Key publications
Elchlepp H, Verbruggen F (2017). How to withhold or replace a prepotent response: an analysis of the underlying control processes and their temporal dynamics. Biological Psychology, 123, 250-268.
Elchlepp H, Best M, Lavric A, Monsell S (2017). Shifting Attention Between Visual Dimensions as a Source of Switch Costs.
Psychological Science,
28(4), 470-481.
Abstract:
Shifting Attention Between Visual Dimensions as a Source of Switch Costs
Task-switching experiments have documented a puzzling phenomenon: Advance warning of the switch reduces but does not eliminate the switch cost. Theoretical accounts have posited that the residual switch cost arises when one selects the relevant stimulus–response mapping, leaving earlier perceptual processes unaffected. We put this assumption to the test by seeking electrophysiological markers of encoding a perceptual dimension. Participants categorized a colored letter as a vowel or consonant or its color as “warm” or “cold.” Orthogonally to the color manipulation, some colors were eight times more frequent than others, and the letters were in upper- or lowercase. Color frequency modulated the electroencephalogram amplitude at around 150 ms when participants repeated the color-classification task. When participants switched from the letter task to the color task, this effect was significantly delayed. Thus, even when prepared for, a task switch delays or prolongs encoding of the relevant perceptual dimension.
Abstract.
Elchlepp H, Lavric A, Chambers CD, Verbruggen F (2016). Proactive inhibitory control: a general biasing account. Cognitive Psychology, 86, 27-61.
Elchlepp H, Lavric A, Monsell S (2015). A change of task prolongs early processes: evidence from ERPs in lexical tasks.
J Exp Psychol Gen,
144(2), 299-325.
Abstract:
A change of task prolongs early processes: evidence from ERPs in lexical tasks.
Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.
Abstract.
Author URL.
Elchlepp H, Rumball F, Lavric A (2013). A brain-potential correlate of task-set conflict.
Psychophysiology,
50(3), 314-323.
Abstract:
A brain-potential correlate of task-set conflict
Brain potential correlates of response conflict are well documented, but those of task conflict are not. Task-switching studies have suggested a plausible correlate of task conflict – a post-stimulus posterior negativity – however, in such paradigms the negativity may also reflect post-stimulus task-set reconfiguration postulated in some models. Here participants alternated between single-task blocks of classifying letters and digits; hence no within-block task-set reconfiguration was required. Presenting letters alongside digits slowed responses to the digits and elicited an ERP negativity from ~350 ms, relative to task-neutral symbols presented alongside digits, consistent with task conflict. The negativity was also present for congruent digit-letter stimuli; this and the lack of behavioral response congruency effects indicates conflict at the level of task-set rather than response selection.
Abstract.
Elchlepp H, Lavric A, Mizon G, Monsell S (2012). A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Human Brain Mapping,
33, 1137-1154.
Abstract:
A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Behavioural and neurophysiological studies of task-switching have tended to employ ‘bivalent’ stimuli (which afford responses in two tasks). Using brain potential recordings, we investigated task-switching with ‘univalent’ stimuli affording responses in only one of the tasks, and compared the outcomes to those recently obtained with bivalent stimuli (Lavric et al. [2008]: Eur J
Neurosci 1-14), in order to examine two phenomena. First, when only univalent stimuli are presented, the processing of task cues becomes optional. Our results showed that in these circumstances linguistic (but not pictorial) cues were still effective in eliciting at least some degree of preparation for a taskswitch, as evidenced by the reduction in the error cost of switching at the longer preparation interval
and by a posterior switch-induced ERP positivity at about 450–800 ms in the cue-stimulus interval.
Second, single affordance stimuli not only reduced behavioural switch costs relative to bivalent stimuli; they also produced a smaller post-stimulus switch-induced negativity, consistent with the latter being a marker of conflict between task-sets. However, using stimuli not associated with responses in the
alternative task did not completely eliminate the negativity. We speculate that the residue reflects other sources of conflict: attention to the irrelevant perceptual dimension and/or persistence of task goals.
Abstract.
Publications by category
Journal articles
Elchlepp H, Monsell S, Lavric A (In Press). How Task Set and Task Switching Modulate Perceptual Processes: is Recognition of Facial Emotion an Exception?. Journal of Cognition
Rastle K, Lavric A, Elchlepp H, Crepaldi D (In Press). Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Journal of Experimental Psychology Human Perception & PerformanceAbstract:
Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test two key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems; and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and while priming for regular and irregular inflections was observed in a time window reflecting processing 400-600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterisation of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approaches.
