Fig 1.
Theoretical framework for the processing of identity and order information for same-different matching with strings of letters, digits, or symbols.
Stimuli are first encoded via location-specific gaze-centered complex feature detectors. Location-specific complex features then activate location-invariant object identities that are assigned an order in the string. Crucially, we hypothesize the existence of two different location-invariant order-encoding mechanisms: a generic order encoding mechanism, illustrated here by a simple ordinal representation (e.g., R(3), there is the letter R at the 3rd position), and a letter-specific order encoding mechanism (open-bigram coding in the examples shown in the upper-right panel of the Figure (e.g., T-R, there is a T before an R).
Fig 2.
Schematic representation of an experimental trial with an example of a “different” response for transposed-letter stimuli.
Fig 3.
Error rates for each type of stimulus in the transposition and in the substitution conditions when the target string was presented centrally (left panel) and when it was presented displaced two character spaces to the right or left (right panel) in Experiment 1.
Error bars represent within-participant 95% CIs [44].
Fig 4.
d prime values for each type of stimulus in the transposition and in the substitution conditions when the target string was presented centrally (left panel) and when it was presented displaced two character spaces to the right or left (right panel) in Experiment 1.
Error bars represent standard errors.
Fig 5.
Error rates for each type of stimulus in the transposition and in the substitution conditions when the target string was presented with normal spacing (left panel) and when it was presented with an extra space between characters in target stimuli (right panel) in Experiment 2.
Error bars represent within-participant 95% CIs [44].
Fig 6.
d prime values for each type of stimulus in the transposition and in the substitution conditions when the target string was presented with normal spacing (left panel) and when it was presented with an extra space between characters in target stimuli (right panel) in Experiment 2.
Error bars represent standard errors.
Fig 7.
Net transposition costs (in d’ values) as a function of target displacement (Experiment 1, left panel) and inter-character spacing (Experiment 2, right panel) for the three types of stimuli.
Error bars represent standard errors.