Different effects of the two types of spatial pre-cueing: what precisely is “attention” in Di Lollo’s and Enns’ substitution masking theory?

Abstract

Enns and Di Lollo [Psychological Science, 8 (2), 135-139, 1997] have introduced the object substitution theory of visual masking. Object substitution masking occurs when focusing attention on the target is delayed. However, Posner (Quarterly Journal of Experimental Psychology, 32, 3-25, 1980) has already shown that attention can be directed to a target at least in two ways: intentionally (endogenously) and automatically (exogenously). We conducted two experiments to explore the effects of endogenous and exogenous cues on substitution masking. The results showed that when attention was shifted to the target location automatically (using a local peripheral pre-cue), masking was attenuated. A decrease in target identification dependent on a delay of mask offset, typical to substitution masking, was not observed. However, strong substitution masking occurred when the target location was not pre-cued or when attention was directed to the target location intentionally (using a symbolic pre-cue displayed centrally). The hypothesis of two different mechanisms of attentional control in substitution masking was confirmed.

Endogenous cueing attenuates object substitution masking

“…However, in contrast to these studies, the results of a recent study by Luiga and Bachmann (2007) seem to question the general nature of the eVect of attention on OSM. SpeciWcally, their study was aimed at investigating whether endogenous and exogenous precueing of attention to the target location prior to target-plus-mask onset has a diVerent inXuence on OSM.…”

“…Two experiments are reported, both examining the time course of possible attenuating eVects on OSM by precueing attention to the upcoming target location, using a wide range of cue-target SOAs and a trailing mask duration of 0 and 160 ms. To preview the outcome of the two experiments, signiWcant attenuation of OSM with both exogenous and endogenous precueing was found, albeit at diVerent SOAs as could be expected based on the characteristic time courses of attentional eVects produced by the two types of precues (i.e., faster attentional orienting with exogenous precues; Cheal and Lyon, 1991;Müller and Rabbitt, 1989). In "General discussion", we oVer possible explanations for why Luiga and Bachmann, (2007) did not observe attenuation of OSM with endogenous cues.…”

“…Furthermore, given that both types of precues shorten the attentional time of contact but diVer in terms of sensory increases at the target location, Luiga and Bachmann suggested that the localized stimulation (e.g., the local exogenous precue), regardless of its attentional eVects, may facilitate sensory processing of successive stimuli (e.g., the target) thus attenuating OSM with localized exogenous but not central endogenous precues. As suggested by Luiga and Bachmann, this account of the eVect of diVerent types of precues on OSM tends to be more closely related to a feed-forward model of substitution masking, thus questioning the re-entrant model proposed by Enns and Di Lollo. Given the importance of the theoretical implications of the results reported by Luiga and Bachmann (2007), the aim of the present study was to further examine the dissociation between the eVects of exogenous (Experiment 1) and endogenous precueing (Experiment 2) on OSM. Two experiments are reported, both examining the time course of possible attenuating eVects on OSM by precueing attention to the upcoming target location, using a wide range of cue-target SOAs and a trailing mask duration of 0 and 160 ms. To preview the outcome of the two experiments, signiWcant attenuation of OSM with both exogenous and endogenous precueing was found, albeit at diVerent SOAs as could be expected based on the characteristic time courses of attentional eVects produced by the two types of precues (i.e., faster attentional orienting with exogenous precues; Cheal and Lyon, 1991;Müller and Rabbitt, 1989).…”

Objects with reduced visibility still contribute to size averaging

“…Consequently, the participants should have distributed their region of selection more broadly in the average size judgment than in the visibility test (Chong & Treisman, 2005b). Since OSM is strongly under conditions of broader selection (Enns, 2004;Luiga & Bachmann, 2007), it is likely that the masked circles were even less visible during the average size judgment task than during the visibility test. Also, because the visibility test was a two-alternative forced choice, it is possible that the test tapped into subconscious representations.…”

“…The participants would allocate focused attention to random locations among the possible circle locations before the appearance of the circle array. Because preallocating attention to a specific location can reduce the masking effects of OSM (Enns, 2004;Luiga & Bachmann, 2007), the sampled object could influence judgments equally between the simultaneous and delayed conditions. However, this alternative is made less likely by the fact that randomly sampling one object can explain only a small subset of size estimation demonstrations (Ariely, 2008;Chong et al, 2008;.…”