In an ever-changing environment, survival depends on learning which stimuli represent threat, and... more In an ever-changing environment, survival depends on learning which stimuli represent threat, and also on updating such associations when circumstances shift. It has been claimed that humans can acquire physiological responses to threat-associated stimuli even when they are unaware of them, but the role of awareness in updating threat contingencies remains unknown. This complex process—generating novel responses while suppressing learned ones—relies on distinct neural mechanisms from initial learning, and has only been shown with awareness. Can it occur unconsciously? Here, we present evidence that threat reversal may not require awareness. Participants underwent classical threat conditioning to visual stimuli that were suppressed from awareness. One of two images was paired with an electric shock; halfway through the experiment, contingencies were reversed and the shock was paired with the other image. Despite variations in suppression across participants, we found that physiologic...
ABSTRACTHuman vision is sensitive enough to detect a single photon, but the minimal exposure requ... more ABSTRACTHuman vision is sensitive enough to detect a single photon, but the minimal exposure required to extractmeaningfrom stimulation – arguably the visual system’s function – remains unknown. This requirement cannot be characterised in terms of stimulus energy, because the system is differentially sensitive to attributes that are distinguished by stimulus configuration rather than physical amplitude. Observers can extract large amounts of information from brief displays; but for given display durations, certain types of information are discerned more readily than others, suggesting that visual pathways prioritise certain stimulus properties. Determining theminimalexposure durations required for processing various aspects of a visual stimulus can thus shed light on the system’s priorities. Technical limitations have so far prevented measurement of such minima; here, we used a novel technique enabling arbitrarily brief displays with microsecond-level precision to establish the mini...
Abstract When visual input has conflicting interpretations, conscious perception may alternate sp... more Abstract When visual input has conflicting interpretations, conscious perception may alternate spontaneously between them. There is a large amount of unexplained variability between individuals in the rate of perceptual switches. We investigated whether variability in perceptual rivalry is reflected in individual differences in brain structure. To do so, we collected perceptual switch rates for a structure-from-motion (SFM) stimulus from a group of 52 participants and examined whether variability in brain structure across participants ...
Understanding faces and their emotional expressions is essential for social interaction. Past stu... more Understanding faces and their emotional expressions is essential for social interaction. Past studies have prompted suggestions that some facial features may be processed unconsciously. Evidence for such unconscious processing has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For instance, it has been claimed that suppressed fearful expressions are detected faster that neutral expressions. However, in the b-CFS procedure, observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we use a procedure that addresses these problems by using predefined exposure durations and measuring sensitivity and decision criteria for both detection and identification of facial expressions. We found that neither angry nor fearful e...
ABSTRACT We are conscious beings: Somehow, the activity of our brains and nervous systems gives r... more ABSTRACT We are conscious beings: Somehow, the activity of our brains and nervous systems gives rise to states in which we have subjective experiences; and when we are in such states, we are aware of specific content. Researchers are only beginning to develop an understanding of the neural mechanisms underlying these phenomena. Much of the research in the last few decades has focussed on discerning the neural correlates of consciousness, using neuroimaging methods. Correlates, however, are not causes: to draw inferences about the processes that generate consciousness, rather than accompanying it, one must manipulate brain activity and examine the effects this has on conscious states and contents. One way to do so is to use brain stimulation techniques, such as transcranial magnetic stimulation (TMS). In this review, we survey the consciousness literature with a special emphasis on TMS studies. We begin by examining what is known about the neural substrates of states of consciousness – the kinds of brain activity that determine whether a person is awake, asleep, or suffering from a disorder of consciousness. We then delve into the contents of consciousness, by examining the literature on perceptual awareness. Throughout, we highlight current controversies and promising avenues for further research.
Faces convey a wealth of information essential for social interaction. Their importance has promp... more Faces convey a wealth of information essential for social interaction. Their importance has prompted suggestions that some facial features may even be processed unconsciously. Evidence for such unconscious processing has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For instance, suppressed upright faces and faces making eye contact are detected faster than inverted faces and faces looking away, respectively. However, the b-CFS procedure suffers from important problems: Observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we first replicated gaze-direction and face-orientation b-CFS effects, and then developed a new procedure that addresses these problems by using predefined exposure durations and measuring ...
