title: Metacontrast masking and attention do not interact.
abstract: Visual masking and attention have been known to control the transfer of information from sensory memory to visual short-term memory. A natural question is whether these processes operate independently or interact. Recent evidence suggests that studies that reported interactions between masking and attention suffered from ceiling and/or floor effects. The objective of the present study was to investigate whether metacontrast masking and attention interact by using an experimental design in which saturation effects are avoided. We asked observers to report the orientation of a target bar randomly selected from a display containing either two or six bars. The mask was a ring that surrounded the target bar. Attentional load was controlled by set-size and masking strength by the stimulus onset asynchrony between the target bar and the mask ring. We investigated interactions between masking and attention by analyzing two different aspects of performance: (i) the mean absolute response errors and (ii) the distribution of signed response errors. Our results show that attention affects observers' performance without interacting with masking. Statistical modeling of response errors suggests that attention and metacontrast masking exert their effects by independently modulating the probability of "guessing" behavior. Implications of our findings for models of attention are discussed.
authors.affiliation: Department of Electrical and Computer Engineering, University of Houston, N308 Engineering Building 1, Houston, TX, 77204-4005, USA.|Center for Neuro-Engineering and Cognitive Science, University of Houston, Houston, TX, 77204-4005, USA.
authors.forename: Sevda
authors.initials: S
authors.lastname: Agaoglu
authors.affiliation: Department of Psychology, University of Houston, Houston, TX, 77204-5022, USA.|Center for Neuro-Engineering and Cognitive Science, University of Houston, Houston, TX, 77204-4005, USA.
authors.forename: Bruno
authors.initials: B
authors.lastname: Breitmeyer
authors.affiliation: Department of Electrical and Computer Engineering, University of Houston, N308 Engineering Building 1, Houston, TX, 77204-4005, USA. ogmen@uh.edu.|Center for Neuro-Engineering and Cognitive Science, University of Houston, Houston, TX, 77204-4005, USA. ogmen@uh.edu.
authors.forename: Haluk
authors.initials: H
authors.lastname: Ogmen
mesh_terms: D001288:Attention / Q000502:physiology*; D006801:Humans; D008570:Memory, Short-Term / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology*
keywords: Attention; Metacontrast masking; Visual masking