Modes of spatial coding in the Simon task

Interaction mechanism between location and sequence in letter cognition

A previous study used days as a sequence symbol to investigate the interaction mechanism between location and sequence in sequence symbol cognition; the study findings suggested that the spatial stimulus-response compatibility effect and the Simon effect could not co-exist with the SNARC-like effect when processing sequence symbols. The previous study did not include the influence of the difficulty of identifying sequence symbols on the Simon effect in the investigation, so it is unclear whether the conclusion about processing sequence symbols with considerable identification difficulty can be extended to the processing of sequence symbols with less identification difficulty. Therefore, the present study explored letters that have a low level of identification difficulty to investigate the interaction mechanism between location and sequence in sequence symbol cognition. Participants were asked to classify a probe letter, which was randomly displayed on the left or right side of the screen, according to its location (Experiment 1), its sequence (Experiment 2) or its colour (Experiment 3). The results indicated that (1) only the spatial stimulus-response compatibility effect and Simon effect were present in the letter location classification task and letter colour classification task, respectively. (2) The Simon effect co-existed with the SNARC-like effect, and these two effects interacted with each other in the letter sequence classification task. From these results, it can be concluded that the task determines whether the Simon effect and the SNARC-like effect can co-exist, with differences presented across sequence symbols.

Influence of Number Location on the SNARC Effect: Evidence From the Processing of Rotated Traditional Chinese Numerical Words

Studies have widely captured the spatial-numerical association of response codes (SNARC) effect in the processing of various types of numbers in which small numbers are responded to faster with the left hand than with the right hand and larger numbers are responded to faster with the right hand than with the left hand. Although a few studies have explored Arabic numbers to further investigate the influence of number location on the SNARC effect, it remains unclear whether the influence of number location on the SNARC effect is moderated by numerical semantic processing difficulty and the task performed. This study explored traditional Chinese numerical words and rotated them to certain angles, which can increase numerical semantic processing difficulty, to further investigate the influence of the stimulus-response compatibility effect and Simon effect on the SNARC effect in a space classification task (Experiment 1), numerical magnitude classification task (Experiment 2), numerical parity classification task (Experiment 3), and color classification task (Experiment 4). The results indicated that (a) the stimulus-response compatibility effect, not the SNARC effect, prevailed in the numerical space classification task; (b) the SNARC effect, not the Simon effect, prevailed in the numerical magnitude and parity classification task; and (c) the Simon effect and the SNARC effect coexisted in the color classification task. These results suggested that the influence of number location on the SNARC effect was moderated by the task performed. Implications for the theory of the SNARC effect and Simon effect are discussed.

The influence of the location of ordered symbols on the ordinal position effect: The involvement of the task performed

Since the ordinal position effect was identified, several studies have investigated its mechanism in various contexts; however, how the space location of ordinal symbols influences this effect remains unclear. Thus, the present study explored Chinese words representing the day before yesterday, yesterday, tomorrow, and the day after tomorrow as ordinal symbols to investigate how the stimulus space location influences the ordinal position effect across different task contexts. We randomly and equally presented days on the left or right location of a display and asked participants to perform a stimulus space location, a stimulus colour and a stimulus order classification task in three consecutive experiments, respectively. The results revealed that the spatial stimulus-response compatibility effect and Simon effect prevailed in the stimulus space location and colour classification task. Conversely, the ordinal position effect prevailed in the stimulus order classification task. These results suggested that (1) the spatial stimulus-response compatibility effect (or Simon effect) and the ordinal position effect cannot appear simultaneously in some experimental contexts and that (2) the task context predicted which of these effects prevailed. From these results, we conclude that the ordinal symbols could be coded depending on multiple reference frames, including spatial and non-spatial reference frame, and the use of the reference frame was mediated by the task context.