Recent replication crises in psychology and other fields have led to intense reflection about the... more Recent replication crises in psychology and other fields have led to intense reflection about the validity of common research practices. Much of this reflection has focussed on reporting standards, and how they may be related to the questionable research practices that could underlie a high proportion of irreproducible findings in the published record. As a developing field, it is particularly important for Experimental Philosophy to avoid some of the pitfalls that have beset other disciplines. To this end, here we provide a detailed, comprehensive assessment of current reporting practices in Experimental Philosophy. We focus on the quality of statistical reporting and the disclosure of information about study methodology. We assess all the articles using quantitative methods (n = 134) that were published over the years 2013–2016 in 29 leading philosophy journals. We find that null hypothesis significance testing is the prevalent statistical practice in Experimental Philosophy, alth...
In an ever-changing environment, survival depends on learning which stimuli represent threat, and... more In an ever-changing environment, survival depends on learning which stimuli represent threat, and also on updating such associations when circumstances shift. Humans can acquire physiological responses to threat-associated stimuli even when they are unaware of them, but the role of awareness in updating threat contingencies remains unknown. This complex process – generating novel responses while simultaneously suppressing learned ones – relies on distinct neural mechanisms from initial learning, and has only been shown with awareness. Can it occur unconsciously? Here we show that it can. Participants underwent classical threat conditioning to visual stimuli that were suppressed from their awareness. One of two images was paired with an electric shock; halfway through the experiment, contingencies were reversed and the shock was paired with the other image. We found that physiological responses reflected changes in stimulus-threat pairings independently of stimulus awareness, demonst...
Cognitive, Affective, & Behavioral Neuroscience, 2018
Attention is biased toward emotional stimuli, even when they are irrelevant to current goals. Mot... more Attention is biased toward emotional stimuli, even when they are irrelevant to current goals. Motivation, elicited by performancecontingent reward, reduces behavioural emotional distraction. In emotionally neutral contexts, reward is thought to encourage use of a proactive cognitive control strategy, altering anticipatory attentional settings to more effectively suppress distractors. The current preregistered study investigates whether a similar proactive shift occurs even when distractors are highly arousing emotional images. We monitored pupil area, an online measure of both cognitive and emotional processing, to examine how reward influences the time course of control. Participants (n = 110) identified a target letter flanking an irrelevant central image. Images were meaningless scrambles on 75% of trials; on the remaining 25%, they were intact positive (erotic), negative (mutilation), or neutral images. Half the participants received financial rewards for fast and accurate performance, while the other half received no performance-contingent reward. Emotional distraction was greater than neutral distraction, and both were attenuated by reward. Consistent with behavioural findings, pupil dilation was greater following emotional than neutral distractors, and dilation to intact distractors (regardless of valence) was decreased by reward. Although reward did not enhance tonic pupil dilation (an index of sustained proactive control), exploratory analyses showed that reward altered the time course of control-eliciting a sharp, rapid, increase in dilation immediately preceding stimulus onset (reflecting dynamic use of anticipatory control), that extended until well after stimulus offset. These findings suggest that reward alters the time course of control by encouraging proactive preparation to rapidly disengage from emotional distractors.
Is consciousness required for high level cognitive processes, or can the unconscious mind perform... more Is consciousness required for high level cognitive processes, or can the unconscious mind perform tasks that are as complex and difficult as, for example, understanding a sentence? Recent work has argued that, yes, the unconscious mind can: Sklar et al. (2012) found that sentences, masked from consciousness using the technique of continuous flash suppression (CFS), broke into awareness more rapidly when their meanings were more unusual or more emotionally negative, even though processing the sentences' meaning required unconsciously combining each word's meaning. This has motivated the important claim that consciousness plays little-to-no functional role in high-level cognitive operations. Here, we aimed to replicate and extend these findings, but instead, across 10 high-powered studies, we found no evidence that the meaning of a phrase or word could be understood without awareness. We did, however, consistently find evidence that low-level perceptual features, such as sente...
Conscious emotional processing is characterized by a coordinated set of responses across multiple... more Conscious emotional processing is characterized by a coordinated set of responses across multiple physiological systems. Although emotional stimuli can evoke certain physiological responses even when they are suppressed from awareness, it is not known whether unconscious emotional responses comprise a similar constellation or are confined to specific systems. To compare physiological responses to emotional stimuli with and without awareness, we measured a range of responses while participants viewed positive, negative and neutral images that were accompanied by noise bursts to elicit startle reflexes. We measured four responses simultaneously - skin conductance and heart rate changes in response to the images themselves; and startle eye-blink and post-auricular reflexes in response to the noise bursts that occurred during image presentation. For half of the participants, the images were masked from awareness using continuous flash suppression. The aware group showed the expected pat...