Abstract.
Longman CS, Elchlepp H, Monsell S, Lavric A (2021). Serial or parallel proactive control of components of task-set? a task-switching investigation with concurrent EEG and eye-tracking.
Neuropsychologia,
160Abstract:
Serial or parallel proactive control of components of task-set? a task-switching investigation with concurrent EEG and eye-tracking.
Among the issues examined by studies of cognitive control in multitasking is whether processes underlying performance in the different tasks occur serially or in parallel. Here we ask a similar question about processes that pro-actively control task-set. In task-switching experiments, several indices of task-set preparation have been extensively documented, including anticipatory orientation of gaze to the task-relevant location (an unambiguous marker of reorientation of attention), and a positive polarity brain potential over the posterior cortex (whose functional significance is less well understood). We examine whether these markers of preparation occur in parallel or serially, and in what order. On each trial a cue required participants to make a semantic classification of one of three digits presented simultaneously, with the location of each digit consistently associated with one of three classification tasks (e.g. if the task was odd/even, the digit at the top of the display was relevant). The EEG positivity emerged following, and appeared time-locked to, the anticipatory fixation on the task-relevant location, which might suggest serial organisation. However, the fixation-locked positivity was not better defined than the cue-locked positivity; in fact, for the trials with the earliest fixations the positivity was better time-locked to the cue onset. This is more consistent with (re)orientation of spatial attention occurring in parallel with, but slightly before, the reconfiguration of other task-set components indexed by the EEG positivity.
Abstract.
Author URL.
Civile C, Cooke A, Liu X, McLaren R, Elchlepp H, Lavric A, Milton F, McLaren I (2020). The effect of tDCS on recognition depends on stimulus generalization: Neuro-stimulation can predictably enhance or reduce the face inversion effect. Journal of Experimental Psychology: Animal Learning and Cognition, 46, 83-98.
Lavric A, Clapp A, East A, Elchlepp H, Monsell S (2018). Is preparing for a language switch like preparing for a task switch? (Article). Journal of Experimental Psychology: Learning, Memory, and Cognition
Civile C, Elchlepp H, McLaren RP, Galang CM, Lavric A, McLaren IPL (2018). The effect of scrambling upright and inverted faces on the N170. Quarterly Journal of Experimental Psychology
Elchlepp H, Verbruggen F (2017). How to withhold or replace a prepotent response: an analysis of the underlying control processes and their temporal dynamics. Biological Psychology, 123, 250-268.
Elchlepp H, Best M, Lavric A, Monsell S (2017). Shifting Attention Between Visual Dimensions as a Source of Switch Costs.
Psychological Science,
28(4), 470-481.
Abstract:
Shifting Attention Between Visual Dimensions as a Source of Switch Costs
Task-switching experiments have documented a puzzling phenomenon: Advance warning of the switch reduces but does not eliminate the switch cost. Theoretical accounts have posited that the residual switch cost arises when one selects the relevant stimulus–response mapping, leaving earlier perceptual processes unaffected. We put this assumption to the test by seeking electrophysiological markers of encoding a perceptual dimension. Participants categorized a colored letter as a vowel or consonant or its color as “warm” or “cold.” Orthogonally to the color manipulation, some colors were eight times more frequent than others, and the letters were in upper- or lowercase. Color frequency modulated the electroencephalogram amplitude at around 150 ms when participants repeated the color-classification task. When participants switched from the letter task to the color task, this effect was significantly delayed. Thus, even when prepared for, a task switch delays or prolongs encoding of the relevant perceptual dimension.
Abstract.
Elchlepp H, Lavric A, Chambers CD, Verbruggen F (2016). Proactive inhibitory control: a general biasing account. Cognitive Psychology, 86, 27-61.
Elchlepp H, Lavric A, Monsell S (2015). A change of task prolongs early processes: evidence from ERPs in lexical tasks.
J Exp Psychol Gen,
144(2), 299-325.
Abstract:
A change of task prolongs early processes: evidence from ERPs in lexical tasks.
Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.
Abstract.
Author URL.
Rastle K, Lavric A, Elchlepp H, Crepaldi D (2015). Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Journal of Experimental Psychology: Human Perception and PerformanceAbstract:
Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs
© 2015 APA, all rights reserved). Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test 2 key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and although priming for regular and irregular inflections was observed in a time window reflecting processing 400 to 600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterization of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approaches. (PsycINFO Database Record
Abstract.
