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Papers by Nikos Konstantinou

Research paper thumbnail of PanayiotouManuscriptYoungDrivers revision2

Research paper thumbnail of AuthorpreprintAggressiveDriving

Research paper thumbnail of Social anxiety in young adults: Associations with neuroticism and distress

Research paper thumbnail of Working memory load and distraction: dissociable effects of visual maintenance and cognitive control

Attention, Perception, & Psychophysics, 2014

We establish a new dissociation between the roles of working memory (WM) cognitive control and vi... more We establish a new dissociation between the roles of working memory (WM) cognitive control and visual maintenance in selective attention as measured by the efficiency of distractor rejection. The extent to which focused selective attention can prevent distraction has been shown to critically depend on the level and type of load involved in the task. High perceptual load that consumes perceptual capacity leads to reduced distractor processing, whereas high WM load that reduces WM ability to exert priority-based executive cognitive control over the task results in increased distractor processing (e.g., Lavie, Trends in Cognitive Sciences, 9(2), [75][76][77][78][79][80][81][82] 2005). WM also serves to maintain task-relevant visual representations, and such visual maintenance is known to recruit the same sensory cortices as those involved in perception (e.g., Pasternak & Greenlee, Nature Reviews Neuroscience, 6(2), 97-107, 2005). These findings led us to hypothesize that loading WM with visual maintenance would reduce visual capacity involved in perception, thus resulting in reduced distractor processing-similar to perceptual load and opposite to WM cognitive control load. Distractor processing was assessed in a response competition task, presented during the memory interval (or during encoding; Experiment 1a) of a WM task. Loading visual maintenance or encoding by increased set size for a memory sample of shapes, colors, and locations led to reduced distractor response competition effects. In contrast, loading WM cognitive control with verbal rehearsal of a random letter set led to increased distractor effects. These findings confirm load theory predictions and provide a novel functional distinction between the roles of WM maintenance and cognitive control in selective attention.

Research paper thumbnail of Blinded by the load: attention, awareness and the role of perceptual load

Philosophical Transactions of the Royal Society B: Biological Sciences, 2014

Research paper thumbnail of Spatial Working Memory Capacity Estimates Correlate With the Structure of Frontal and Parietal Cortex

Research paper thumbnail of Dissociable roles of different types of working memory load in visual detection

Journal of Experimental Psychology: Human Perception and Performance, 2013

We contrasted the effects of different types of working memory (WM) load on detection. Considerin... more We contrasted the effects of different types of working memory (WM) load on detection. Considering the sensory-recruitment hypothesis of visual short-term memory (VSTM) within load theory (e.g., Lavie, 2010) led us to predict that VSTM load would reduce visual-representation capacity, thus leading to reduced detection sensitivity during maintenance, whereas load on WM cognitive control processes would reduce priority-based control, thus leading to enhanced detection sensitivity for a low-priority stimulus. During the retention interval of a WM task, participants performed a visual-search task while also asked to detect a masked stimulus in the periphery. Loading WM cognitive control processes (with the demand to maintain a random digit order [vs. fixed in conditions of low load]) led to enhanced detection sensitivity. In contrast, loading VSTM (with the demand to maintain the color and positions of six squares [vs. one in conditions of low load]) reduced detection sensitivity, an effect comparable with that found for manipulating perceptual load in the search task. The results confirmed our predictions and established a new functional dissociation between the roles of different types of WM load in the fundamental visual perception process of detection.

Research paper thumbnail of The role of visual short term memory load in visual sensory detection

In this thesis I established the role of Visual Short-Term Memory (VSTM) load in visual detection... more In this thesis I established the role of Visual Short-Term Memory (VSTM) load in visual detection while comparing to the roles of perceptual load and Working Memory (WM) cognitive control load. Participants performed a short-term memory task combined with a visual detection task (as well as attention task, Chapter 2) during the memory delay. The level and type of load was varied (perceptual load, VSTM load or WM cognitive control load). Measures of detection sensitivity demonstrated that increased VSTM load and perceptual ...