The dynamics of perceptual bistability, the phenomenon in which perception switches between diffe... more The dynamics of perceptual bistability, the phenomenon in which perception switches between different interpretations of an unchanging stimulus, are characterised by very similar properties across a wide range of qualitatively different paradigms. This suggests that perceptual switching may be triggered by some common source. However, it is also possible that perceptual switching may arise from a distributed system, whose components vary according to the specifics of the perceptual experiences involved. Here we used a visual and an auditory task to determine whether individuals show cross-modal commonalities in perceptual switching. We found that individual perceptual switching rates were significantly correlated across modalities. We then asked whether perceptual switching arises from some central (modality-) task-independent process or from a more distributed task-specific system. We found that a log-normal distribution best explained the distribution of perceptual phases in both ...
Attending to emotional stimuli is often beneficial, because they provide important social and env... more Attending to emotional stimuli is often beneficial, because they provide important social and environmental cues. Sometimes, however, current goals require that we ignore them. To what extent can we control emotional distraction? Here we show that the ability to ignore emotional distractions depends on the type of cognitive control that is engaged. Participants completed a simple perceptual task at fixation while irrelevant images appeared peripherally. In 2 experiments, we manipulated the proportion of trials in which images appeared, to encourage use of either reactive control (rare distractors) or proactive control (frequent distractors). Under reactive control, both negative and positive images were more distracting than neutral images, even though they were irrelevant and appeared in unattended locations. However, under proactive control, distraction by both emotional and neutral images was eliminated. Proactive control was triggered by the meaning, and not the location, of dis...
This is a book manuscript suggesting a new theory of free will. I am about to start contacting pu... more This is a book manuscript suggesting a new theory of free will. I am about to start contacting publishers, but before that I am happy to hear any comments - please send an e-mail to Atle.O.Sovik@mf.no
Does the brain activity underlying the production of deception differ depending on whether or not... more Does the brain activity underlying the production of deception differ depending on whether or not one believes their deception can be detected? To address this question, we had participants commit a mock theft in a laboratory setting, and then interrogated them while they underwent functional MRI (fMRI) scanning. Crucially, during some parts of the interrogation participants believed a lie-detector was activated, whereas in other parts they were told it was switched-off. We were thus able to examine the neural activity associated with the contrast between producing true vs. false claims, as well as the independent contrast between believing that deception could and could not be detected. We found increased activation in the right amygdala and inferior frontal gyrus (IFG), as well as the left posterior cingulate cortex (PCC), during the production of false (compared to true) claims. Importantly, there was a significant interaction between the effects of deception and belief in the le...
Abstract Goal: Perceptual learning (PL), training-induced perceptual improvement, is usually high... more Abstract Goal: Perceptual learning (PL), training-induced perceptual improvement, is usually highly specific, limited to trained locations or features. Previously, we reported that covert attention helps generalize PL to an adjacent, attended location (VSS 2009). Here we examined the effect of attention on PL at attended locations as well as unattended locations in a different quadrant of the visual field. Procedure: Participants performed an orientation discrimination task, indicating whether a briefly-presented Gabor patch of variable contrast ...
Abstract How do conscious and unconscious visual processing differ? Suppressing visual stimuli fr... more Abstract How do conscious and unconscious visual processing differ? Suppressing visual stimuli from awareness has previously revealed quantitative differences, either reducing or eradicating their processing. Finding qualitative differences, however, would further benefit the understanding of systems mediating conscious versus unconscious processing. Here, we show such a difference in the timing of conscious and unconscious fear acquisition, an essential function for adaptive behavior. Threatening stimuli can be detected, and the fear ...
Journal of Experimental Psychology: Human Perception and Performance, 2011
Increasing perceptual load reduces the processing of visual stimuli outside the focus of attentio... more Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load should affect simultaneous, but not sequential, stimulus presentations, the visual excitability account makes the novel prediction that load should affect detection sensitivity for both simultaneous and sequential presentations. Participants fixated a stimulus stream, responding to targets defined by either a color (low load) or color and orientation conjunctions (high load). Additionally, detection sensitivity was measured for a peripheral critical stimulus (CS) presented occasionally. Increasing load at fixation reduced sensitivity to the peripheral CSs; this effect was similar regardless of whether CSs were presented simultaneously with central stimuli or during the (otherwise empty) interval between them. Controls ruled out explanations of the results in terms of strategic task prioritization. These findings support a cortical excitability account for perceptual load, challenging stimulus competition accounts.