Leiva A, Parmentier FBR, Elchlepp H, Verbruggen F (2015). Reorienting the mind: the impact of novel sounds on go/no-go performance. Journal of Experimental Psychology: Human Perception and Performance, 41(5), 1197-1202.
Civile C, Zhao D, Ku Y, Elchlepp H, Lavric A, McLaren IPL (2014). Perceptual learning and inversion effects: Recognition of prototype-defined familiar checkerboards.
J Exp Psychol Anim Learn Cogn,
40(2), 144-161.
Abstract:
Perceptual learning and inversion effects: Recognition of prototype-defined familiar checkerboards.
The face inversion effect is a defection in performance in recognizing inverted faces compared with faces presented in their usual upright orientation typically believed to be specific for facial stimuli. McLaren (1997) was able to demonstrate that (a) an inversion effect could be obtained with exemplars drawn from a familiar category, such that upright exemplars were better discriminated than inverted exemplars; and (b) that the inversion effect required that the familiar category be prototype-defined. In this article, we replicate and extend these findings. We show that the inversion effect can be obtained in a standard old/new recognition memory paradigm, demonstrate that it is contingent on familiarization with a prototype-defined category, and establish that the effect is made up of two components. We confirm the advantage for upright exemplars drawn from a familiar, prototype-defined category, and show that there is a disadvantage for inverted exemplars drawn from this category relative to suitable controls. We also provide evidence that there is an N170 event-related potential signature for this effect. These results allow us to integrate a theory of perceptual learning originally proposed by McLaren, Kaye, and Mackintosh (1989) with explanations of the face inversion effect, first reported by Yin.
Abstract.
Author URL.
Elchlepp H, Rumball F, Lavric A (2013). A brain-potential correlate of task-set conflict.
Psychophysiology,
50(3), 314-323.
Abstract:
A brain-potential correlate of task-set conflict
Brain potential correlates of response conflict are well documented, but those of task conflict are not. Task-switching studies have suggested a plausible correlate of task conflict – a post-stimulus posterior negativity – however, in such paradigms the negativity may also reflect post-stimulus task-set reconfiguration postulated in some models. Here participants alternated between single-task blocks of classifying letters and digits; hence no within-block task-set reconfiguration was required. Presenting letters alongside digits slowed responses to the digits and elicited an ERP negativity from ~350 ms, relative to task-neutral symbols presented alongside digits, consistent with task conflict. The negativity was also present for congruent digit-letter stimuli; this and the lack of behavioral response congruency effects indicates conflict at the level of task-set rather than response selection.
Abstract.
Elchlepp, H. Rumball, F. Lavric A (2013). A brain-potential correlate of task-set conflict. Psychophysiology, 50, 314-323.
Elchlepp H, Lavric A, Mizon G, Monsell S (2012). A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Human Brain Mapping,
33, 1137-1154.
Abstract:
A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Behavioural and neurophysiological studies of task-switching have tended to employ ‘bivalent’ stimuli (which afford responses in two tasks). Using brain potential recordings, we investigated task-switching with ‘univalent’ stimuli affording responses in only one of the tasks, and compared the outcomes to those recently obtained with bivalent stimuli (Lavric et al. [2008]: Eur J
Neurosci 1-14), in order to examine two phenomena. First, when only univalent stimuli are presented, the processing of task cues becomes optional. Our results showed that in these circumstances linguistic (but not pictorial) cues were still effective in eliciting at least some degree of preparation for a taskswitch, as evidenced by the reduction in the error cost of switching at the longer preparation interval
and by a posterior switch-induced ERP positivity at about 450–800 ms in the cue-stimulus interval.
Second, single affordance stimuli not only reduced behavioural switch costs relative to bivalent stimuli; they also produced a smaller post-stimulus switch-induced negativity, consistent with the latter being a marker of conflict between task-sets. However, using stimuli not associated with responses in the
alternative task did not completely eliminate the negativity. We speculate that the residue reflects other sources of conflict: attention to the irrelevant perceptual dimension and/or persistence of task goals.
Abstract.
Lavric A, Elchlepp H, Rastle K (2012). Tracking hierarchical processing in morphological decomposition with brain potentials.
J Exp Psychol Hum Percept Perform,
38(4), 811-816.
