The answer indicating that disparity itself decreases does not align with the understanding that increased disparity means objects are perceived with a larger variation between their horizontal and vertical positions.