Exploring temporal dissipation of attention settings in auditory task switching

Using a cued auditory task-switching variant of dichotic listening, we varied the response–cue interval (RCI) to examine temporal dissipation effects. On each trial, participants were presented with two different number words, one spoken by a female speaker and another by a male speaker (dichotic listening), that served as competing targets for a numerical judgment. The gender of the task-relevant speaker was indicated by a visual task cue prior to each trial. Experiment 1A used two different cues for each task (i.e., gender) and showed only small cue repetition benefits (same cue vs. alternate cue) but large auditory switch costs (alternate cue vs. task switch). A replication without immediate cue repetitions (Experiment 1B) showed very similar switch costs, suggesting that immediate cue repetitions play a negligible role for the size of auditory task switch costs. Moreover, switch costs were reduced when the (entirely task-irrelevant) location of the task-relevant speaker changed, relative to when it was unchanged, suggesting an episodic feature-binding component in our dichotic-listening task. Importantly, both experiments showed no effect of RCI on auditory switch costs. Because statistical power for this null effect was reasonably high across experiments (n?=?50), this finding suggests that auditory attention settings do not dissipate quickly over time.     

Switching in the cocktail party: exploring intentional control of auditory selective attention

Using a novel variant of dichotic selective listening, we examined the control of auditory selective attention. In our task, subjects had to respond selectively to one of two simultaneously presented auditory stimuli (number words), always spoken by a female and a male speaker, by performing a numerical size categorization. The gender of the task-relevant speaker could change, as indicated by a visual cue prior to auditory stimulus onset. Three experiments show clear performance costs with instructed attention switches. Experiment 2 varied the cuing interval to examine advance preparation for an attention switch. Experiment 3 additionally isolated auditory switch costs from visual cue priming by using two cues for each gender, so that gender repetition could be indicated by a changed cue. Experiment 2 showed that switch costs decreased with prolonged cuing intervals, but Experiment 3 revealed that preparation did not affect auditory switch costs but only visual cue priming. Moreover, incongruent numerical categories in competing auditory stimuli produced interference and substantially increased error rates, suggesting continued processing of task-relevant information that often leads to responding to the incorrect auditory source. Together, the data show clear limitations in advance preparation of auditory attention switches and suggest a considerable degree of inertia in intentional control of auditory selection criteria.     

Task switching: effects of practice on switch and mixing costs

In the task-switching paradigm, mixing costs indicate the performance costs to mix two different tasks, while switch costs indicate the performance costs to switch between two sequentially presented tasks. Applying tasks with bivalent stimuli and responses, many studies demonstrated substantial mixing and switch costs and a reduction of these costs as a result of practice. The present study investigates whether extensive practice of a task-switching situation including tasks with univalent stimuli eliminates these costs. Participants practiced switching between a visual and an auditory task. These tasks were chosen because they had shown eliminated performance costs in a comparable dual-task practice study (Schumacher et al. Psychol Sci 12:101–108, 2001). Participants either performed the tasks with univalent responses (i.e., visual-manual and auditory-verbal stimulus–response mappings) or bivalent responses (i.e., visual-manual and auditory-manual stimulus–response mappings). Both valence conditions revealed substantial mixing and switch costs at the beginning of practice, yet, mixing costs were largely eliminated after eight practice sessions while switch costs were still existent.     

The role of crossmodal competition and dimensional overlap in crossmodal attention switching

Crossmodal selective attention was investigated in a cued task switching paradigm using bimodal visual and auditory stimulation. A cue indicated the imperative modality. Three levels of spatial S–R associations were established following perceptual (location), structural (numerical), and conceptual (verbal) set-level compatibility. In Experiment 1, participants switched attention between the auditory and visual modality either with a spatial-location or spatial-numerical stimulus set. In the spatial-location set, participants performed a localization judgment on left vs. right presented stimuli, whereas the spatial-numerical set required a magnitude judgment about a visually or auditorily presented number word. Single-modality blocks with unimodal stimuli were included as a control condition. In Experiment 2, the spatial-numerical stimulus set was replaced by a spatial-verbal stimulus set using direction words (e.g., “left”). RT data showed modality switch costs, which were asymmetric across modalities in the spatial-numerical and spatial-verbal stimulus set (i.e., larger for auditory than for visual stimuli), and congruency effects, which were asymmetric primarily in the spatial-location stimulus set (i.e., larger for auditory than for visual stimuli). This pattern of effects suggests task-dependent visual dominance.     

