Yes, valleys – plural. Typically the uncanny valley refers to visual cues. But as we move into emulsional worlds and bring along the other four senses, we begin to realize that there are multiple uncanny valleys, and they all influence each other.
Many studies over the years show that sound influences human perception of picture and vice versa. This means that as you begin to create an emulsional world, you need to worry about not one uncanny valley, but up to five (one for each sense). If the synthetic experience involves sight, sound and touch, each sense will have its own uncanny valley, and it will influence the other – they are in a dynamic equilibrium that will shift as the content (and interaction) changes.
To make things even more complicated, each uncanny valley has multiple factors embedded within it – behavior, cultural, technical, and contextual parameters. These end up being highly user-specific, so that can shift the curve as well.
And to make things even more complicated, different generations have different tolerances for uncanniness. One could argue that the current teens are much more accepting of virtual characters and environments that older people would find “creepy.” That said, I believe that since they are still analog/human, the valleys will persist. It is just that the curves will move along the axes over time.
But in reality:
And they all influence each other. So for digital to approach the “gold standard” of physical reality by adding in senses, it becomes a much more fluid target.
This is one reason I’m a fan of virtual targeting “unnatural worlds.” In that case, the uncanny valley becomes largely moot, though then there will likely be canny valleys to deal with (sorry, don’t know what those look like yet).