Exploring "phasic" vs. "tonic" accounts of the effect of switch probability on the auditory attention switch cost.

Task-switching experiments have shown that the "switch cost" (poorer performance for task switches than for repetitions) is smaller when the probability of a switch is high (e.g., 0.75) than when it is low (e.g., 0.25). Some theoretical accounts explain this effect in terms of top-down control deployed in advance of the task cue ("pre-cue reconfiguration"). We tested such accounts by manipulating the time available before the onset of the cue (the response-cue interval, RCI), reasoning that top-down pre-cue reconfiguration requires time and therefore its effect should increase with RCI. Participants heard a man and a woman simultaneously speaking number words and categorised the number (< 5 vs. > 5) spoken by the voice specified by a pictorial gender-related cue presented at an RCI of 100 ms or 2,200 ms. The target voice switched with a probability of 0.25 or 0.75 (in separate sessions). In Experiment 1, RTs revealed a large effect of switch probability on the switch cost in the short RCI, which did not increase in the long RCI. Errors hinted at such an increase, but it did not receive clear statistical support and was disconfirmed by a direct and better powered replication in Experiment 2, which fully confirmed the RT pattern from Experiment 1. Thus, the effect of switch probability on the switch cost required little/no time following the response to emerge-it was already at full magnitude at a short RCI-challenging accounts that assume "phasic" deployment of top-down task-set control in advance of the cue.

Does preparation help to switch auditory attention between simultaneous voices: Effects of switch probability and prevalence of conflict.

Switching auditory attention to one of two (or more) simultaneous voices incurs a substantial performance overhead. Whether/when this voice 'switch cost' reduces when the listener has opportunity to prepare in silence is not clear-the findings on the effect of preparation on the switch cost range from (near) null to substantial. We sought to determine which factors are crucial for encouraging preparation and detecting its effect on the switch cost in a paradigm where participants categorized the number spoken by one of two simultaneous voices; the target voice, which changed unpredictably, was specified by a visual cue depicting the target's gender. First, we manipulated the probability of a voice switch. When 25% of trials were switches, increasing the preparation interval (50/800/1,400 ms) resulted in substantial (~50%) reduction in switch cost. No reduction was observed when 75% of trials were switches. Second, we examined the relative prevalence of low-conflict, 'congruent' trials (where the numbers spoken by the two voices were mapped onto the same response) and high-conflict, 'incongruent' trials (where the voices afforded different responses). 'Conflict prevalence' had a strong effect on selectivity-the incongruent-congruent difference ('congruence effect') was reduced in the 66%-incongruent condition relative to the 66%-congruent condition-but conflict prevalence did not discernibly interact with preparation and its effect on the switch cost. Thus, conditions where switches of target voice are relatively rare are especially conducive to preparation, possibly because attention is committed more strongly to (and/or disengaged less rapidly from) the perceptual features of target voice.

Can we prevent social identity switches? An experimental-computational investigation.

Previous studies suggested that social identity switches are rapid and highly effective, raising the question of whether people can intentionally control such switches. In two studies, we tested if participants could exert top-down control to prevent a social identity switch triggered by the experimental context. In Study 1, participants (N = 198) were given a writing task aimed at prompting a switch from their parent identity to their feminist identity. Before the prompt, half of the participants (the experimental group) were instructed to remain in their parent identity, avoiding an identity switch; the control group was not given such instructions. We found no significant difference between the groups in either self-reported salience or the implicit computational measure of salience based on participants' linguistic style, both measures suggesting a switch in both groups. Study 2 (N = 380) followed the same design but included a monetary incentive to prevent the switch in the experimental group. The groups differed significantly in their self-reported salience but not in the implicit measure, which suggests limited ability to avoid the switch even when participants report being able to do so. These results point to limited intentional control over exogenously triggered identity switches, with important practical implications.

How Task Set and Task Switching Modulate Perceptual Processes: Is Recognition of Facial Emotion an Exception?