Inhibition of irrelevant category–response mappings

When switching tasks, performance tends to be worse for n – 2 repetitions than with n – 2 switches. This n – 2 repetition cost has been hypothesized to reflect task-set inhibition: specifically, inhibition of irrelevant category–response mappings involved in response selection. This hypothesis leads to divergent predictions for situations in which all tasks involve the same stimulus categories: An n – 2 repetition cost is predicted when response sets differ across tasks, but not when the response set stays the same. The authors tested these predictions by having subjects perform relative judgements with different reference points. In Experiment 1, the stimulus categories were the same across reference points, but the response set either differed or stayed the same (the multiple- and single-mapping conditions, respectively). An n – 2 repetition cost was found in the multiple-mapping condition but not in the single-mapping condition. Experiment 2 provided evidence against the possibility that these divergent effects reflected differences in memory load. These findings confirm predictions that link n – 2 repetition costs to inhibition of irrelevant category–response mappings.     

The road to understanding is paved with the speaker’s intentions: Cues to the speaker’s attention and intentions affect pronoun comprehension

A series of experiments explore the effects of attention-directing cues on pronoun resolution, contrasting four specific hypotheses about the interpretation of ambiguous pronouns he and she: (1) it is driven by grammatical rules, (2) it is primarily a function of social processing of the speaker’s intention to communicate, (3) it is modulated by the listener’s own egocentric attention, and (4) it is primarily a function of learned probabilistic cues. Experiment 1 demonstrates that pronoun interpretation is guided by the well-known N1 (first-mention) bias, which is also modulated by both the speaker’s gaze and pointing gestures. Experiment 2 demonstrates that a low-level visual capture cue has no effect on pronoun interpretation, in contrast with the social cue of pointing. Experiment 3 uses a novel intentional cue: the same attention-capture flash as in Experiment 2, but with instructions that the cue is intentionally created by the speaker. This cue does modulate the N1 bias, demonstrating the importance of information about the speaker’s intentions to pronoun resolution. Taken in sum, these findings demonstrate that pronoun resolution is a process best categorized as driven by an appreciation of the speaker’s communicative intent, which may be subserved by a sensitivity to predictive cues in the environment.     

Auditory attention switching and judgment switching: Exploring multicomponent task representations

An auditory attention-switching paradigm was combined with a judgment-switching paradigm to examine the interaction of a varying auditory attention component and a varying judgment component. Participants heard two dichotically presented stimuli—one spoken by a female speaker and one spoken by a male speaker. In each trial, the stimuli were a spoken letter and a spoken number. A visual explicit cue at the beginning of each trial indicated the auditory attention criterion (speaker sex/ear) to identify the target stimulus (Experiment 1) or the judgment that had to be executed (Experiment 2). Hence, the attentional selection criterion switched independently between speaker sexes (or between ears), while the judgment alternated between letter categorization and number categorization. The data indicate that auditory attention criterion and judgment were not processed independently, regardless of whether the attention criterion or the judgment was cued. The partial repetition benefits of the explicitly cued component suggested a hierarchical organization of the auditory attention component and the judgment component within the task set. We suggest that the hierarchy arises due to the explicit cuing of one component rather than due to a “natural” hierarchy of auditory attention component and judgment component.     

Modality-specific effects in bilingual language perception

ABSTRACT

Language switching typically leads to language switch costs. Previous studies demonstrated that production-based language switching often results in reduced costs when the languages are assigned to distinct modalities (i.e. bimodal language switching) compared to switching within a modality (i.e. unimodal switching). In Experiment 1–3, we compared unimodal to bimodal switching in language perception. In Experiment 4, unimodal switching was compared to bivocal switching (i.e. languages were assigned to different voices). Experiment 1–3 revealed significantly higher switch costs for bimodal than for unimodal switching, indicating fundamental differences to language production studies. While bimodal switching leads to no (additional) costs but – under specific conditions – even to advantage in production, it increases switch costs in language perception. Moreover, Experiment 4 indicates that this is more a modality-specific rather than a general perception-based effect. Different voices instead of different modalities evoked no similar increase in switch costs.     