In an ever-changing environment, survival depends on learning which stimuli represent threat, and... more In an ever-changing environment, survival depends on learning which stimuli represent threat, and also on updating such associations when circumstances shift. It has been claimed that humans can acquire physiological responses to threat-associated stimuli even when they are unaware of them, but the role of awareness in updating threat contingencies remains unknown. This complex process—generating novel responses while suppressing learned ones—relies on distinct neural mechanisms from initial learning, and has only been shown with awareness. Can it occur unconsciously? Here, we present evidence that threat reversal may not require awareness. Participants underwent classical threat conditioning to visual stimuli that were suppressed from awareness. One of two images was paired with an electric shock; halfway through the experiment, contingencies were reversed and the shock was paired with the other image. Despite variations in suppression across participants, we found that physiologic...
ABSTRACTHuman vision is sensitive enough to detect a single photon, but the minimal exposure requ... more ABSTRACTHuman vision is sensitive enough to detect a single photon, but the minimal exposure required to extractmeaningfrom stimulation – arguably the visual system’s function – remains unknown. This requirement cannot be characterised in terms of stimulus energy, because the system is differentially sensitive to attributes that are distinguished by stimulus configuration rather than physical amplitude. Observers can extract large amounts of information from brief displays; but for given display durations, certain types of information are discerned more readily than others, suggesting that visual pathways prioritise certain stimulus properties. Determining theminimalexposure durations required for processing various aspects of a visual stimulus can thus shed light on the system’s priorities. Technical limitations have so far prevented measurement of such minima; here, we used a novel technique enabling arbitrarily brief displays with microsecond-level precision to establish the mini...
Abstract When visual input has conflicting interpretations, conscious perception may alternate sp... more Abstract When visual input has conflicting interpretations, conscious perception may alternate spontaneously between them. There is a large amount of unexplained variability between individuals in the rate of perceptual switches. We investigated whether variability in perceptual rivalry is reflected in individual differences in brain structure. To do so, we collected perceptual switch rates for a structure-from-motion (SFM) stimulus from a group of 52 participants and examined whether variability in brain structure across participants ...
Understanding faces and their emotional expressions is essential for social interaction. Past stu... more Understanding faces and their emotional expressions is essential for social interaction. Past studies have prompted suggestions that some facial features may be processed unconsciously. Evidence for such unconscious processing has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For instance, it has been claimed that suppressed fearful expressions are detected faster that neutral expressions. However, in the b-CFS procedure, observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we use a procedure that addresses these problems by using predefined exposure durations and measuring sensitivity and decision criteria for both detection and identification of facial expressions. We found that neither angry nor fearful e...
ABSTRACT We are conscious beings: Somehow, the activity of our brains and nervous systems gives r... more ABSTRACT We are conscious beings: Somehow, the activity of our brains and nervous systems gives rise to states in which we have subjective experiences; and when we are in such states, we are aware of specific content. Researchers are only beginning to develop an understanding of the neural mechanisms underlying these phenomena. Much of the research in the last few decades has focussed on discerning the neural correlates of consciousness, using neuroimaging methods. Correlates, however, are not causes: to draw inferences about the processes that generate consciousness, rather than accompanying it, one must manipulate brain activity and examine the effects this has on conscious states and contents. One way to do so is to use brain stimulation techniques, such as transcranial magnetic stimulation (TMS). In this review, we survey the consciousness literature with a special emphasis on TMS studies. We begin by examining what is known about the neural substrates of states of consciousness – the kinds of brain activity that determine whether a person is awake, asleep, or suffering from a disorder of consciousness. We then delve into the contents of consciousness, by examining the literature on perceptual awareness. Throughout, we highlight current controversies and promising avenues for further research.
Faces convey a wealth of information essential for social interaction. Their importance has promp... more Faces convey a wealth of information essential for social interaction. Their importance has prompted suggestions that some facial features may even be processed unconsciously. Evidence for such unconscious processing has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For instance, suppressed upright faces and faces making eye contact are detected faster than inverted faces and faces looking away, respectively. However, the b-CFS procedure suffers from important problems: Observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we first replicated gaze-direction and face-orientation b-CFS effects, and then developed a new procedure that addresses these problems by using predefined exposure durations and measuring ...
