Attention to multiple locations is limited by spatial working memory capacity

Abstract

What limits the ability to attend several locations simultaneously? There are two possibilities: Either attention cannot be divided without incurring a cost, or spatial memory is limited and observers forget which locations to monitor. We compared motion discrimination when attention was directed to one or multiple locations by briefly presented central cues. The cues were matched for the amount of spatial information they provided. Several random dot kinematograms (RDKs) followed the spatial cues; one of them contained task-relevant, coherent motion. When four RDKs were presented, discrimination accuracy was identical when one and two locations were indicated by equally informative cues. However, when six RDKs were presented, discrimination accuracy was higher following one rather than multiple location cues. We examined whether memory of the cued locations was diminished under these conditions. Recall of the cued locations was tested when participants attended the cued locations and when they did not attend the cued locations. Recall was inaccurate only when the cued locations were attended. Finally, visually marking the cued locations, following one and multiple location cues, equalized discrimination performance, suggesting that participants could attend multiple locations when they did not have to remember which ones to attend. We conclude that endogenously dividing attention between multiple locations is limited by inaccurate recall of the attended locations and that attention poses separate demands on the same central processes used to remember spatial information, even when the locations attended and those held in memory are the same.

The Effect of Attentional Cueing and Spatial Uncertainty in Visual Field Testing

“…In the case of size III stimuli, the location of the presentation also affected the magnitude of improvement in performance. Taken together, these results are consistent with previous studies using similar [ 22 ] or slightly different paradigms [ 14 , 15 , 19 , 39 ], which have shown that cueing certain stimulus properties facilitates improvement in detection ability. The effect of cueing was found to diminish with increasing number of elements cued, eventually returning to baseline performance following an exponential decay [ 40 ], consistent with previous studies on working memory showing that observers can accurately recall the visual details of three or four elements [ 41 , 42 ], and allocation of attention to multiple spatial locations [ 39 ] and set sizes [ 43 ].…”

“…Taken together, these results are consistent with previous studies using similar [ 22 ] or slightly different paradigms [ 14 , 15 , 19 , 39 ], which have shown that cueing certain stimulus properties facilitates improvement in detection ability. The effect of cueing was found to diminish with increasing number of elements cued, eventually returning to baseline performance following an exponential decay [ 40 ], consistent with previous studies on working memory showing that observers can accurately recall the visual details of three or four elements [ 41 , 42 ], and allocation of attention to multiple spatial locations [ 39 ] and set sizes [ 43 ]. The lack of effect with size V stimuli is consistent with previous suggestions that larger stimuli are less subject to the effects of attention and variability [ 27 , 44 ], as stimulus size has been described to be a guiding attribute for visual attention [ 45 ], visual search tasks [ 46 ] and task difficulty [ 19 , 43 ].…”

Eccentricity effects in vision and attention

“…Thus, knowing where to direct attention did not aid performance. It is conceivable, however, that participants were unable to make use of the information given regarding the eccentricity of the targets in a specific trial; it might not be possible to cue multiple target locations using only an endogenous cue, either because it is not possible to select multiple target locations in parallel or because working memory cannot retain the spatial information accurately (see for example Close et al, 2014). Although we cannot exclude that an exogenous cue would have affected performance, the employment of an endogenous cue did not.…”

Reducing Spatial Uncertainty Through Attentional Cueing Improves Contrast Sensitivity in Regions of the Visual Field With Glaucomatous Defects

“… 19 , 40 Other potential confounders such as mental load and divided attention are overcome by conducting the test in a controlled environment. 41 Previous studies have highlighted the importance of maintaining attention throughout perimetric testing with a resultant improvement in reliability 42 and performance 17 , 18 , 43 – 45 by reducing spatial uncertainty. Conversely, divided attention worsens performance.…”

“…The exponential decay in performance and the number of points to the plateau of cueing effect in the present study is consistent with previous work in working memory, attentional load, and attentional allocation. 45 – 49 …”