Difficulties in auditory organization as a cause of reading backwardness? An auditory neuroscience perspective

Over 30 years ago, it was suggested that difficulties in the ‘auditory organization’ of word forms in the mental lexicon might cause reading difficulties. It was proposed that children used parameters such as rhyme and alliteration to organize word forms in the mental lexicon by acoustic similarity, and that such organization was impaired in developmental dyslexia. This literature was based on an ‘oddity’ measure of children's sensitivity to rhyme (e.g. wood, book, good) and alliteration (e.g. sun, sock, rag). The ‘oddity’ task revealed that children with dyslexia were significantly poorer at identifying the ‘odd word out’ than younger children without reading difficulties. Here we apply a novel modelling approach drawn from auditory neuroscience to study the possible sensory basis of the auditory organization of rhyming and non‐rhyming words by children. We utilize a novel Spectral‐Amplitude Modulation Phase Hierarchy (S‐AMPH) approach to analysing the spectro‐temporal structure of rhyming and non‐rhyming words, aiming to illuminate the potential acoustic cues used by children as a basis for phonological organization. The S‐AMPH model assumes that speech encoding depends on neuronal oscillatory entrainment to the amplitude modulation (AM) hierarchy in speech. Our results suggest that phonological similarity between rhyming words in the oddity task depends crucially on slow (delta band) modulations in the speech envelope. Contrary to linguistic assumptions, therefore, auditory organization by children may not depend on phonemic information for this task. Linguistically, it is assumed that ‘book’ does not rhyme with ‘wood’ and ‘good’ because the final phoneme differs. However, our auditory analysis suggests that the acoustic cues to this phonological dissimilarity depend primarily on the slower amplitude modulations in the speech envelope, thought to carry prosodic information. Therefore, the oddity task may help in detecting reading difficulties because phonological similarity judgements about rhyme reflect sensitivity to slow amplitude modulation patterns. Slower amplitude modulations are known to be detected less efficiently by children with dyslexia.     

The role of preparation and cue-modality in crossmodal task switching

The present study examined the effects of cue-based preparation and cue-target modality mapping in crossmodal task switching. In two experiments, we randomly presented lateralized visual and auditory stimuli simultaneously. Subjects were asked to make a left/right judgment for a stimulus in only one of the modalities. Prior to each trial, the relevant stimulus modality was indicated by a visual or auditory cue. The cueing interval was manipulated to examine preparation. In Experiment 1, we used a corresponding mapping of cue-modality and stimulus modality, whereas in Experiment 2 the mapping of cue and stimulus modalities was reversed. We found reduced modality-switch costs with a long cueing interval, showing that attention shifts to stimulus modalities can be prepared, irrespective of cue-target modality mapping. We conclude that perceptual processing in crossmodal switching can be biased in a preparatory way towards task-relevant stimulus modalities.     

Preschoolers trust novel members of accurate speakers' groups and judge them favourably

By age 3, children track a speaker's record of past accuracy and use it as a cue to current reliability. Two experiments (N?=?95 children) explored whether preschoolers' judgements about, and trust in, the accuracy of a previously reliable informant extend to other members of the informant's group. In Experiment 1, both 3- and 4-year-olds consistently judged an animated character who was associated with a previously accurate speaker more likely to be correct than a character associated with a previously inaccurate speaker, despite possessing no information about these characters' individual records of reliability. They continued to show this preference one week later. Experiment 2 presented 4- and 5-year-olds with a related task using videos of human actors. Both showed preferences for members of previously accurate speakers' groups on a common measure of epistemic trust. This result suggests that by at least age 4, children's trust in speaker testimony spreads to members of a previously accurate speaker's group.     

Learning words: children disregard some pragmatic information that conflicts with mutual exclusivity

Children tend to infer that when a speaker uses a new label, the label refers to an unlabeled object rather than one they already know the label for. Does this inference reflect a default assumption that words are mutually exclusive? Or does it instead reflect the result of a pragmatic reasoning process about what the speaker intended? In two studies, we distinguish between these possibilities. Preschoolers watched as a speaker pointed toward (Study 1) or looked at (Study 2) a familiar object while requesting the referent for a new word (e.g. ‘Can you give me the blicket?’). In both studies, despite the speaker's unambiguous behavioral cue indicating an intent to refer to a familiar object, children inferred that the novel label referred to an unfamiliar object. These results suggest that children expect words to be mutually exclusive even when a speaker provides some kinds of pragmatic evidence to the contrary.     