In Part 1 we review task-switching and other studies showing that, even with time for preparation, participants' ability to shift attention to a relevant attribute or object before the stimulus onset is limited: there is a 'residual cost'. In particular, several brain potential markers of perceptual encoding are delayed on task-switch trials, compared to task-repeat trials that require attention to the same attribute as before. Such effects have been documented even for a process often considered 'automatic' - visual word recognition: ERP markers of word frequency and word/nonword status are (1) delayed when the word recognition task follows a judgement of a perceptual property compared to repeating the lexical task, and (2) strongly attenuated during the perceptual judgements. Thus, even lexical access seems influenced by the task/attentional set. In Part 2, we report in detail a demonstration of what seems to be a special case, where task-set and a task switch have no such effect on perceptual encoding. Participants saw an outline letter superimposed on a face expressing neutral or negative emotion, and were auditorily cued to categorise the letter as vowel/consonant, or the face as emotional/neutral. ERPs exhibited a robust emotional-neutral difference (Emotional Expression Effect) no smaller or later when switching to the face task than when repeating it; in the first half of its time-course it did not vary with the task at all. The initial encoding of the valence of a fixated facial emotional expression appears to be involuntary and invariant, whatever the endogenous task/attentional set.

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.

Preparing to switch languages versus preparing to switch tasks: Which is more effective?

A substantial literature relates task-set control and language selection in bilinguals-with "switching" paradigms serving as a methodological "bridge." We asked a basic question: Is preparation for a switch equally effective in the two domains? Bilinguals switched between naming pictures in one language and another, or between the tasks of naming and categorizing pictures. The critical trials used for comparing the two kinds of switching were identical in all respects-task (naming), stimuli, responses-except one: whether the shape cue presented before the picture specified the language or the task. The effect of preparation on the "switch cost" was examined by varying the cue-stimulus interval (CSI; 50/800/1,175 ms). Preparation for a task switch was more effective: Increasing the CSI from 50 to 800 ms reduced the reaction time task switch cost by ∼63% to its minimum, but the language switch cost only by ∼24%, the latter continuing to reduce with further opportunity for preparation (CSI = 1,175 ms). The switch costs in the two domains correlated moderately (r = .36). We propose that preparation for a language switch is less effective, because (a) it must preemptively counteract greater interference during a language switch than during a task switch, and/or (b) lexical access is less amenable to "top-down" control than (components of) task-set. We also investigated the associations between stimuli and the language (or task) where they were last encountered. Associative history influenced performance-but similarly for switches and repetitions-indicating that stimulus-induced associative retrieval of language (or task-set) did not contribute to switch costs. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Has "Erasing" Made Things Clearer? Commentary on Schmidt, Liefooghe & De Houwer (): "An Episodic Model of Task Switching Effects: Erasing the Homunculus from Memory".

Commentary on Schmidt, Liefooghe & De Houwer (2020, JoC): "An episodic model of task switching effects: Erasing the homunculus from memory".

Testing the effects of transcranial direct current stimulation (tDCS) on the face inversion effect and the N170 event-related potentials (ERPs) component.

The following study investigates the effects of tDCS on face recognition skills indexed by the face inversion effect (better recognition performance for upright vs. inverted faces). We combined tDCS and EEG simultaneously to examine the effects of tDCS on the face inversion effect behaviourally and on the N170 ERPs component. The results from two experiments (overall N = 112) show that anodal tDCS delivered at Fp3 site for 10 min at 1.5 mA (double-blind and between-subjects) can reduce behaviourally the face inversion effect compared to sham (control) stimulation. The ERP results provide some evidence for tDCS being able to influence the face inversion effect on the N170. Specifically, we find a dissociation of the tDCS-induced effects where for the N170 latencies the tDCS reduces the usual face inversion effect (delayed N170 in response to inverted vs. upright faces) compared to sham. Contrarily, the same tDCS procedure on the same participants increased the inversion effect seen in the N170 amplitudes by making the negative deflection for the inverted faces that much greater than that for upright faces. We interpret our results in the context of the literature on the face inversion effect and the N170 peak component. In doing so, we extend our results to previous studies investigating the effects of tDCS on perceptual learning and face recognition.

