A similar correspondence effect occurs between the size of a stimulus and the left/right response. When presented with large and small stimuli, the left response was numerically faster than the right response, but only the latter was more accurate. Interestingly, these results also held true for two different sets of stimulus, suggesting that the size of a physical stimulus plays a role in categorization. Ultimately, this means that we are able to make a judgment about an object based on its size, shape, and color.
The correspondence effect has several explanations. One is the ATOM. The ATOM claims to have a generalized magnitude processing system that processes information about magnitudes. This processing mechanism requires the retina to receive information about magnitudes, time, and space. However, it is not clear whether this effect is causal or just a result of the human brain’s structure. Nevertheless, the findings are a strong indication that this effect exists and has a role in understanding the human brain’s visual system.
Another explanation is the perceptual constancy. This constancy is a phenomenon that allows a person to make an accurate judgment about a shape, regardless of whether it is face-on or slanted. For example, the door could be half-opened and a trapezoid shape would show up on the retina. The distal stimulus would therefore be a rectangular door. Another example of constancy is lightness.
Moreover, the percept can involve a single or multiple senses. Hence, a single stimulus may be interpreted as a vase and two faces as two separate faces. The same stimulus can be perceived as two different objects depending on the recipient’s memory and prior experiences. Likewise, the same stimuli can produce different percepts depending on culture and context. The same stimulus may affect perception in different cultures and different ages.