Research paper thumbnail of The relationship between executive functioning, working memory and speed of processing

Research paper thumbnail of Risky and aggressive driving in young adults: Personality matters

Accident Analysis and Prevention, 2011

Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road... more Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road traffic accidents around the world. This study, attempts to identify motivational factors behind risky driving behavior, and examines the role of personality, especially sensation seeking, impulsivity and sensitivity to punishment/reward in predicting negative driving outcomes (accident involvement and traffic offenses) among young drivers.

Research paper thumbnail of Risky and aggressive driving in young adults: Personality matters

Accident Analysis and Prevention, 2011

Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road... more Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road traffic accidents around the world. This study, attempts to identify motivational factors behind risky driving behavior, and examines the role of personality, especially sensation seeking, impulsivity and sensitivity to punishment/reward in predicting negative driving outcomes (accident involvement and traffic offences) among young drivers. Gender and driver's age are additional factors examined in relation to driving outcomes and personality. Adopting the contextual mediated model of traffic accident involvement , the study is based on the theory that personality, age and gender represent distal factors that predict accident involvement indirectly through their relationship with stable tendencies towards aberrant driving behavior. Results from correlations and Structural Equation Modeling using AMOS 6 indicated that direct personality effects on driving outcomes were few, whereas personality had significant correlations with aberrant driving behavior, showing that personality is a distal but important predictor of negative driving outcomes. These high risk traits appear to be at a peak among young male drivers. Thus, personality is important in understanding aggressive and risky driving by young adults and needs to be taken into consideration in designing targeted accident prevention policies.

Research paper thumbnail of Visual Short-term Memory Load Reduces Retinotopic Cortex Response to Contrast

Journal of Cognitive Neuroscience

Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory vi... more Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory visual cortex response to task-unrelated stimuli resulting in "load-induced blindness" [e.g., Lavie, N. Attention, distraction and cognitive control under load. Current Directions in Psychological Science, 19, 143-148, 2010; Lavie, N. Distracted and confused?: Selective attention under load. Trends in Cognitive Sciences, 9, 75-82, 2005]. Consideration of the findings that visual STM (VSTM) involves sensory recruitment [e.g., Pasternak, T., & Greenlee, M. Working memory in primate sensory systems. Nature Reviews Neuroscience, 6, 97-107, 2005] within Load Theory led us to a new hypothesis regarding the effects of VSTM load on visual processing. If VSTM load draws on sensory visual capacity, then similar to perceptual load, high VSTM load should also reduce visual cortex response to incoming stimuli leading to a failure to detect them. We tested this hypothesis with fMRI and behavioral measures of visual detection sensitivity. Participants detected the presence of a contrast increment during the maintenance delay in a VSTM task requiring maintenance of color and position. Increased VSTM load (manipulated by increased set size) led to reduced retinotopic visual cortex (V1-V3) responses to contrast as well as reduced detection sensitivity, as we predicted. Additional visual detection experiments established a clear tradeoff between the amount of information maintained in VSTM and detection sensitivity, while ruling out alternative accounts for the effects of VSTM load in terms of differential spatial allocation strategies or task difficulty. These findings extend Load Theory to demonstrate a new form of competitive interactions between early visual cortex processing and visual representations held in memory under load and provide a novel line of support for the sensory recruitment hypothesis of VSTM.

Research paper thumbnail of Visual Short-Term Memory Load Induced Blindness

Journal of Vision, 2010

Abstract We present imaging and behavioral experiments, establishing that visual short-term memor... more Abstract We present imaging and behavioral experiments, establishing that visual short-term memory (VSTM) load, similar to perceptual load (eg Macdonald and Lavie (2008), but opposite to task-unrelated verbal working memory load (see Konstantinou & Lavie, 2010), can reduce both detection sensitivity (d') and the related signal in V1 for peripheral stimuli presented during the memory delay. Participants in the fMRI scanner were required to maintain the color and position of a memory set (consisting of colored squares) and detect ...