The effect of tDCS on recognition depends on stimulus generalization: Neuro-stimulation can predictably enhance or reduce the face inversion effect.

This article reports results from three experiments that investigate how a particular neuro-stimulation procedure is able, in certain circumstances, to selectively increase the face inversion effect by enhancing recognition for upright faces, and argues that these effects can be understood in terms of the McLaren-Kaye-Mackintosh (MKM) theory of stimulus representation. We demonstrate how a specific transcranial direct current stimulation (tDCS) methodology can improve performance in circumstances where error-based salience modulation is making face recognition harder. The 3 experiments used an old/new recognition task involving sets of normal versus Thatcherized faces. The main characteristic of Thatcherized faces is that the eyes and the mouth are upside down, thus emphasizing features that tend to be common to other Thatcherized faces and so leading to stronger generalization making recognition worse. Experiment 1 combined a behavioral and event-related potential study looking at the N170 peak component, which helped us to calibrate the set of face stimuli needed for subsequent experiments. In Experiment 2, we used our tDCS procedure (between-subjects and double-blind) in an attempt to reduce the negative effects induced by error-based modulation of salience on recognition of upright Thatcherized faces. Results largely confirmed our predictions. In addition, they showed a significant improvement on recognition performance for upright normal faces. Experiment 3 provides the first direct evidence in a single study that the same tDCS procedure is able to both enhance performance when normal faces are presented with Thatcherized faces, and to reduce performance when normal faces are presented with other normal faces (i.e., male vs. female faces). We interpret our results by analyzing how salience modulation influences generalization between similar categories of stimuli. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Can we prepare to attend to one of two simultaneous voices?

We can selectively attend to one of two simultaneous voices sharing a source location. Can we endogenously select the voice before speech is heard? Participants heard two digit names, spoken simultaneously by a male voice and a female voice, following a visual cue indicating which voice's digit to classify as odd or even. There was a substantial cost in reaction time and errors when the target voice switched from one trial to the next. In Experiment 1, with a highly familiar pair of voices, the switch cost reduced by nearly half as the cue-stimulus interval increased from 50 to 800 ms, indicating (contrary to previous reports) effective endogenous preparation for a change of voice. No further reduction in switch cost occurred with a longer preparation interval-this "residual" switch cost may be attributable to attentional "inertia." In Experiment 2, with previously unfamiliar voices, the pattern of switch costs was very similar, though repeated attention to the same target voice over a run of trials improved performance more. Delaying the onset of one voice by 366 ms improved performance, but the pattern of preparatory tuning effects was similar. Thus, endogenous preparation for a voice is possible, but it is limited in efficacy, as for some other attentional domains. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Is preparing for a language switch like preparing for a task switch?

A key index of top-down control in task switching-preparation for a switch-is underexplored in language switching. The well-documented EEG "signature" of preparation for a task switch-a protracted positive-polarity modulation over the posterior scalp-has thus far not been reported in language switching, and the interpretation of previously reported effects of preparation on language switching performance is complicated by confounding factors. In an experiment using event-related potentials (ERPs) and an optimized picture-naming paradigm that addressed these confounds the language was specified by an auditory cue on every trial and changed unpredictably. There were two key manipulations. First, the cue-stimulus interval allowed either generous (1,500 ms) or little (100 ms) opportunity for preparation. Second, to explore the interplay between bottom-up and top-down language selection, we compared a highly transparent and familiar "supercue"-the name of the language spoken in that language to a relatively opaque cue (short speeded-up fragment of national anthem). Preparation for a switch elicited a brain potential strongly reminiscent of the posterior switch positivity documented in task switching. As previously shown in task switching, its amplitude inversely predicted the performance "switch cost," demonstrated by our ERP analyses contingent on reaction time (RT). This overlap in the electrophysiological correlates of preparing to switch tasks and languages suggests domain-general processes for top-down selection of task-set and language for production. But, the surprisingly small language switch cost following the supercue in the short CSI suggests that rapid and (possibly automatic) bottom-up selection-not typically observed in task switching-may also occur. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The effect of scrambling upright and inverted faces on the N170.

