The Simon effect of spatial words in eye movements: Comparison of vertical and horizontal effects and of eye and finger responses

Abstract

Spatial stimulus location information impacts on saccades: Pro-saccades (saccades towards a stimulus location) are faster than anti-saccades (saccades away from the stimulus). This is true even when the spatial location is irrelevant for the choice of the correct response (Simon effect). The results are usually ascribed to spatial sensorimotor coupling. However, with finger responses Simon effects can be observed with irrelevant spatial word meaning, too. Here we tested whether a Simon effect of spatial word meaning in saccades could be observed for words with vertical ("above" or "below") and horizontal ("left" or "right") meanings. We asked our participants to make saccades towards one of the two saccade targets depending on the color of the centrally presented spatial word, while ignoring their spatial meaning (Experiment 1 and 2a). Results are compared to a condition in which finger responses instead of saccades were required (Experiment 2b). In addition to response latency we compared the time course of vertical and horizontal effects. We found the Simon effects due to irrelevant spatial meaning of the words in both saccades and finger responses. The time course investigations revealed different patterns for vertical and horizontal effects in saccades, indicating that distinct processes may be involved in the two types of Simon effects.

Enhanced spatial stimulus–response mapping near the hands: The Simon effect is modulated by hand-stimulus proximity.

“…Researchers suggested that the sensorimotor representation evoked by location words influences the motor response, eventually resulting in a semantic Simon effect (Khalid & Ansorge, 2013). The semantic Simon effect in Exper iment 4 is consistent with the embodied cognition view.…”

“…The Simon effect refers to the fact that responses to compatible stimuli (i.e., the stimuli are ipsilateral to the response) are faster and more accurate than responses to incompatible stimuli (i.e., the stimuli are contralateral to the response), while stimulus location is irrel evant to the task. Recently, many studies have used location words (e.g., left or right) to produce the semantic Simon effect (Khalid & Ansorge, 2013;Pellicano, Lugli, Baroni, & Nicoletti, 2009). In the semantic Simon task, location words are presented at the center of a display, and participants are told to respond to a feature of the word, such as color, while ignoring its meaning.…”

Behavioral and neural interaction between spatial inhibition of return and the Simon effect

“…The ocular-motor theory of IOR emphasizes the correlation between IOR and oculomotor system: the peripheral cue produces an automatic activation of an eye movement to that location, which generates IOR (Rafal et al, 1989; Kingstone and Pratt, 1999; Klein, 2000). And, both spatial IOR and the Simon effect could be influenced by eye movements (Abrahamse and Van der Lubbe, 2008; Buetti and Kerzel, 2010; Khalid and Ansorge, 2013). In the present study, in order to minimize the effects of eye movements, we instructed the participants to fixate at the central box throughout the experiment.…”

Remember down, look down, read up: Does a word modulate eye trajectory away from remembered location?

“…Secondly, our results indicate that merely an activation of a part of space by a word makes the memorized object in the space more tangible, which is evident by eye curvatures. Thirdly, it appears that meaning-location compatibility (e.g., Khalid and Ansorge 2013) or the location-saccade direction compatibility (Theeuwes et al 2005) effects should not be generalized over all spatial directions but rather tested separately.…”

“…For instance, previous research suggests that participants make faster saccades to the word sun, when located in the upper part of the screen compared to the lower part (Dudschig et al 2013). Moreover, it seems that even when irrelevant to the task, word meaning can influence the time of saccade initiation: Saccades were faster when their direction (left/ right, above/below) from the centrally presented word (left/ right, above/below) were compatible than when they were incompatible (Khalid and Ansorge 2013).…”