Spatial attention is necessary for object-based attention: Evidence from temporal-order judgments.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Visual Perception

Background:

• Attentional selection is crucial for processing information and relies on various representational formats.
• Previous research predominantly used spatial cueing paradigms to investigate object-based attention, leaving its emergence independent of spatial markers unclear.

Purpose of the Study:

• To investigate whether object-based attentional guidance can emerge in the absence of any spatial cueing.
• To introduce a novel method for measuring object-based attentional effects.

Main Methods:

• Utilized a temporal-order judgment (TOJ) task with two rectangles as objects.
• Participants judged the temporal order of two target stimuli presented on the same or different objects.
• Measured perceived simultaneity (PSS) to assess processing efficiency.

Main Results:

• A 'hill' target was processed faster, indicated by a positive PSS.
• When targets appeared equally on same and different objects, PSS was not modulated by object structure.
• Object representations modulated attentional allocation only when spatially cued (endogenously).

Conclusions:

• Object representations do not inherently guide attentional selection without spatial cues or biases.
• Spatial cueing is necessary for object-based attentional effects to manifest.
• The findings provide new constraints for theories of object-based attention and introduce a novel measurement paradigm.