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ONSET and OFFSET inhibitions: effect of increase and decrease of cue luminance on manual reaction time to a visual
L R Carreiro1, L G Gawryszewski, F V Magalhães
1Departamento de Neurobiologia, Universidade Federal Fluminense, Niterói, RJ, Brasil.
Summary
This study examined how visual cue contrast affects reaction time (RT) to peripheral targets. Findings reveal that both early facilitation and inhibition of return are influenced by cue contrast, impacting visual attention.
Area of Science:
- Visual perception
- Cognitive psychology
- Human psychophysics
Background:
- Simple reaction time (RT) to peripheral visual targets exhibits early facilitation and inhibition of return (IOR) effects.
- These phenomena are typically studied with cues of a single contrast relative to the background.
Purpose of the Study:
- To investigate the influence of stimulus contrast inversion on early visual facilitation and inhibition of return.
- To determine if these attentional effects are related to cue onset or offset, and whether they vary with cue brightness.
Main Methods:
- Ten subjects performed a reaction time task with non-informative visual cues (S1) and targets (S2).
- Stimulus contrast was inverted (bright on dark, dark on bright) across different sessions.
- Trials varied based on cue-target interval (100 ms or 800 ms) and cue presentation (onset-based or offset-based).
Main Results:
- Early facilitation was observed when the cue-target interval was short (100 ms), regardless of contrast.
- Inhibition of return occurred at longer intervals (800 ms), with some contrast-dependent modulation.
- The results suggest that contrast influences the dynamics of visual attention shifts.
Conclusions:
- Both early facilitation and inhibition of return are robust phenomena, but their magnitude can be modulated by stimulus contrast.
- The findings contribute to understanding the interplay between low-level visual properties and higher-level attentional control.