Visual
Orienting Occurs Asymmetrically in Horizontal vs. Vertical Planes
M. Nomura, M. Kataliata, & K. Hashiya |
Recent
behavioral data have shown that central gaze direction triggers reflexive
shifts of attention to the cued location. Considering findings on
the ecological adaptation of human vision, the authors expected that
such a cueing effect would occur asymmetrically in horizontal and
vertical planes. Participants detected a target letter appearing
on a PC monitor after the brief presentation of a nonpredictive head-cue
(Experiment 1), profile head-cue (Experiment 2), or arrow-cue (Experiment
3) directed up, down, left, or right of fixation. In all experiments,
a cueing effect was observed only when the cue was directed horizontally,
but no significant effect was observed in the vertical plane. The
results also showed that RTs to a target appearing horizontally were
shorter than RTs to a target appearing vertically, irrespective of
the cue direction. These results might reflect humans' adaptation
for extension of the visual field in the horizontal plane as a terrestrial
primate species. Key words: visual orienting, asymmetry, horizontal, vertical |