Recent replication crises in psychology and other fields have led to intense reflection about the... more Recent replication crises in psychology and other fields have led to intense reflection about the validity of common research practices. Much of this reflection has focussed on reporting standards, and how they may be related to the questionable research practices that could underlie a high proportion of irreproducible findings in the published record. As a developing field, it is particularly important for Experimental Philosophy to avoid some of the pitfalls that have beset other disciplines. To this end, here we provide a detailed, comprehensive assessment of current reporting practices in Experimental Philosophy. We focus on the quality of statistical reporting and the disclosure of information about study methodology. We assess all the articles using quantitative methods (n = 134) that were published over the years 2013–2016 in 29 leading philosophy journals. We find that null hypothesis significance testing is the prevalent statistical practice in Experimental Philosophy, alth...
In an ever-changing environment, survival depends on learning which stimuli represent threat, and... more In an ever-changing environment, survival depends on learning which stimuli represent threat, and also on updating such associations when circumstances shift. Humans can acquire physiological responses to threat-associated stimuli even when they are unaware of them, but the role of awareness in updating threat contingencies remains unknown. This complex process – generating novel responses while simultaneously suppressing learned ones – relies on distinct neural mechanisms from initial learning, and has only been shown with awareness. Can it occur unconsciously? Here we show that it can. Participants underwent classical threat conditioning to visual stimuli that were suppressed from their awareness. One of two images was paired with an electric shock; halfway through the experiment, contingencies were reversed and the shock was paired with the other image. We found that physiological responses reflected changes in stimulus-threat pairings independently of stimulus awareness, demonst...
Cognitive, Affective, & Behavioral Neuroscience, 2018
Attention is biased toward emotional stimuli, even when they are irrelevant to current goals. Mot... more Attention is biased toward emotional stimuli, even when they are irrelevant to current goals. Motivation, elicited by performancecontingent reward, reduces behavioural emotional distraction. In emotionally neutral contexts, reward is thought to encourage use of a proactive cognitive control strategy, altering anticipatory attentional settings to more effectively suppress distractors. The current preregistered study investigates whether a similar proactive shift occurs even when distractors are highly arousing emotional images. We monitored pupil area, an online measure of both cognitive and emotional processing, to examine how reward influences the time course of control. Participants (n = 110) identified a target letter flanking an irrelevant central image. Images were meaningless scrambles on 75% of trials; on the remaining 25%, they were intact positive (erotic), negative (mutilation), or neutral images. Half the participants received financial rewards for fast and accurate performance, while the other half received no performance-contingent reward. Emotional distraction was greater than neutral distraction, and both were attenuated by reward. Consistent with behavioural findings, pupil dilation was greater following emotional than neutral distractors, and dilation to intact distractors (regardless of valence) was decreased by reward. Although reward did not enhance tonic pupil dilation (an index of sustained proactive control), exploratory analyses showed that reward altered the time course of control-eliciting a sharp, rapid, increase in dilation immediately preceding stimulus onset (reflecting dynamic use of anticipatory control), that extended until well after stimulus offset. These findings suggest that reward alters the time course of control by encouraging proactive preparation to rapidly disengage from emotional distractors.
Is consciousness required for high level cognitive processes, or can the unconscious mind perform... more Is consciousness required for high level cognitive processes, or can the unconscious mind perform tasks that are as complex and difficult as, for example, understanding a sentence? Recent work has argued that, yes, the unconscious mind can: Sklar et al. (2012) found that sentences, masked from consciousness using the technique of continuous flash suppression (CFS), broke into awareness more rapidly when their meanings were more unusual or more emotionally negative, even though processing the sentences' meaning required unconsciously combining each word's meaning. This has motivated the important claim that consciousness plays little-to-no functional role in high-level cognitive operations. Here, we aimed to replicate and extend these findings, but instead, across 10 high-powered studies, we found no evidence that the meaning of a phrase or word could be understood without awareness. We did, however, consistently find evidence that low-level perceptual features, such as sente...
Conscious emotional processing is characterized by a coordinated set of responses across multiple... more Conscious emotional processing is characterized by a coordinated set of responses across multiple physiological systems. Although emotional stimuli can evoke certain physiological responses even when they are suppressed from awareness, it is not known whether unconscious emotional responses comprise a similar constellation or are confined to specific systems. To compare physiological responses to emotional stimuli with and without awareness, we measured a range of responses while participants viewed positive, negative and neutral images that were accompanied by noise bursts to elicit startle reflexes. We measured four responses simultaneously - skin conductance and heart rate changes in response to the images themselves; and startle eye-blink and post-auricular reflexes in response to the noise bursts that occurred during image presentation. For half of the participants, the images were masked from awareness using continuous flash suppression. The aware group showed the expected pat...