Intentional attention switching in dichotic listening: Exploring the efficiency of nonspatial and spatial selection

Using an auditory variant of task switching, we examined the ability to intentionally switch attention in a dichotic-listening task. In our study, participants responded selectively to one of two simultaneously presented auditory number words (spoken by a female and a male, one for each ear) by categorizing its numerical magnitude. The mapping of gender (female vs. male) and ear (left vs. right) was unpredictable. The to-be-attended feature for gender or ear, respectively, was indicated by a visual selection cue prior to auditory stimulus onset. In Experiment 1, explicitly cued switches of the relevant feature dimension (e.g., from gender to ear) and switches of the relevant feature within a dimension (e.g., from male to female) occurred in an unpredictable manner. We found large performance costs when the relevant feature switched, but switches of the relevant feature dimension incurred only small additional costs. The feature-switch costs were larger in ear-relevant than in gender-relevant trials. In Experiment 2, we replicated these findings using a simplified design (i.e., only within-dimension switches with blocked dimensions). In Experiment 3, we examined preparation effects by manipulating the cueing interval and found a preparation benefit only when ear was cued. Together, our data suggest that the large part of attentional switch costs arises from reconfiguration at the level of relevant auditory features (e.g., left vs. right) rather than feature dimensions (ear vs. gender). Additionally, our findings suggest that ear-based target selection benefits more from preparation time (i.e., time to direct attention to one ear) than gender-based target selection.     

Why does guessing incorrectly enhance,rather than impair,retention?

The finding that trying, and failing, to predict the upcoming to-be-remembered response to a given cue can enhance later recall of that response, relative to studying the intact cue–response pair, is surprising, especially given that the standard paradigm (e.g., Kornell, Hays, & Bjork, 2009) involves allocating what would otherwise be study time to generating an error. In three experiments, we sought to eliminate two potential heuristics that participants might use to aid recall of correct responses on the final test and to explore the effects of interference both at an immediate and at a delayed test. In Experiment 1, by intermixing strongly associated to-be-remembered pairs with weakly associated pairs, we eliminated a potential heuristic participants can use on the final test in the standard version of the paradigm—namely, that really strong associates are incorrect responses. In Experiment 2, by rigging half of the participants’ responses to be correct, we eliminated another potential heuristic—namely, that one’s initial guesses are virtually always wrong. In Experiment 3, we examined whether participants’ ability to remember—and discriminate between—their incorrect guesses and correct responses would be lost after a 48-h delay, when source memory should be reduced. Across all experiments, we continued to find a robust benefit of trying to guess to-be-learned responses, even when incorrect, versus studying intact cue–response pairs. The benefits of making incorrect guesses are not an artifact of the paradigm, nor are they limited to short retention intervals.     

Mixed signals: The effect of conflicting reward- and goal-driven biases on selective attention

Attentional selection depends on the interaction between exogenous (stimulus-driven), endogenous (goal-driven), and selection history (experience-driven) factors. While endogenous and exogenous biases have been widely investigated, less is known about their interplay with value-driven attention. The present study investigated the interaction between reward-history and goal-driven biases on perceptual sensitivity (d’) and response time (RT) in a modified cueing paradigm presenting two coloured cues, followed by sinusoidal gratings. Participants responded to the orientation of one of these gratings. In Experiment 1, one cue signalled reward availability but was otherwise task irrelevant. In Experiment 2, the same cue signalled reward, and indicated the target’s most likely location at the opposite side of the display. This design introduced a conflict between reward-driven biases attracting attention and goal-driven biases directing it away. Attentional effects were examined comparing trials in which cue and target appeared at the same versus opposite locations. Two interstimulus interval (ISI) levels were used to probe the time course of attentional effects. Experiment 1 showed performance benefits at the location of the reward-signalling cue and costs at the opposite for both ISIs, indicating value-driven capture. Experiment 2 showed performance benefits only for the long ISI when the target was at the opposite to the reward-associated cue. At the short ISI, only performance costs were observed. These results reveal the time course of these biases, indicating that reward-driven effects influence attention early but can be overcome later by goal-driven control. This suggests that reward-driven biases are integrated as attentional priorities, just as exogenous and endogenous factors.     

Identifying good opportunities to act: Implementation intentions and cue discrimination

Forming an implementation intention (‘If I encounter situation X, then I'll perform behaviour Y!’) is thought to increase the likelihood that the person will detect a good opportunity to act. Experiment 1 found support for this hypothesis in a novel context where detection of the specified cue was very difficult. Experiments 2 and 3 extended existing paradigms to test whether this improved cue detection has costs in terms of increased false positives and/or slower responses to ambiguous stimuli. This hypothesis was not supported. Forming an implementation intention led to more accurate (Experiment 2) and faster (Experiment 3) responses to the specified cue without compromising responses to non‐relevant, or ambiguous, stimuli. Overall, the findings suggest that forming an implementation intention is an effective self‐regulatory tool because the specified cues are discriminated swiftly and with precision. Copyright © 2004 John Wiley & Sons, Ltd.     

