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... 16 (high contrast) their threshold. 2.1.3. Determining contrast detection thresholds Thresholds were determined using staircase procedures that followed a 2-down, 1-up rule (71% detection threshold; =-=Macmillan & Creelman, 1991-=-). Participants indicated in which of two prespecified time intervals (200 ms each) a target Gabor was presented (left button for first interval, right button for second interval). Stimulus contrast w...

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...ecent study (Born & Kerzel, 2008), we looked at the impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (=-=Findlay & Walker, 1999-=-; Godijn & Theeuwes, 2002; Kopecz, 1995; Leach & Carpenter, 2001; Munoz & Fecteau, 2002; Trappenberg, Dorris, Munoz, & Klein, 2001). They assume that target- and distractor-related signals mutually in...

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... with central distractors may be that prior to target onset, activity is focused at the central location in a top-down manner to maintain fixation as instructed (Findlay & Walker, 1999; Kopecz, 1995; =-=Munoz & Wurtz, 1993-=-). The distractor stimulus may therefore not be able to increment fixational activity any further. Fourth, although the relative shifts in optimal SOA across contrast conditions were in line with our ...

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...odels suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; Godijn & Theeuwes, 2002; Kopecz, 1995; Leach & Carpenter, 2001; Munoz & Fecteau, 2002; =-=Trappenberg, Dorris, Munoz, & Klein, 2001-=-). They assume that target- and distractor-related signals mutually inhibit each other and because of the inhibitory influence of the distractor on the target, saccadic latencies are prolonged. From t...

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...el, 2008), we looked at the impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; =-=Godijn & Theeuwes, 2002-=-; Kopecz, 1995; Leach & Carpenter, 2001; Munoz & Fecteau, 2002; Trappenberg, Dorris, Munoz, & Klein, 2001). They assume that target- and distractor-related signals mutually inhibit each other and beca...

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...r effect (RDE) denotes the finding that saccadic eye movements towards a visual target are delayed if a distractor stimulus is presented simultaneously with and at a certain distance from the target (=-=Walker, Deubel, Schneider, & Findlay, 1997-=-; Walker, Kentridge, & Findlay, 1995). In a recent study (Born & Kerzel, 2008), we looked at the impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from com...

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...aced by a barely visible distractor. This may have triggered a partial release from fixation. It is well known that the offset of the fixation stimulus prior to target onset reduces saccadic latency (=-=Saslow, 1967-=-) which may partly be attributed to oculomotor release from fixation (Findlay & Walker, 1999; Kingstone & Klein, 1993; Reuter-Lorenz, Hughes, & Fendrich, 1991; Rolfs & Vitu, 2007). The fixation releas...

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...nown that the offset of the fixation stimulus prior to target onset reduces saccadic latency (Saslow, 1967) which may partly be attributed to oculomotor release from fixation (Findlay & Walker, 1999; =-=Kingstone & Klein, 1993-=-; Reuter-Lorenz, Hughes, & Fendrich, 1991; Rolfs & Vitu, 2007). The fixation release component may have been stronger than the distractor effect und thus, RDE at negative SOAs were precluded. Experime...

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...he impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; Godijn & Theeuwes, 2002; =-=Kopecz, 1995-=-; Leach & Carpenter, 2001; Munoz & Fecteau, 2002; Trappenberg, Dorris, Munoz, & Klein, 2001). They assume that target- and distractor-related signals mutually inhibit each other and because of the inh...

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...ned by warning effects: When the distractor preceded the target, it may have alerted participants to the upcoming target appearance, especially with high-contrast distractors (Findlay & Walker, 1999; =-=Ross & Ross, 1980-=-, 1981; Walker et al., 1995). In the low-contrast distractor conditions, facilitation may additionally occur through a fixation release component. Recall, that we extinguished the fixation stimulus up...

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...he fixation stimulus prior to target onset reduces saccadic latency (Saslow, 1967) which may partly be attributed to oculomotor release from fixation (Findlay & Walker, 1999; Kingstone & Klein, 1993; =-=Reuter-Lorenz, Hughes, & Fendrich, 1991-=-; Rolfs & Vitu, 2007). The fixation release component may have been stronger than the distractor effect und thus, RDE at negative SOAs were precluded. Experiment 2 tried to clarify the role of a fixat...

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...stimulus properties (such as contrast) should influence the corresponding signal in some way. It is well known that high-contrast targets produce shorter saccadic latencies than low-contrast targets (=-=Carpenter, 2004-=-; Doma & Hallett, 1988a, 1988b; Ludwig, Gilchrist, & ⇑ Corresponding author. Address: Faculté de Psychologie et des Sciences de l’Éducation, Université de Genève, 40 Boulevard du Pont d’Arve, 1205 Gen...

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...rast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; Godijn & Theeuwes, 2002; Kopecz, 1995; Leach & Carpenter, 2001; =-=Munoz & Fecteau, 2002-=-; Trappenberg, Dorris, Munoz, & Klein, 2001). They assume that target- and distractor-related signals mutually inhibit each other and because of the inhibitory influence of the distractor on the targe...

