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Spatial and temporal attention modulate the early stages of face processing: behavioural evidence from a reaching paradigm.

Quek GL, Finkbeiner M - PLoS ONE (2013)

Bottom Line: In the present study, we reconcile this divide by using a continuous behavioural response measure that indexes face processing at a temporal resolution not available in discrete behavioural measures (e.g. button press).Using reaching trajectories as our response measure, we observed that although participants were able to process faces both when attended and unattended (as others have found), face processing was not impervious to attentional modulation.Attending to the face conferred clear benefits on sex-classification processes at less than 350ms of stimulus processing time.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Science, ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, New South Wales, Australia. genevieve.quek@mq.edu.au

ABSTRACT
A presently unresolved question within the face perception literature is whether attending to the location of a face modulates face processing (i.e. spatial attention). Opinions on this matter diverge along methodological lines - where neuroimaging studies have observed that the allocation of spatial attention serves to enhance the neural response to a face, findings from behavioural paradigms suggest face processing is carried out independently of spatial attention. In the present study, we reconcile this divide by using a continuous behavioural response measure that indexes face processing at a temporal resolution not available in discrete behavioural measures (e.g. button press). Using reaching trajectories as our response measure, we observed that although participants were able to process faces both when attended and unattended (as others have found), face processing was not impervious to attentional modulation. Attending to the face conferred clear benefits on sex-classification processes at less than 350ms of stimulus processing time. These findings constitute the first reliable demonstration of the modulatory effects of both spatial and temporal attention on face processing within a behavioural paradigm.

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Trial structure for Expts 1A & 1B.Here we depict a congruent trial, in which the prime and target were of the same sex (i.e. female). Each frame consisted of two vertically displaced panels and a central fixation point, presented for identical durations within each frame. Prime and target items always appeared in the upper and lower panels respectively. Both experiments used a variable fixation duration (750 ms–1500 ms); in Expt 1A, the sudden onset and offset of a yellow bar captured participants’ transient spatial attention at the prime (upper) or target (lower) location. The individuals shown here provided written informed consent to the reproduction of their photographs in publication.
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pone-0057365-g001: Trial structure for Expts 1A & 1B.Here we depict a congruent trial, in which the prime and target were of the same sex (i.e. female). Each frame consisted of two vertically displaced panels and a central fixation point, presented for identical durations within each frame. Prime and target items always appeared in the upper and lower panels respectively. Both experiments used a variable fixation duration (750 ms–1500 ms); in Expt 1A, the sudden onset and offset of a yellow bar captured participants’ transient spatial attention at the prime (upper) or target (lower) location. The individuals shown here provided written informed consent to the reproduction of their photographs in publication.

Mentions: In the present study, we sought to document the behavioural complement of these early neurophysiological effects of spatial attention. Our response paradigm was specifically designed to examine face processing during the first 350 ms of stimulus processing. Rather than pressing a button to indicate their response, in our task subjects classified the sex of a target face by reaching out to touch the left or right side of the computer monitor. Importantly, we used a motion-capture device (Optotrak) to sample the position of the hand during the reaching response, which resulted in a high resolution continuous dataset on each trial. There is now a burgeoning literature on the use of such continuous movement measures in cognitive psychology [32]–[36], which are purportedly able to capture dynamic interactions between multiple cognitive processes reflected in motor output [37]. The principal advantage of reaching responses in the present study is that they enable subjects to begin their classification response very early without penalty. We required participants to initiate their reaching movement within 350 ms of the target’s onset, ensuring that the initial stages of their classification movements were (frequently) made while subjects were still accumulating evidence about the target. In light of the effects documented in the ERP literature, we reasoned that the attentional effects on face processing would be most visible during this early stage of stimulus processing. We combined this continuous behavioural measure with an adaptation of the masked priming paradigm [38], in which the target face always appeared in the lower of two vertically displaced panels (see Figure 1), and was temporally preceded by a prime face that always appeared in the upper panel. The prime stimuli were either the same sex as the target (i.e. congruent), or of the opposite sex (incongruent), were presented very briefly (50 ms) and immediately backward masked, such that participants were generally unable to report seeing the prime. We assessed the extent to which the masked face was processed by examining how prime-target congruence modulated subjects’ overt response to the target. In button-press versions of this paradigm, participants typically respond faster and more accurately to congruent prime-target pairings than to incongruent pairs, a result termed the Masked Congruence Effect (MCE) [16], [39]–[41]. The MCE thus provides an index of prime processing – the key question here is whether the allocation of attention to the prime’s location (in space or time) modulates prime processing at all (i.e. larger congruence effects for attended primes).


