What does "veridicality" mean in terms of psychology?

Question

I'm reading the paper "Visual Space Perception and Visually Directed Action" by Loomis, Da Silva, Fujita and Fukusima (1992; pdf). In this paper, the word 'veridicality' is used in several sentences.

Some examples:

• Even with such a narrowed focus, it is apparent that no consensus on the veridicality of visual space perception exists, for the experimental results depend strongly on both the criterion of veridicality and the psychophysical method used.

• One criterion for veridicality is linearity of the function relating perceived egocentric distance to physical distance.

I used dictionaries and websites (including Wikipedia) to get a grasp of this concept, however, I found nothing that gave good meaning to this word. I assume this is a psychological term, since the linguistic meaning didn't fit well in my opinion.

What does 'veridicality' mean, and how I should interpret it in this context?

References
Loomis JM, da Silva JA, Fujita N, Fukusima SS. (1992) Visual space perception and visually directed action. Journal of experimental psychology: Human perception and performance 18(4), 906-921.

Answer 1

Veridicality is a term used in cognitive science; it is the degree to which your internal representation of the world accurately reflects the external world.

Some background

Since the work on Humberto Maturana in color perception, it was considered very important to not always focus on the fact that there is some external stimuli to be cognized by the subject and then reacted on, but that instead there is an internal world or representation which is then cognized and responded to. In many cases the veridicality of the internal representation is very good, and the experimenter can focus on just the easy-to-observe external stimuli. However, in many settings (like color perception) the veridicality of the internal representation is low (easiest way to imagine this: think of a difference in internal representation between a color-blind and non-color-blind person). Hence the experimenter needs to explicitly measure the internal representation and try to understand how it acts. Once you have a measure of this (a 'criterion for veridicality') then you can start to think about how the subject cognizes the stimuli.

Specific to this paper

In the context of the first sentence, what the authors are saying is: even with the narrow focus, it appears that the accuracy of the internal representation does not improve. Thus, the experimental results depend not only on the external stimuli (psychophysical method used) but how good we are at estimating the accuracy of the internal representation (criterion of veridicality).

In the second sentence they propose a metric of veridicality: ask how far you think an object is (say in meters) if the results scale linearly with actual distance, then the internal representation of space is good, else it is not.