In the present study, I examined how the temporal and spatial relationship between two visual targets (Tl and T2) affects the recall of both targets when they are embedded in rapidly displayed distractors. Presented on a trial were two synchronized streams of characters, one to the left and the other to the right ofthe fixation, Independent oftheir spatial relationship, a If-shaped curve described the recall of the second target (T2) as a function of stimulus onset asynchrony (SOA) between T1 and T2. It indicated the presence of the attentional blink with a T2 deficit sparing up to about 150-to 200-msec SOA. However, T2 deficit was greater at short SOAs (up to about 250 msec) when Tl and T2 occurred at different locations than when they occurred at a common location. When SOAwas short (100msec or so), recall of Tl was impaired when Tl and T2 occurred at a common location, but not when they were at different locations. The present findings can be reconciled with existing models (e.g., the interference model and the two-stage model) by distinguishing automatic and controlled attention gating processes at the transfer of perceptual representations to a more durable storage (e.g., visual short-term memory).

A new paradigm combines attentional cuing and rapid serial visual presentation to disentangle the effects of perceptual filtering and location selection. Observers search successive, superimposed arrays, in which feature values are alternated for a target numeral among letters. Two dimensions, size (small, large) and color (red, green) are tested. Selective attention to feature values is jointly manipulated by instructions, presentation probabilities, and payoffs. In Experiment 1, the attended feature provides temporal, not spatial, information; observers show no attentional costs or benefits in response accuracy. In Experiment 2, the attended feature indicates a unique location; observers show consistent attentional costs and benefits. Selective attention to a particular size or color does not cause perceptual exclusion or admission of items containing that feature; it acts by guiding search processes to spatial locations that contain the to-be-attended feature.

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In a novel choice attention-gating paradigm, observers monitor a stream of 3 ϫ 3 letter arrays until a tonal cue directs them to report 1 row. Analyses of the particular arrays from which reported letters are chosen and of the joint probabilities of reporting pairs of letters are used to derive a theory of attention dynamics. An attention window opens 0.15 s following a cue to attend to a location, remains open (minimally) 0.2 s, and admits information simultaneously from all the newly attended locations. The window dynamics are independent of the distance moved. The theory accounts for about 90% of the variance from the over 400 data points obtained from each of the observers in the 3 experiments reported here. With minor elaborations, it applies to all the principal paradigms used to study the dynamics of visual spatial attention.We explored a method of measuring the trajectory of spatial attention that is analogous to measuring the trajectory of subatomic particles in a Glaser bubble chamber (Gray & Isaacs, 1975). In the bubble chamber, a three-dimensional space is filled with a superheated liquid. A particle traveling through the liquid causes rapid localized boiling-microscopic bubbles-along its path. The bubbles can be photographed to indicate the particle's track and the tracks of decay and reaction products that it might produce. The complete tracks of all the bubbles define the trajectory of the particle (see Figure 1). In our procedure, a two-dimensional 3 ϫ 3 array is filled with letters. These letters change 7 to 10 times per second. Thus each letter occupies a little cube in a threedimensional space-time volume. During a movement of voluntary attention, some of the letters along the attention trajectory are entered into memory. The track of the remembered letters defines the trajectory of attention through the three-dimensional volume.Once attention trajectories have been measured in a threedimensional array of letters, it would be desirable to know whether these trajectories are the same trajectories as have been inferred from other procedures, such as partial report, which involves transfer from iconic memory (Neisser, 1967) to durable storage (Coltheart, 1980) of letters in a single two-dimensional array. A strong test of the possibility of equivalent attention trajectories in different experimental paradigms requires that all paradigms be tested with the same observers and with similar stimulus materials. Therefore, in addition to the main experiment, which measured attention shifts in three-dimensional letter arrays, two supplementary experiments were conducted with two-dimensional letter arrays: partial-report and whole-report procedures, each with and without poststimulus masks, all with the same 3 ϫ 3 letter arrays.Whereas estimating an attention trajectory from the letter-filled three-dimensional displays is relatively straightforward, estimating attention trajectories from partial-report experiments is complicated, requiring a full model of information decay, information transfer rates fro...

This study investigated whether “intentional” instructions could improve older adults' object memory and object-location memory about a scene by promoting object-oriented viewing. Eye movements of younger and older adults were recorded while they viewed a photograph depicting 12 household objects in a cubicle with or without the knowledge that memory about these objects and their locations would be tested (intentional vs. incidental encoding). After viewing, participants completed recognition and relocation tasks. Both instructions and age affected viewing behaviors and memory. Relative to incidental instructions, intentional instructions resulted in more accurate memory about object identity and object-location binding, but did not affect memory accuracy about overall positional configuration. More importantly, older adults exhibited more object-oriented viewing in the intentional than incidental condition, supporting the environmental support hypothesis.