The face inversion effect refers to a decrement in performance when we try to recognise familiar faces turned upside down (inverted), compared with familiar faces presented in their usual (upright) orientation. Recently, we have demonstrated that the inversion effect can also be found with checkerboards drawn from prototype-defined categories when the participants have been trained with these categories, suggesting that factors such as expertise and the relationships between stimulus features may be important determinants of this effect. We also demonstrated that the typical inversion effect on the N170 seen with faces is found with checkerboards, suggesting that modulation of the N170 is a marker for disruption in the use of configural information. In the present experiment, we first demonstrate that our scrambling technique greatly reduces the inversion effect in faces. Following this, we used Event-Related Potentials ( ERPs) recorded while participants performed an Old/New recognition study on normal and scrambled faces presented in both upright and inverted orientations to investigate the impact of scrambling on the N170. We obtained the standard robust inversion effect for normal faces: The N170 was both larger and delayed for normal inverted faces as compared with normal upright faces, whereas a significantly reduced inversion effect was recorded for scrambled faces. These results show that the inversion effect on the N170 is greater for normal compared with scrambled faces, and we interpret the smaller effect for scrambled faces as being due to the reduction in expertise for those faces consequent on scrambling.

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.

Self-paced preparation for a task switch eliminates attentional inertia but not the performance switch cost.

The performance overhead associated with changing tasks (the "switch cost") usually diminishes when the task is specified in advance but is rarely eliminated by preparation. A popular account of the "residual" (asymptotic) switch cost is that it reflects "task-set inertia": carry-over of task-set parameters from the preceding trial(s). New evidence for a component of "task-set inertia" comes from eye-tracking, where the location associated with the previously (but no longer) relevant task is fixated preferentially over other irrelevant locations, even when preparation intervals are generous. Might such limits in overcoming task-set inertia in general, and "attentional inertia" in particular, result from suboptimal scheduling of preparation when the time available is outside one's control? In the present study, the stimulus comprised 3 digits located at the points of an invisible triangle, preceded by a central verbal cue specifying which of 3 classification tasks to perform, each consistently applied to just 1 digit location. The digits were presented only when fixation moved away from the cue, thus giving the participant control over preparation time. In contrast to our previous research with experimenter-determined preparation intervals, we found no sign of attentional inertia for the long preparation intervals. Self-paced preparation reduced but did not eliminate the performance switch cost-leaving a clear residual component in both reaction time and error rates. That the scheduling of preparation accounts for some, but not all, components of the residual switch cost, challenges existing accounts of the switch cost, even those which distinguish between preparatory and poststimulus reconfiguration processes. (PsycINFO Database Record

The coupling between spatial attention and other components of task-set: A task-switching investigation.

Is spatial attention reconfigured independently of, or in tandem with, other task-set components when the task changes? We tracked the eyes of participants cued to perform one of three digit-classification tasks, each consistently associated with a distinct location. Previously we observed, on task switch trials, a substantial delay in orientation to the task-relevant location and tendency to fixate the location of the previously relevant task-"attentional inertia". In the present experiments the cues specified (and instructions emphasized) the relevant location rather than the current task. In Experiment 1, with explicit spatial cues (arrows or spatial adverbs), the previously documented attentional handicaps all but disappeared, whilst the performance "switch cost" increased. Hence, attention can become decoupled from other aspects of task-set, but at a cost to the efficacy of task-set preparation. Experiment 2 used arbitrary single-letter cues with instructions and a training regime that encouraged participants to interpret the cue as indicating the relevant location rather than task. As in our previous experiments, and unlike in Experiment 1, we now observed clear switch-induced attentional delay and inertia, suggesting that the natural tendency is for spatial attention and task-set to be coupled and that only quasi-exogenous location cues decouple their reconfiguration.