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...adic eye movements towards a visual target are delayed if a distractor stimulus is presented simultaneously with and at a certain distance from the target (Walker, Deubel, Schneider, & Findlay, 1997; =-=Walker, Kentridge, & Findlay, 1995-=-). In a recent study (Born & Kerzel, 2008), we looked at the impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor...

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...; Pannasch, Dornhoefer, Unema, & Velichkovsky, 2001). The notion fits also well with neurophysiological data suggesting that distractors produce a sharp and transient drop in target-related activity (=-=Dorris, Olivier, & Munoz, 2007-=-). Furthermore, distractor properties such as contrast may determine the maximal strength of the disruption (see Fig. 8B). The account as illustrated in Fig. 8 is highly speculative and probably overs...

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...arget and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; Godijn & Theeuwes, 2002; Kopecz, 1995; =-=Leach & Carpenter, 2001-=-; Munoz & Fecteau, 2002; Trappenberg, Dorris, Munoz, & Klein, 2001). They assume that target- and distractor-related signals mutually inhibit each other and because of the inhibitory influence of the ...

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... similar general ‘‘interrupt’’ signal caused by the onset of a new visual event has already been proposed by Reingold & Stampe (2002; see also Buonocore & McIntosh, 2008; Kerzel, Born, & Souto, 2010; =-=Pannasch, Dornhoefer, Unema, & Velichkovsky, 2001-=-). The notion fits also well with neurophysiological data suggesting that distractors produce a sharp and transient drop in target-related activity (Dorris, Olivier, & Munoz, 2007). Furthermore, distr...

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... was a peak in the RDE at 0 ms SOA, presenting the distractor slightly after the target (up to 40–80 ms) still produced distractor effects, whereas there was a sharp drop with negative SOAs (see also =-=Buonocore & McIntosh, 2008-=-). To this point, one may only speculate why distractors may be more disruptive when presented after the target. However, the finding may be taken to argue against a simple and smooth lateral inhibito...

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...t reduces saccadic latency (Saslow, 1967) which may partly be attributed to oculomotor release from fixation (Findlay & Walker, 1999; Kingstone & Klein, 1993; Reuter-Lorenz, Hughes, & Fendrich, 1991; =-=Rolfs & Vitu, 2007-=-). The fixation release component may have been stronger than the distractor effect und thus, RDE at negative SOAs were precluded. Experiment 2 tried to clarify the role of a fixation release componen...

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...es (such as contrast) should influence the corresponding signal in some way. It is well known that high-contrast targets produce shorter saccadic latencies than low-contrast targets (Carpenter, 2004; =-=Doma & Hallett, 1988-=-a, 1988b; Ludwig, Gilchrist, & ⇑ Corresponding author. Address: Faculté de Psychologie et des Sciences de l’Éducation, Université de Genève, 40 Boulevard du Pont d’Arve, 1205 Genève, Switzerland. Fax:...

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...f a distractor stimulus is presented simultaneously with and at a certain distance from the target (Walker, Deubel, Schneider, & Findlay, 1997; Walker, Kentridge, & Findlay, 1995). In a recent study (=-=Born & Kerzel, 2008-=-), we looked at the impact of target and distractor contrast on the RDE. Most models suggest that the effect stems from competitive processes in the oculomotor system (Findlay & Walker, 1999; Godijn &...

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...es (such as contrast) should influence the corresponding signal in some way. It is well known that high-contrast targets produce shorter saccadic latencies than low-contrast targets (Carpenter, 2004; =-=Doma & Hallett, 1988-=-a, 1988b; Ludwig, Gilchrist, & ⇑ Corresponding author. Address: Faculté de Psychologie et des Sciences de l’Éducation, Université de Genève, 40 Boulevard du Pont d’Arve, 1205 Genève, Switzerland. Fax:...

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...ly equal modulations of the RDE. Alternatively, modulations of the RDE due to target properties such as contrast may be more strongly attenuated through top-down influences on the target signals (see =-=Born & Kerzel, 2009-=-). Note that the saccades in our experiments were not necessarily purely stimulus-driven. Observers followed the experimental instructions to saccade to the peripheral stimulus as fast as possible. Th...

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...r first study (Born & Kerzel, 2008) also holds: RDEmax increased with increasing distractor contrast, suggesting that a stronger signal perturbed saccade programming more than a weak signal (see also =-=Bompas & Sumner, 2009-=-b). RDEmax was less influenced by target contrast: The slowing due to the distractor was not weaker when the target signal was strong. This may be explained by considering that distractor contrast inf...

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...r first study (Born & Kerzel, 2008) also holds: RDEmax increased with increasing distractor contrast, suggesting that a stronger signal perturbed saccade programming more than a weak signal (see also =-=Bompas & Sumner, 2009-=-b). RDEmax was less influenced by target contrast: The slowing due to the distractor was not weaker when the target signal was strong. This may be explained by considering that distractor contrast inf...

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...t be disrupted as strongly. A similar general ‘‘interrupt’’ signal caused by the onset of a new visual event has already been proposed by Reingold & Stampe (2002; see also Buonocore & McIntosh, 2008; =-=Kerzel, Born, & Souto, 2010-=-; Pannasch, Dornhoefer, Unema, & Velichkovsky, 2001). The notion fits also well with neurophysiological data suggesting that distractors produce a sharp and transient drop in target-related activity (...