Research paper thumbnail of PanayiotouManuscriptYoungDrivers revision2

Research paper thumbnail of AuthorpreprintAggressiveDriving

Research paper thumbnail of Social anxiety in young adults: Associations with neuroticism and distress

Research paper thumbnail of Working memory load and distraction: dissociable effects of visual maintenance and cognitive control

Attention, Perception, & Psychophysics, 2014

We establish a new dissociation between the roles of working memory (WM) cognitive control and vi... more We establish a new dissociation between the roles of working memory (WM) cognitive control and visual maintenance in selective attention as measured by the efficiency of distractor rejection. The extent to which focused selective attention can prevent distraction has been shown to critically depend on the level and type of load involved in the task. High perceptual load that consumes perceptual capacity leads to reduced distractor processing, whereas high WM load that reduces WM ability to exert priority-based executive cognitive control over the task results in increased distractor processing (e.g., Lavie, Trends in Cognitive Sciences, 9(2), [75][76][77][78][79][80][81][82] 2005). WM also serves to maintain task-relevant visual representations, and such visual maintenance is known to recruit the same sensory cortices as those involved in perception (e.g., Pasternak & Greenlee, Nature Reviews Neuroscience, 6(2), 97-107, 2005). These findings led us to hypothesize that loading WM with visual maintenance would reduce visual capacity involved in perception, thus resulting in reduced distractor processing-similar to perceptual load and opposite to WM cognitive control load. Distractor processing was assessed in a response competition task, presented during the memory interval (or during encoding; Experiment 1a) of a WM task. Loading visual maintenance or encoding by increased set size for a memory sample of shapes, colors, and locations led to reduced distractor response competition effects. In contrast, loading WM cognitive control with verbal rehearsal of a random letter set led to increased distractor effects. These findings confirm load theory predictions and provide a novel functional distinction between the roles of WM maintenance and cognitive control in selective attention.

Research paper thumbnail of Blinded by the load: attention, awareness and the role of perceptual load

Philosophical Transactions of the Royal Society B: Biological Sciences, 2014

Research paper thumbnail of Spatial Working Memory Capacity Estimates Correlate With the Structure of Frontal and Parietal Cortex

Research paper thumbnail of Dissociable roles of different types of working memory load in visual detection

Journal of Experimental Psychology: Human Perception and Performance, 2013

We contrasted the effects of different types of working memory (WM) load on detection. Considerin... more We contrasted the effects of different types of working memory (WM) load on detection. Considering the sensory-recruitment hypothesis of visual short-term memory (VSTM) within load theory (e.g., Lavie, 2010) led us to predict that VSTM load would reduce visual-representation capacity, thus leading to reduced detection sensitivity during maintenance, whereas load on WM cognitive control processes would reduce priority-based control, thus leading to enhanced detection sensitivity for a low-priority stimulus. During the retention interval of a WM task, participants performed a visual-search task while also asked to detect a masked stimulus in the periphery. Loading WM cognitive control processes (with the demand to maintain a random digit order [vs. fixed in conditions of low load]) led to enhanced detection sensitivity. In contrast, loading VSTM (with the demand to maintain the color and positions of six squares [vs. one in conditions of low load]) reduced detection sensitivity, an effect comparable with that found for manipulating perceptual load in the search task. The results confirmed our predictions and established a new functional dissociation between the roles of different types of WM load in the fundamental visual perception process of detection.

Research paper thumbnail of The role of visual short term memory load in visual sensory detection

In this thesis I established the role of Visual Short-Term Memory (VSTM) load in visual detection... more In this thesis I established the role of Visual Short-Term Memory (VSTM) load in visual detection while comparing to the roles of perceptual load and Working Memory (WM) cognitive control load. Participants performed a short-term memory task combined with a visual detection task (as well as attention task, Chapter 2) during the memory delay. The level and type of load was varied (perceptual load, VSTM load or WM cognitive control load). Measures of detection sensitivity demonstrated that increased VSTM load and perceptual ...

