Why don't we see changes? The role of attentional bottlenecks and limited visual memory

Abstract

Seven experiments explore the role of bottlenecks in selective attention and access to visual shortterm memory in the failure of observers to identify clearly visible changes in otherwise stable visual displays. Experiment One shows that observers fail to register a color change in an object even if they are cued to the location of the object by a transient at that location as the change is occurring. Experiment Two shows the same for orientation change. In Experiments Three and Four, attention is directed to specific objects prior to making changes in those objects. Observers have only a very limited memory for the status of recently attended items. Experiment Five reveals that observers have no ability to detect changes that happen after attention has been directed to an object and before attention returns to that object. In Experiment Six, attention is cued at rates that more closely resemble natural rates and Experiment Seven uses natural images. Memory capacity remains very small (<4 items).If you ask typical observers, outside of a vision research laboratory, what they are seeing right now, they will probably tell you that they are seeing a large number of objects placed in a spatially continuous scene. If you ask them if they are seeing all of that at the same time, they will look at you quizzically but they will agree that all of the objects seem to be visually present in the present instant of time. It hardly seems like much of a question. However, if you ask atypical observers, those who have been studying the question over the past 20 years or so, the answers may be quite different. A range of phenomena suggest that human observers are unable to perform tasks that would seem to be quite trivial if we could see what was in front of our eyes in the uncomplicated manner suggested by naïve introspection.Change blindness is one of the most striking of these phenomena. In a typical change blindness paradigm, the observer is told to monitor an image for a change. As long as transients are masked and as long as the observer is not attending to the object that is changing, observers will be very poor at detecting quite substantial changes. These can range from changes to significant objects in natural scenes to changes in "basic features" like color (Phillips, 1974;Rensink, O'Regan, & Clark, 1997;Simons, 2000;Simons & Levin, 1997).Similar failures to report what is in front of the eyes occur when observers are attending to one aspect of a display and subsequently queried about another. Thus, Mack and Rock (1998) found that observers who were answering a question about a pair of lines would fail to report salient stimuli presented at fixation ("inattentional blindness"). Simons Neisser & Becklen, 1975) have shown that observers who were monitoring one set of actors would fail to notice other actors (e.g. a woman in a gorilla suit) as they entered and left a scene (Simons & Chabris, 1999).Some have argued that these results demonstrate that we only "see" the current object of attention and that the re...

Change detection on a hunch: Pre-attentive vision allows “sensing” of unique feature changes

“…Previous studies have demonstrated that in visual search and change detection experiments, identification is dependent on localization (Treisman & Gelade, 1980;Treisman & Gormican, 1988;Dukewich & Klein, 2009;Ghorashi et al, 2010;Busch et al, 2010a;Schneider & Wascher, 2013;Chan & Hayward, 2009;Watanabe, 2003;Wolfe et al, 2006;Agostinelli et al, 1986;Becker et al, 2000;Hughes et al, 2012). Thus, Experiment 2 investigated whether change detection without localization also implies a failure to identify the changing feature.…”

“…Numerous studies have investigated whether or not detection, localization, and recognition can be dissociated experimentally in visual search tasks or change detection tasks. Some of these studies found a dissociation of detection, localization, or recognition (Treisman & Gelade, 1980;Treisman & Gormican, 1988;Dukewich & Klein, 2009;Ghorashi et al, 2010;Busch et al, 2010a;Busch et al, 2010b;Schneider & Wascher, 2013;Chan & Hayward, 2009;Watanabe, 2003;Wolfe et al, 2006;Agostinelli et al, 1986;Becker et al, 2000;Turatto & Bridgeman, 2005;Hughes et al, 2012) while others found them to be similar (Luck & Vogel, 1997;Green, 1992;Joseph et al, 1997;Busey & Palmer, 2008;Zehetleitner & Müller, 2010) or found recognition to be conditional upon localization Donk and Meinecke (2001). Thus, whether target detection in visual search for static patterns can occur in the absence of localization or object recognition is still debated.…”

Dimension-based attention in visual short-term memory

“…Pilling and Gellatly (2013) observed similar effects using a different type of VSTM task: an abrupt-probe task (Pilling & Gellatly, 2011;Wolfe et al, 2006). In the task, participants viewed a display containing from nine to 36 colored shapes.…”

“…One possibility is that attention affects encoding processes. Attention is generally considered the Bgatekeeperf or VSTM; indeed, spatial attention seems to be a prerequisite for items to become encoded into VSTM (Averbach & Coriell, 1961;Awh, Vogel, & Ohr, 2006;Sperling, 1960;Wolfe, Reinecke, & Brawn, 2006). However, other evidence has shown that directions of spatial attention can influence VSTM even after encoding has taken place; cues presented during the retention interval also have a reliable effect on performance.…”

Investigating the parameters of transsaccadic memory: inhibition of return impedes information acquisition near a saccade target

“…One of the challenges of integrating visual information is the inability of the visual system to process all information simultaneously (Wolfe, 1994). Selection of visual information is therefore crucial as we are only able to attend to a small amount of information at any given time and unattended information is lost (Wolfe, Reinecke, & Brawn, 2006). Loss of information can occur during different stages of visual processing and is especially true whilst executing a saccade.…”