Abstract:
Tracking hierarchical processing in morphological decomposition with brain potentials.
One important debate in psycholinguistics concerns the nature of morphological decomposition processes in visual word recognition (e.g. darkness = {dark} + {-ness}). One theory claims that these processes arise during orthographic analysis and prior to accessing meaning (Rastle & Davis, 2008), and another argues that these processes arise through greater temporal overlap between the activation of orthographic and semantic information (Feldman, O'Connor, & Moscoso del Prado Martín, 2009). This issue has been the subject of intense debate in studies using masked priming but has yet to be resolved unequivocally. The present study takes another approach to resolving this controversy by examining brain potentials as participants made lexical decisions to unprimed morphological (darkness), pseudomorphological (corner), and nonmorphological (brothel) stimuli. Results revealed a difference from ∼190 ms between the nonmorphological condition and the other 2 conditions (which showed no differentiation), a likely correlate of morphological processing reliant exclusively on orthography. Only 60-70 ms later was there evidence of the activation of semantic information, when the pseudomorphological condition diverged from the other 2 conditions. These results provide unambiguous support for a hierarchical model of morphological processing whereby decomposition is based initially on orthographic analysis and is only later constrained by semantic information. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Abstract.
Author URL.
Conferences
Best M, Elchlepp H, Verbruggen F (2014). EARLY MODULATION OF EVENT-RELATED POTENTIALS IN ASSOCIATIVELY-MEDIATED RESPONSE INHIBITION.
Author URL.
Elchlepp H, Chambers CD, Lavric A, Verbruggen F (2014). EXECUTIVE CONTROL OF ACTIONS EXAMINED WITH BRAIN POTENTIALS.
Author URL.
Verbruggen F, Elchlepp H (2014). PROACTIVE AND REACTIVE STOPPING: AN ATTENTIONAL ACCOUNT.
Author URL.
Publications by year
In Press
Elchlepp H, Monsell S, Lavric A (In Press). How Task Set and Task Switching Modulate Perceptual Processes: is Recognition of Facial Emotion an Exception?. Journal of Cognition
Rastle K, Lavric A, Elchlepp H, Crepaldi D (In Press). Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Journal of Experimental Psychology Human Perception & PerformanceAbstract:
Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test two key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems; and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and while priming for regular and irregular inflections was observed in a time window reflecting processing 400-600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterisation of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approaches.
Abstract.
2021
Longman CS, Elchlepp H, Monsell S, Lavric A (2021). Serial or parallel proactive control of components of task-set? a task-switching investigation with concurrent EEG and eye-tracking.
Neuropsychologia,
160Abstract:
Serial or parallel proactive control of components of task-set? a task-switching investigation with concurrent EEG and eye-tracking.
Among the issues examined by studies of cognitive control in multitasking is whether processes underlying performance in the different tasks occur serially or in parallel. Here we ask a similar question about processes that pro-actively control task-set. In task-switching experiments, several indices of task-set preparation have been extensively documented, including anticipatory orientation of gaze to the task-relevant location (an unambiguous marker of reorientation of attention), and a positive polarity brain potential over the posterior cortex (whose functional significance is less well understood). We examine whether these markers of preparation occur in parallel or serially, and in what order. On each trial a cue required participants to make a semantic classification of one of three digits presented simultaneously, with the location of each digit consistently associated with one of three classification tasks (e.g. if the task was odd/even, the digit at the top of the display was relevant). The EEG positivity emerged following, and appeared time-locked to, the anticipatory fixation on the task-relevant location, which might suggest serial organisation. However, the fixation-locked positivity was not better defined than the cue-locked positivity; in fact, for the trials with the earliest fixations the positivity was better time-locked to the cue onset. This is more consistent with (re)orientation of spatial attention occurring in parallel with, but slightly before, the reconfiguration of other task-set components indexed by the EEG positivity.
Abstract.
Author URL.
2020
Civile C, Cooke A, Liu X, McLaren R, Elchlepp H, Lavric A, Milton F, McLaren I (2020). The effect of tDCS on recognition depends on stimulus generalization: Neuro-stimulation can predictably enhance or reduce the face inversion effect. Journal of Experimental Psychology: Animal Learning and Cognition, 46, 83-98.
2018
Lavric A, Clapp A, East A, Elchlepp H, Monsell S (2018). Is preparing for a language switch like preparing for a task switch? (Article). Journal of Experimental Psychology: Learning, Memory, and Cognition
Lavric A, Clapp A, East A, Elchlepp H, Monsell S (2018). Is preparing for a language switch like preparing for a task switch? (Dataset).
