Objectbased OB approach: YES

1
Is Object-Based Attention Mandatory? Strategic
Control over Object-Based Attention Menahem Yeari
and Morris Goldsmith University of Haifa, Israel
Previous research No clear answer! 3 approaches
3 answers
When attending to part of an object, must one
necessarily attend to the entire object?
Experiment 1 Perceptual group
Experiment 2 UC object
Paradigm
OR

• Stimuli and Procedure
• Following a fixation cross, participants were
  induced to attend to a central arrow cue, that
  varied in its validity.
• The cue was presented together with two (Exp. 1)
  or four (Exp. 2) peripheral shapes that marked
  the potential target locations.
• One of the peripheral shapes was either
  perceptually grouped (Exp. 1) or uniformly
  connected (Exp. 2) with the arrow cue, to form a
  single perceptual cue-object.
• The cue always pointed to a diametrically
  opposite, "different-object" location, than its
  own same-object location.
• Participants' task was to discriminate the target
  letter T or L.
• In addition, to insure attention to the cue
  (especially when cue-validity was low),
  participants were to refrain from responding when
  they detected a small gap in the arrow (20 of
  trials).

Is object-based attention is mandatory?
Object-based (OB) approach YES! The basic units
of attentional selection are discrete objects.
Directing attention to a part or region of an
object necessarily yields a processing advantage
for all parts and features of the object
1. Evidence OB effects observed even though OB
attention is neither strategically expedient nor
explicitly required by the task 2. Caveat This
might just reflect a general tendency or default
mode, that is used unless there is some special
reason to do otherwise.
Space-Based (SB) approach NO! Attention can
select unparsed regions of space in a manner
analogous to a spotlight illuminating those
regions 3, irrespective of object segmentation
and grouping. Evidence OB effects on attention
are not observed under all conditions 4.
Caveat This implies that OB selection is not
universal. OB attention might still be
mandatory, however, whenever the boundary
conditions for such selection are met.

• Main manipulations (see summary table below)
• Between-subjects
• Cue validity - to manipulate the strategic
  incentive to avoid OB attention (preferential
  attention to the entire cue-object)
• Invalid cue cued different-object targets and
  uncued same-object targets are equally likely
  no/weak anti-OB incentive
• Valid cue cued different-object targets are much
  more likely (80) than uncued same-object targets
  strong anti-OB incentive
• Within-subjects
• Cue-target SOA Several SOAs were mixed within
  blocks.
• Cue-object presence (valid cue only) a no
  cue-object control condition was added for
  comparison, to reveal any residual cost of
  avoiding OB attention.

Strategic approach POSSIBLY OB attention is the
default mode of selection, but the choice of
selection mode is in fact under strategic
control. Evidence Two studies directly
manipulated the expediency of object-based
attention, by manipulating the probabilities of
same-object/group or different-object/group
targets. When made strategically inexpedient,
grouping effects were attenuated but not
eliminated in a serial scanning task 6, and
object-based effects were eliminated at long but
not at short cue-target SOAs in a spatial cueing
task 7. Caveat These results raise the
possibility that OB effects are eliminated only
if there is sufficient time to recover from an
initial mandatory OB allocation.
Results Exp. 2 A Invalid Cue Cue Object
OB effect (all SOAs) B Valid Cue Cue Object
SB effect (SOA300) No significant difference
between (uncued) same-object RT and uncued
different-object RT at any SOA (all F's lt 1) C
Valid cue No Cue-Object SB effect (SOA300) No
significant difference or interaction with the
cue-object present condition at any SOA (all F's
lt 1)
Summary of design and results

• Results Exp. 1
• A Invalid Cue Cue-Object OB effect
• a significant RT advantage for same-object
  targets at SOA gt 100
• B Valid Cue Cue-Object SB effect at SOA
  300
• No significant OB effect at any SOA
• Significant RT advantage for cued
  different-object targets (SB validity effect) at
  SOA 300
• C Valid Cue No Cue-Object SB effect at SOA
  300
• No significant difference or interaction with the
  cue-object present condition at any SOA (all F's
  lt 1)

Between-subjects
Within-subjects
Current research clarifying the caveats

• General discussion
• Object based effects can be completely eliminated
  even when the object is uniformly connected.
• All of the research hypotheses were supported.
• Mode of attentional selection is under strategic
  control
• Object based attention is the default selection
  mode From an evolutionary perspective, objects
  have a general informational advantage over
  unorganized (meaningless) features appearing in
  arbitrary spatial regions 8.
• Space based attention mode can be adopted when
  the strategic advantage of allocating attention
  irrespective of object boundaries and grouping is
  strong enough, in the task at hand.
• Issue conclusions pertain to endogenous (?)
  selection of a centrally presented part of an
  object.
• A parsimonious reconciliation of object-based and
  space-based attention Attention tends to be
  allocated to the most relevant-informative unit
  of space, taking into account both enduring and
  transitory strategic considerations.

• Research goal
• To examine whether OB selection can be completely
  eliminated (at short SOAs as well) when such
  selection is made very inexpedient, under
  conditions which it is otherwise observed.
• General paradigm
• Participants attended to an part of an object
  (central cue).
• Targets could appear either at the other part of
  the object (same-object) or at an equally distant
  location in a different object.
• The strategic incentive to avoid preferential
  attention to the entire object (OB) was
  manipulated by varying the probability of
  different-object vs. same-object targets
• Weak/no anti-OB incentive Target is equally
  likely to appear at any possible location
  (same-object or different-object).
• Strong anti-OB incentive Different-object target
  is much more likely than same-object target.
• Hypothesis Predictions
• OB is the default mode of attention OB effect
  will be observed under the weak/no anti-OB
  incentive.
• OB attention is not mandatory OB effect will be
  eliminated at any SOA under the strong anti-OB
  incentive.

• Preliminary conclusions
• OB attention is not mandatory, but rather is a
  default tendency (Condition A) which can be
  completely overridden (Condition B SOA
  manipulation), without any residual cost
  (Condition B vs. C), when it is strategically
  expedient to do so.
• Issue Perhaps OB effects can be eliminated only
  when the object is composed of distinct parts, in
  which case each part might still be attended to
  in an OB manner.

• References
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• Posner, M. I. (1980). Orienting of attention.
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• Goldsmith, M., Yeari M. (2003). Modulation of
  object-based attention by spatial focus under
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• Shomstein, S., Yantis, S. (2004). Configural
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• Beck, D. M., Palmer, S. E. (2002). Top-down
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• Yantis, S. (1996). Attentional capture in vision.
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