What makes responses prepotent for young children? Insights from the grass–snow task

Understanding how responses become prepotent is essential for understanding when inhibitory control is needed in everyday behaviour. We investigated prepotency in the grass–snow task—in which a child points to a green card when the experimenter says ‘snow’ and a white card when the experimenter says ‘grass’. Experiment 1 (n=48, mean age=3.5 years) investigated the response method effect—whether pointing is prepotent because it is habitual. Experiment 2 (n=60, mean age=3.5 years) investigated the response set effect—whether responses are prepotent because the child plans to make them in the task. Experiment 2 also provided evidence that children could remember the rules in the task. Experiment 3 (n=30, mean age=3.4 years) produced further evidence that children could remember these rules. We found no evidence for the response method and response set effects, suggesting that prepotency in the grass–snow task is more ‘stimulus‐driven’ than in tasks previously studied. The implications of our findings are discussed in relation to other developmental inhibitory tasks and to children's reliance on inhibitory control to regulate their everyday behaviour. Copyright © 2008 John Wiley & Sons, Ltd.     

Partial reinforcement and context switch effects in human predictive learning

Human participants were trained in a trial-by-trial contingency judgements task in which they had to predict the probability of an outcome (diarrhoea) following different cues (food names) in different contexts (restaurants). Cue P was paired with the outcome on half of the trials (partial reinforcement), while cue C was paired with the outcome on all the trials (continuous reinforcement), both cues in Context A. Test was conducted in both Context A and a different but equally familiar context (B). Context change decreased judgements to C, but not to P (Experiment 1). This effect was found only in the cue trained in the context where a different cue was partially reinforced (Experiment 2). Context switch effects disappeared when different cues received partial reinforcement in both contexts of training (Experiment 3). The implications of these results for an explanation of context switch effects in terms of ambiguity in the meaning of the cues prompting attention to the context (e.g., Bouton, 1997) are discussed.     

Partial reinforcement and context switch effects in human predictive learning

Human participants were trained in a trial-by-trial contingency judgements task in which they had to predict the probability of an outcome (diarrhoea) following different cues (food names) in different contexts (restaurants). Cue P was paired with the outcome on half of the trials (partial reinforcement), while cue C was paired with the outcome on all the trials (continuous reinforcement), both cues in Context A. Test was conducted in both Context A and a different but equally familiar context (B). Context change decreased judgements to C, but not to P (Experiment 1). This effect was found only in the cue trained in the context where a different cue was partially reinforced (Experiment 2). Context switch effects disappeared when different cues received partial reinforcement in both contexts of training (Experiment 3). The implications of these results for an explanation of context switch effects in terms of ambiguity in the meaning of the cues prompting attention to the context (e.g., Bouton, 1997) are discussed.     

Operant and Pavlovian factors in cross-response transfer of inhibitory stimulus control

Experiment 1 used a within-response procedure to compare inhibitory stimulus control of the extinction cue in multiple variable interval-extinction (mult VI EXT) and the variable time cue in multiple variable interval-variable time (mult VI VT). Experiment 2A made the same comparison using a crossresponse procedure. In addition, Experiment 2A also tested the extinction cue in multiple variable time-extinction (mult VT EXT), and Experiment 2B tested the variable time cue in mult VT EXT. Unlike the mult VI EXT and mult VI VT conditions, the mult VT EXT condition was administered in the absence of a response manipulandum. The main findings of the present study were: (1) cross-response suppression by the variable time cue in mult VI VT; (2) greater response suppression by the extinction cue in mult VI EXT than by either the variable time cue in mult VI VT or the extinction cue in mult VT EXT; and (3) response facilitation by the variable time cue in mult VT EXT. These findings indicate that inhibitory stimulus control based on an operant source (i.e., absence of an R-S contingency) does transfer across responses, and that such transfer cannot be explained in terms of competing responses. These findings also indicate that operant and Pavlovian sources of stimulus control summate algebraically to determine the inhibitory strength of the extinction cue in mult VI EXT. Finally, the third finding is not consistent with notions that emphasize the importance of location and localization of cues explicitly paired with positive events.