The dynamics of perceptual bistability, the phenomenon in which perception switches between diffe... more The dynamics of perceptual bistability, the phenomenon in which perception switches between different interpretations of an unchanging stimulus, are characterised by very similar properties across a wide range of qualitatively different paradigms. This suggests that perceptual switching may be triggered by some common source. However, it is also possible that perceptual switching may arise from a distributed system, whose components vary according to the specifics of the perceptual experiences involved. Here we used a visual and an auditory task to determine whether individuals show cross-modal commonalities in perceptual switching. We found that individual perceptual switching rates were significantly correlated across modalities. We then asked whether perceptual switching arises from some central (modality-) task-independent process or from a more distributed task-specific system. We found that a log-normal distribution best explained the distribution of perceptual phases in both ...
Attending to emotional stimuli is often beneficial, because they provide important social and env... more Attending to emotional stimuli is often beneficial, because they provide important social and environmental cues. Sometimes, however, current goals require that we ignore them. To what extent can we control emotional distraction? Here we show that the ability to ignore emotional distractions depends on the type of cognitive control that is engaged. Participants completed a simple perceptual task at fixation while irrelevant images appeared peripherally. In 2 experiments, we manipulated the proportion of trials in which images appeared, to encourage use of either reactive control (rare distractors) or proactive control (frequent distractors). Under reactive control, both negative and positive images were more distracting than neutral images, even though they were irrelevant and appeared in unattended locations. However, under proactive control, distraction by both emotional and neutral images was eliminated. Proactive control was triggered by the meaning, and not the location, of dis...
This is a book manuscript suggesting a new theory of free will. I am about to start contacting pu... more This is a book manuscript suggesting a new theory of free will. I am about to start contacting publishers, but before that I am happy to hear any comments - please send an e-mail to Atle.O.Sovik@mf.no
Does the brain activity underlying the production of deception differ depending on whether or not... more Does the brain activity underlying the production of deception differ depending on whether or not one believes their deception can be detected? To address this question, we had participants commit a mock theft in a laboratory setting, and then interrogated them while they underwent functional MRI (fMRI) scanning. Crucially, during some parts of the interrogation participants believed a lie-detector was activated, whereas in other parts they were told it was switched-off. We were thus able to examine the neural activity associated with the contrast between producing true vs. false claims, as well as the independent contrast between believing that deception could and could not be detected. We found increased activation in the right amygdala and inferior frontal gyrus (IFG), as well as the left posterior cingulate cortex (PCC), during the production of false (compared to true) claims. Importantly, there was a significant interaction between the effects of deception and belief in the le...
Abstract Goal: Perceptual learning (PL), training-induced perceptual improvement, is usually high... more Abstract Goal: Perceptual learning (PL), training-induced perceptual improvement, is usually highly specific, limited to trained locations or features. Previously, we reported that covert attention helps generalize PL to an adjacent, attended location (VSS 2009). Here we examined the effect of attention on PL at attended locations as well as unattended locations in a different quadrant of the visual field. Procedure: Participants performed an orientation discrimination task, indicating whether a briefly-presented Gabor patch of variable contrast ...
Abstract How do conscious and unconscious visual processing differ? Suppressing visual stimuli fr... more Abstract How do conscious and unconscious visual processing differ? Suppressing visual stimuli from awareness has previously revealed quantitative differences, either reducing or eradicating their processing. Finding qualitative differences, however, would further benefit the understanding of systems mediating conscious versus unconscious processing. Here, we show such a difference in the timing of conscious and unconscious fear acquisition, an essential function for adaptive behavior. Threatening stimuli can be detected, and the fear ...
Journal of Experimental Psychology: Human Perception and Performance, 2011
Increasing perceptual load reduces the processing of visual stimuli outside the focus of attentio... more Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load should affect simultaneous, but not sequential, stimulus presentations, the visual excitability account makes the novel prediction that load should affect detection sensitivity for both simultaneous and sequential presentations. Participants fixated a stimulus stream, responding to targets defined by either a color (low load) or color and orientation conjunctions (high load). Additionally, detection sensitivity was measured for a peripheral critical stimulus (CS) presented occasionally. Increasing load at fixation reduced sensitivity to the peripheral CSs; this effect was similar regardless of whether CSs were presented simultaneously with central stimuli or during the (otherwise empty) interval between them. Controls ruled out explanations of the results in terms of strategic task prioritization. These findings support a cortical excitability account for perceptual load, challenging stimulus competition accounts.
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