the role of figural context & attention in masking

the role offigural context & attentionin masking

identification task A. Williams and Weisstein 1978

identification task A. Williams and Weisstein 1978 « Consequently, as well as relying on bottom-up activation, the perceptual process may also incorporate a top-down feedback activity or a same-level horizontal modulation between the representations of context and local features. » Breitmeyer and ögmen 2006

depth connectedness target-mask integration A. Williams and Weisstein 1981

depth connectedness target-mask integration other gestalt factors also modulating masking - collinearity (decreased masking) - symmetry (increased masking) - similarity (increased masking) A. Williams and Weisstein 1981

target-only integration Ramachandran and Cobb 1995, experiment 1

target-only integration Constant SOA = 116 ms Subjective rating of visibility: Attending squares: 1.17 Attending circles: 4.08 Ramachandran and Cobb 1995, experiment 2

conclusion (?) figural context modulates the masking function ... ... but ! some researchers may have combined selective attention and grouping others have confounded space- or location-based attention with object- or configuration-based attention

conclusion (?) figural context modulates the masking function ... ... but ! some researchers may have combined selective attention and grouping others have confounded space- or location-based attention with object- or configuration-based attention ... ... therefore unclear if modulation of masking is due to grouping or space/object-based attention

space-based attentional effects Enns and DiLollo 1997, experiment 1

space-based attentional effects • masking with four-dot mask not only • due to low-level contour interactions Enns and DiLollo 1997, experiment 1

space-based attentional effects • masking insensitive to contour • proximity at parafoveal locations Enns and DiLollo 1997, experiment 2

space-based attentional effects • four-dot masking increased with number of targets Enns and DiLollo 1997, experiment 3

conclusions • four-dot masking cannot be explained by contour-based mechanisms commonly used to explain meta-contrast. • one explanation might be incomplete focusing of spatial attention space-based attentional effects Enns and DiLollo 1997

conclusions • four-dot masking cannot be explained by contour-based mechanisms commonly used to explain meta-contrast. • one explanation might be incomplete focusing of spatial attention space-based attentional effects « ... these data suggest that the need for observers to distribute their attention over all three targets, prior to the onset of the four dots, resulted in masking of even the foveated target shape. » Enns and DiLollo 1997

space-based attentional effects masking increased with number of targets Tata 2002, experiment 1

space-based attentional effects correct attentional cue decreased masking Tata 2002, experiment 2

space-based attentional effects pop-out effect reduced masking Tata 2002, experiment 3

space-based attentional effects • conclusions • results suggest that theories based on low-level processes early in visual system is insufficient to explain metacontrast masking. • visual selective attention plays an important role in metacontrast masking Tata 2002

inattentional blindness, is an observed phenomenon of the inability to perceive features in a visual scene when the observer is not attending to them. object/feature-based attentional effects

inattentional blindness, is an observed phenomenon of the inability to perceive features in a visual scene when the observer is not attending to them. object/feature-based attentional effects more familiar, typical, or salient visual objects have higher probability of resisting IB, which leads to less masking compared to items less resistant to IB.

mechanisms of masking: • integration through common synthesis • interchannel inhibition • replacement principle central attentional effects Michaels and Turvey 1979

mechanisms of masking: • camouflage masking • interruption central attentional effects another role of attention: increase spatiotemporal resolution of objects presented to nonfoveal regions • masking by four dots possible because: • unattended targets are coded with low spatiotemporal resolution • attended four-dot mask have an advantage when competing for higher level mechanisms involved in object recognition Enns and DiLollo 1997

mechanisms of masking: • camouflage masking • interruption central attentional effects another role of attention: increase spatiotemporal resolution of objects presented to nonfoveal regions • masking by four dots possible because: • unattended targets are coded with low spatiotemporal resolution • attended four-dot mask have an advantage when competing for higher level mechanisms involved in object recognition Object substitution masking Enns and DiLollo 1997

conclusions • figural context and masking • gestalt factors influence masking • target integrated in an object (2D/3D) is less masked • different temporal properties governs operation of different gestalt factors of figural organization • target being part of larger gestalt is masked less than when being part of a meaningless arrangement Breitmeyer and ögmen 2006

conclusions • figural context and masking • gestalt factors influence masking • target integrated in an object (2D/3D) is less masked • different temporal properties governs operation of different gestalt factors of figural organization • target being part of larger gestalt is masked less than when being part of a meaningless arrangement • attention and masking • attending features or location of targets enhances visibility of the target • centrally controlled attention processes mediate transfer of information from iconic levels to post-iconic levels predicts level of performance Breitmeyer and ögmen 2006

conclusions both figural context and attention affects visibility of a target, but this is a general feature of attention/figural context when studied in a variety of other experimental paradigms Breitmeyer and ögmen 2006

conclusions both figural context and attention affects visibility of a target, but this is a general feature of attention/figural context when studied in a variety of other experimental paradigms « Thus both top-down influences on backward masking can be viewed simply as modulators of masking analogous to the bottom-up modulatory effects produced by varying certain physical parameters of the target and mask stimuli » Breitmeyer and ögmen 2006

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the role of figural context & attention in masking