Research paper thumbnail of The relationship between executive functioning, working memory and speed of processing

Research paper thumbnail of Risky and aggressive driving in young adults: Personality matters

Accident Analysis and Prevention, 2011

Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road... more Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road traffic accidents around the world. This study, attempts to identify motivational factors behind risky driving behavior, and examines the role of personality, especially sensation seeking, impulsivity and sensitivity to punishment/reward in predicting negative driving outcomes (accident involvement and traffic offenses) among young drivers.

Research paper thumbnail of Risky and aggressive driving in young adults: Personality matters

Accident Analysis and Prevention, 2011

Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road... more Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road traffic accidents around the world. This study, attempts to identify motivational factors behind risky driving behavior, and examines the role of personality, especially sensation seeking, impulsivity and sensitivity to punishment/reward in predicting negative driving outcomes (accident involvement and traffic offences) among young drivers. Gender and driver's age are additional factors examined in relation to driving outcomes and personality. Adopting the contextual mediated model of traffic accident involvement , the study is based on the theory that personality, age and gender represent distal factors that predict accident involvement indirectly through their relationship with stable tendencies towards aberrant driving behavior. Results from correlations and Structural Equation Modeling using AMOS 6 indicated that direct personality effects on driving outcomes were few, whereas personality had significant correlations with aberrant driving behavior, showing that personality is a distal but important predictor of negative driving outcomes. These high risk traits appear to be at a peak among young male drivers. Thus, personality is important in understanding aggressive and risky driving by young adults and needs to be taken into consideration in designing targeted accident prevention policies.

Research paper thumbnail of Visual Short-term Memory Load Reduces Retinotopic Cortex Response to Contrast

Journal of Cognitive Neuroscience

Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory vi... more Load Theory of attention suggests that high perceptual load in a task leads to reduced sensory visual cortex response to task-unrelated stimuli resulting in "load-induced blindness" [e.g., Lavie, N. Attention, distraction and cognitive control under load. Current Directions in Psychological Science, 19, 143-148, 2010; Lavie, N. Distracted and confused?: Selective attention under load. Trends in Cognitive Sciences, 9, 75-82, 2005]. Consideration of the findings that visual STM (VSTM) involves sensory recruitment [e.g., Pasternak, T., & Greenlee, M. Working memory in primate sensory systems. Nature Reviews Neuroscience, 6, 97-107, 2005] within Load Theory led us to a new hypothesis regarding the effects of VSTM load on visual processing. If VSTM load draws on sensory visual capacity, then similar to perceptual load, high VSTM load should also reduce visual cortex response to incoming stimuli leading to a failure to detect them. We tested this hypothesis with fMRI and behavioral measures of visual detection sensitivity. Participants detected the presence of a contrast increment during the maintenance delay in a VSTM task requiring maintenance of color and position. Increased VSTM load (manipulated by increased set size) led to reduced retinotopic visual cortex (V1-V3) responses to contrast as well as reduced detection sensitivity, as we predicted. Additional visual detection experiments established a clear tradeoff between the amount of information maintained in VSTM and detection sensitivity, while ruling out alternative accounts for the effects of VSTM load in terms of differential spatial allocation strategies or task difficulty. These findings extend Load Theory to demonstrate a new form of competitive interactions between early visual cortex processing and visual representations held in memory under load and provide a novel line of support for the sensory recruitment hypothesis of VSTM.

Research paper thumbnail of Visual Short-Term Memory Load Induced Blindness

Journal of Vision, 2010

Abstract We present imaging and behavioral experiments, establishing that visual short-term memor... more Abstract We present imaging and behavioral experiments, establishing that visual short-term memory (VSTM) load, similar to perceptual load (eg Macdonald and Lavie (2008), but opposite to task-unrelated verbal working memory load (see Konstantinou & Lavie, 2010), can reduce both detection sensitivity (d') and the related signal in V1 for peripheral stimuli presented during the memory delay. Participants in the fMRI scanner were required to maintain the color and position of a memory set (consisting of colored squares) and detect ...