For details, please see:
MacKeben, M. (1999) Sustained Focal Attention and Peripheral Letter Recognition. Spatial Vision 12/1, 51-71.
 Figure A.
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Figure A shows the sequence of events as 3-dimensional and timeline diagrams. Attention had to beheld at the cued location during waiting time of variable duration (2.5 to 4 s; hatched area in the time line diagram). Target height was constant (36 arcmin), target duration varied between subjects (66-167 ms). |
Figure B, below, shows the performance fields for all subjects in 2 age groups. Length of radial spikes = % correct for the location at which the spike is pointing, end points are connected to form field (Outermost ring = 100% correct). Central disks ("10%") denote chance level (10 Sloan letters), the radius of the surrounding black ring shows the spatial average of performance in 96 trials without cue. Regular octagons show "ideal" performance, i.e. what the field would look like if performance were equally good in all locations and at the level of the best location. Circled "T"s indicate temporal side. Subject initials and ages are in upper left corners, eye used in the upper right.
Performance differences between location and between subjects were statistically significant (p< 0.01). Characteristic field distortions were also present after transformation into d'-values. Even in the worst locations, same size letters were recognized when the duration was 500ms or more. Neither spatial nor temporal variations could account for the field distortions. It was hypothesized that they could be a spatial characteristic of the sustained attentional mechanism.
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Figure B.
This research has been supported by the AARP Andrus Foundation and the Smith- Kettlewell Eye Research Institute.
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