Civile C, Elchlepp H, McLaren RP, Galang CM, Lavric A, McLaren IPL (2018). The effect of scrambling upright and inverted faces on the N170. Quarterly Journal of Experimental Psychology
2017
Elchlepp H, Verbruggen F (2017). How to withhold or replace a prepotent response: an analysis of the underlying control processes and their temporal dynamics. Biological Psychology, 123, 250-268.
Elchlepp H, Best M, Lavric A, Monsell S (2017). Shifting Attention Between Visual Dimensions as a Source of Switch Costs.
Psychological Science,
28(4), 470-481.
Abstract:
Shifting Attention Between Visual Dimensions as a Source of Switch Costs
Task-switching experiments have documented a puzzling phenomenon: Advance warning of the switch reduces but does not eliminate the switch cost. Theoretical accounts have posited that the residual switch cost arises when one selects the relevant stimulus–response mapping, leaving earlier perceptual processes unaffected. We put this assumption to the test by seeking electrophysiological markers of encoding a perceptual dimension. Participants categorized a colored letter as a vowel or consonant or its color as “warm” or “cold.” Orthogonally to the color manipulation, some colors were eight times more frequent than others, and the letters were in upper- or lowercase. Color frequency modulated the electroencephalogram amplitude at around 150 ms when participants repeated the color-classification task. When participants switched from the letter task to the color task, this effect was significantly delayed. Thus, even when prepared for, a task switch delays or prolongs encoding of the relevant perceptual dimension.
Abstract.
2016
Elchlepp H, Lavric A, Chambers CD, Verbruggen F (2016). Proactive inhibitory control: a general biasing account. Cognitive Psychology, 86, 27-61.
2015
Elchlepp H, Lavric A, Monsell S (2015). A change of task prolongs early processes: evidence from ERPs in lexical tasks.
J Exp Psychol Gen,
144(2), 299-325.
Abstract:
A change of task prolongs early processes: evidence from ERPs in lexical tasks.
Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.
Abstract.
Author URL.
Rastle K, Lavric A, Elchlepp H, Crepaldi D (2015). Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs.
Journal of Experimental Psychology: Human Perception and PerformanceAbstract:
Processing Differences Across Regular and Irregular Inflections Revealed Through ERPs
© 2015 APA, all rights reserved). Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test 2 key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and although priming for regular and irregular inflections was observed in a time window reflecting processing 400 to 600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterization of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approaches. (PsycINFO Database Record
Abstract.
Leiva A, Parmentier FBR, Elchlepp H, Verbruggen F (2015). Reorienting the mind: the impact of novel sounds on go/no-go performance. Journal of Experimental Psychology: Human Perception and Performance, 41(5), 1197-1202.
2014
Best M, Elchlepp H, Verbruggen F (2014). EARLY MODULATION OF EVENT-RELATED POTENTIALS IN ASSOCIATIVELY-MEDIATED RESPONSE INHIBITION.
Author URL.
Elchlepp H, Chambers CD, Lavric A, Verbruggen F (2014). EXECUTIVE CONTROL OF ACTIONS EXAMINED WITH BRAIN POTENTIALS.
Author URL.
Verbruggen F, Elchlepp H (2014). PROACTIVE AND REACTIVE STOPPING: AN ATTENTIONAL ACCOUNT.
Author URL.
Civile C, Zhao D, Ku Y, Elchlepp H, Lavric A, McLaren IPL (2014). Perceptual learning and inversion effects: Recognition of prototype-defined familiar checkerboards.
J Exp Psychol Anim Learn Cogn,
40(2), 144-161.
Abstract:
Perceptual learning and inversion effects: Recognition of prototype-defined familiar checkerboards.
The face inversion effect is a defection in performance in recognizing inverted faces compared with faces presented in their usual upright orientation typically believed to be specific for facial stimuli. McLaren (1997) was able to demonstrate that (a) an inversion effect could be obtained with exemplars drawn from a familiar category, such that upright exemplars were better discriminated than inverted exemplars; and (b) that the inversion effect required that the familiar category be prototype-defined. In this article, we replicate and extend these findings. We show that the inversion effect can be obtained in a standard old/new recognition memory paradigm, demonstrate that it is contingent on familiarization with a prototype-defined category, and establish that the effect is made up of two components. We confirm the advantage for upright exemplars drawn from a familiar, prototype-defined category, and show that there is a disadvantage for inverted exemplars drawn from this category relative to suitable controls. We also provide evidence that there is an N170 event-related potential signature for this effect. These results allow us to integrate a theory of perceptual learning originally proposed by McLaren, Kaye, and Mackintosh (1989) with explanations of the face inversion effect, first reported by Yin.