Proactive inhibitory control: A general biasing account.

Flexible behavior requires a control system that can inhibit actions in response to changes in the environment. Recent studies suggest that people proactively adjust response parameters in anticipation of a stop signal. In three experiments, we tested the hypothesis that proactive inhibitory control involves adjusting both attentional and response settings, and we explored the relationship with other forms of proactive and anticipatory control. Subjects responded to the color of a stimulus. On some trials, an extra signal occurred. The response to this signal depended on the task context subjects were in: in the 'ignore' context, they ignored it; in the 'stop' context, they had to withhold their response; and in the 'double-response' context, they had to execute a secondary response. An analysis of event-related brain potentials for no-signal trials in the stop context revealed that proactive inhibitory control works by biasing the settings of lower-level systems that are involved in stimulus detection, action selection, and action execution. Furthermore, subjects made similar adjustments in the double-response and stop-signal contexts, indicating an overlap between various forms of proactive action control. The results of Experiment 1 also suggest an overlap between proactive inhibitory control and preparatory control in task-switching studies: both require reconfiguration of task-set parameters to bias or alter subordinate processes. We conclude that much of the top-down control in response inhibition tasks takes place before the inhibition signal is presented.

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 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.

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.

How does response inhibition influence decision making when gambling?

Recent research suggests that response inhibition training can alter impulsive and compulsive behavior. When stop signals are introduced in a gambling task, people not only become more cautious when executing their choice responses, they also prefer lower bets when gambling. Here, we examined how stopping motor responses influences gambling. Experiment 1 showed that the reduced betting in stop-signal blocks was not caused by changes in information sampling styles or changes in arousal. In Experiments 2a and 2b, people preferred lower bets when they occasionally had to stop their response in a secondary decision-making task but not when they were instructed to respond as accurately as possible. Experiment 3 showed that merely introducing trials on which subjects could not gamble did not influence gambling preferences. Experiment 4 demonstrated that the effect of stopping on gambling generalized to different populations. Further, 2 combined analyses suggested that the effect of stopping on gambling preferences was reliable but small. Finally, Experiment 5 showed that the effect of stopping on gambling generalized to a different task. On the basis of our findings and earlier research, we propose that the presence of stop signals influences gambling by reducing approach behavior and altering the motivational value of the gambling outcome.

Individual reactions to stress predict performance during a critical aviation incident.

BACKGROUND: Understanding the influence of stress on human performance is of theoretical and practical importance. An individual's reaction to stress predicts their subsequent performance; with a "challenge" response to stress leading to better performance than a "threat" response. However, this contention has not been tested in truly stressful environments with highly skilled individuals. Furthermore, the effect of challenge and threat responses on attentional control during visuomotor tasks is poorly understood. DESIGN: Thus, this study aimed to examine individual reactions to stress and their influence on attentional control, among a cohort of commercial pilots performing a stressful flight assessment. METHODS: Sixteen pilots performed an "engine failure on take-off" scenario, in a high-fidelity flight simulator. Reactions to stress were indexed via self-report; performance was assessed subjectively (flight instructor assessment) and objectively (simulator metrics); gaze behavior data were captured using a mobile eye tracker, and measures of attentional control were subsequently calculated (search rate, stimulus driven attention, and entropy). RESULTS: Hierarchical regression analyses revealed that a threat response was associated with poorer performance and disrupted attentional control. CONCLUSION: The findings add to previous research showing that individual reactions to stress influence performance and shed light on the processes through which stress influences performance.