Spatial and temporal attention modulate the early stages of face processing: behavioural evidence from a reaching paradigm.

Quek GL, Finkbeiner M - PLoS ONE (2013)

Trial structure for Expts 1A & 1B.Here we depict a congruent trial, in which the prime and target were of the same sex (i.e. female). Each frame consisted of two vertically displaced panels and a central fixation point, presented for identical durations within each frame. Prime and target items always appeared in the upper and lower panels respectively. Both experiments used a variable fixation duration (750 ms–1500 ms); in Expt 1A, the sudden onset and offset of a yellow bar captured participants’ transient spatial attention at the prime (upper) or target (lower) location. The individuals shown here provided written informed consent to the reproduction of their photographs in publication.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585364&req=5

pone-0057365-g001: Trial structure for Expts 1A & 1B.Here we depict a congruent trial, in which the prime and target were of the same sex (i.e. female). Each frame consisted of two vertically displaced panels and a central fixation point, presented for identical durations within each frame. Prime and target items always appeared in the upper and lower panels respectively. Both experiments used a variable fixation duration (750 ms–1500 ms); in Expt 1A, the sudden onset and offset of a yellow bar captured participants’ transient spatial attention at the prime (upper) or target (lower) location. The individuals shown here provided written informed consent to the reproduction of their photographs in publication.
Mentions: In the present study, we sought to document the behavioural complement of these early neurophysiological effects of spatial attention. Our response paradigm was specifically designed to examine face processing during the first 350 ms of stimulus processing. Rather than pressing a button to indicate their response, in our task subjects classified the sex of a target face by reaching out to touch the left or right side of the computer monitor. Importantly, we used a motion-capture device (Optotrak) to sample the position of the hand during the reaching response, which resulted in a high resolution continuous dataset on each trial. There is now a burgeoning literature on the use of such continuous movement measures in cognitive psychology [32]–[36], which are purportedly able to capture dynamic interactions between multiple cognitive processes reflected in motor output [37]. The principal advantage of reaching responses in the present study is that they enable subjects to begin their classification response very early without penalty. We required participants to initiate their reaching movement within 350 ms of the target’s onset, ensuring that the initial stages of their classification movements were (frequently) made while subjects were still accumulating evidence about the target. In light of the effects documented in the ERP literature, we reasoned that the attentional effects on face processing would be most visible during this early stage of stimulus processing. We combined this continuous behavioural measure with an adaptation of the masked priming paradigm [38], in which the target face always appeared in the lower of two vertically displaced panels (see Figure 1), and was temporally preceded by a prime face that always appeared in the upper panel. The prime stimuli were either the same sex as the target (i.e. congruent), or of the opposite sex (incongruent), were presented very briefly (50 ms) and immediately backward masked, such that participants were generally unable to report seeing the prime. We assessed the extent to which the masked face was processed by examining how prime-target congruence modulated subjects’ overt response to the target. In button-press versions of this paradigm, participants typically respond faster and more accurately to congruent prime-target pairings than to incongruent pairs, a result termed the Masked Congruence Effect (MCE) [16], [39]–[41]. The MCE thus provides an index of prime processing – the key question here is whether the allocation of attention to the prime’s location (in space or time) modulates prime processing at all (i.e. larger congruence effects for attended primes).

Bottom Line: In the present study, we reconcile this divide by using a continuous behavioural response measure that indexes face processing at a temporal resolution not available in discrete behavioural measures (e.g. button press).Using reaching trajectories as our response measure, we observed that although participants were able to process faces both when attended and unattended (as others have found), face processing was not impervious to attentional modulation.Attending to the face conferred clear benefits on sex-classification processes at less than 350ms of stimulus processing time.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Science, ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, New South Wales, Australia. genevieve.quek@mq.edu.au

ABSTRACT
A presently unresolved question within the face perception literature is whether attending to the location of a face modulates face processing (i.e. spatial attention). Opinions on this matter diverge along methodological lines - where neuroimaging studies have observed that the allocation of spatial attention serves to enhance the neural response to a face, findings from behavioural paradigms suggest face processing is carried out independently of spatial attention. In the present study, we reconcile this divide by using a continuous behavioural response measure that indexes face processing at a temporal resolution not available in discrete behavioural measures (e.g. button press). Using reaching trajectories as our response measure, we observed that although participants were able to process faces both when attended and unattended (as others have found), face processing was not impervious to attentional modulation. Attending to the face conferred clear benefits on sex-classification processes at less than 350ms of stimulus processing time. These findings constitute the first reliable demonstration of the modulatory effects of both spatial and temporal attention on face processing within a behavioural paradigm.

Show MeSH
Related in: MedlinePlus