Abstract.
Author URL.
2013
Elchlepp H, Rumball F, Lavric A (2013). A brain-potential correlate of task-set conflict.
Psychophysiology,
50(3), 314-323.
Abstract:
A brain-potential correlate of task-set conflict
Brain potential correlates of response conflict are well documented, but those of task conflict are not. Task-switching studies have suggested a plausible correlate of task conflict – a post-stimulus posterior negativity – however, in such paradigms the negativity may also reflect post-stimulus task-set reconfiguration postulated in some models. Here participants alternated between single-task blocks of classifying letters and digits; hence no within-block task-set reconfiguration was required. Presenting letters alongside digits slowed responses to the digits and elicited an ERP negativity from ~350 ms, relative to task-neutral symbols presented alongside digits, consistent with task conflict. The negativity was also present for congruent digit-letter stimuli; this and the lack of behavioral response congruency effects indicates conflict at the level of task-set rather than response selection.
Abstract.
Elchlepp, H. Rumball, F. Lavric A (2013). A brain-potential correlate of task-set conflict. Psychophysiology, 50, 314-323.
2012
Elchlepp H, Lavric A, Mizon G, Monsell S (2012). A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Human Brain Mapping,
33, 1137-1154.
Abstract:
A brain-potential study of preparation for and execution of a task-switch with stimuli that afford only the relevant task.
Behavioural and neurophysiological studies of task-switching have tended to employ ‘bivalent’ stimuli (which afford responses in two tasks). Using brain potential recordings, we investigated task-switching with ‘univalent’ stimuli affording responses in only one of the tasks, and compared the outcomes to those recently obtained with bivalent stimuli (Lavric et al. [2008]: Eur J
Neurosci 1-14), in order to examine two phenomena. First, when only univalent stimuli are presented, the processing of task cues becomes optional. Our results showed that in these circumstances linguistic (but not pictorial) cues were still effective in eliciting at least some degree of preparation for a taskswitch, as evidenced by the reduction in the error cost of switching at the longer preparation interval
and by a posterior switch-induced ERP positivity at about 450–800 ms in the cue-stimulus interval.
Second, single affordance stimuli not only reduced behavioural switch costs relative to bivalent stimuli; they also produced a smaller post-stimulus switch-induced negativity, consistent with the latter being a marker of conflict between task-sets. However, using stimuli not associated with responses in the
alternative task did not completely eliminate the negativity. We speculate that the residue reflects other sources of conflict: attention to the irrelevant perceptual dimension and/or persistence of task goals.
Abstract.
Lavric A, Elchlepp H, Rastle K (2012). Tracking hierarchical processing in morphological decomposition with brain potentials.
J Exp Psychol Hum Percept Perform,
38(4), 811-816.
Abstract:
Tracking hierarchical processing in morphological decomposition with brain potentials.
One important debate in psycholinguistics concerns the nature of morphological decomposition processes in visual word recognition (e.g. darkness = {dark} + {-ness}). One theory claims that these processes arise during orthographic analysis and prior to accessing meaning (Rastle & Davis, 2008), and another argues that these processes arise through greater temporal overlap between the activation of orthographic and semantic information (Feldman, O'Connor, & Moscoso del Prado Martín, 2009). This issue has been the subject of intense debate in studies using masked priming but has yet to be resolved unequivocally. The present study takes another approach to resolving this controversy by examining brain potentials as participants made lexical decisions to unprimed morphological (darkness), pseudomorphological (corner), and nonmorphological (brothel) stimuli. Results revealed a difference from ∼190 ms between the nonmorphological condition and the other 2 conditions (which showed no differentiation), a likely correlate of morphological processing reliant exclusively on orthography. Only 60-70 ms later was there evidence of the activation of semantic information, when the pseudomorphological condition diverged from the other 2 conditions. These results provide unambiguous support for a hierarchical model of morphological processing whereby decomposition is based initially on orthographic analysis and is only later constrained by semantic information. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Abstract.
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