Dissociable effects of auditory attention switching and stimulus–response compatibility

Using a task-switching variant of dichotic listening, we examined the ability to intentionally switch auditory attention between two speakers. We specifically focused on possible interactions with stimulus–response compatibility. In each trial, two words, one spoken by a male and another by a female, were presented dichotically via headphones. In one experimental group, two animal names were presented, and the relevant animal had to be judged as smaller or larger than a sheep by pressing a left or right response key. In another group, two number words were presented and had to be judged as smaller or larger than 5. In each trial, a visual cue indicated the gender of the relevant speaker. Performance was worse when the gender of the relevant speaker switched from trial to trial. These switch costs were larger for animal names than for number words, suggesting stronger interference with slower access to semantic categories. Responses were slower if the side of the target stimulus (as defined by the relevant gender) was spatially incompatible with the required response (as defined by the size judgment). This stimulus–response compatibility effect did not differ across stimulus material and did not interact with attentional switch costs. These results indicate that auditory switch costs and stimulus–response compatibility effects are dissociable, referring to target selection and response selection, respectively.     

形而上学及其当代命运——A.F.科赫教授访谈

A.F.科赫教授因其对康德与德国观念论(尤其是黑格尔)的深入研究而著名,此外他非常熟悉分析哲学与实用主义的当代成果。这使他能够以一种不同于其前辈诠释者的方式来理解德国哲学,并以一种完全不同于布兰顿和麦克道威尔这两位当代著名的分析哲学家的方式对大西洋两岸的两种不同的哲学传统进行让人瞩目的融合。从科赫教授身上我们可以看到,一个在欧陆哲学传统中成长起来的哲学家如何吸收和消化分析哲学的成果并尝试建立起一种新的思想方式。     

The planning and execution of short auditory sequences

Action planning, but not action execution, in speeded tasks is typically faster when responses and their effects are compatible than when they are incompatible. We tested whether response-effect compatibility (REC) affects the execution of music-like sequential actions that require temporal regularity rather than rapidity. Musicians responded to metronomic visual stimuli by producing sequences of three taps at a specific tempo on three vertically aligned keys. Each tap triggered a tone. Key-to-tone mapping was either compatible or incompatible in terms of spatial height and pitch height. The results indicated that tap timing was more accurate with compatible than with incompatible mappings, both for taps produced before (Tap 1) and after (Taps 2 and 3) the onset of auditory feedback. Thus, the observed influence of REC on action execution was not due exclusively to actual auditory feedback. The anticipation of distal action effects may be involved in planning the dynamics of temporally precise movements.     

Correlates of tattoos and reference groups

520 college students from a public university in the southwest were questioned to examine correlations between having a tattoo and the presence of tattoos among their family and friends. Tattoos among both friends and family were positively correlated with respondents' having a tattoo. The magnitude of friends' influence was about double the influence of family.     

Task-set inertia and memory-consolidation bottleneck in dual tasks

Three dual-task experiments examined the influence of processing a briefly presented visual object for deferred verbal report on performance in an unrelated auditory-manual reaction time (RT) task. RT was increased at short stimulus-onset asynchronies (SOAs) relative to long SOAs, showing that memory consolidation processes can produce a functional processing bottleneck in dual-task performance. In addition, the experiments manipulated the spatial compatibility of the orientation of the visual object and the side of the speeded manual response. This cross-task compatibility produced relative RT benefits only when the instruction for the visual task emphasized overlap at the level of response codes across the task sets (Experiment 1). However, once the effective task set was in place, it continued to produce cross-task compatibility effects even in single-task situations (“ignore” trials in Experiment 2) and when instructions for the visual task did not explicitly require spatial coding of object orientation (Experiment 3). Taken together, the data suggest a considerable degree of task-set inertia in dual-task performance, which is also reinforced by finding costs of switching task sequences (e.g., AC → BC vs. BC → BC) in Experiment 3.     

Task switching and action sequencing

We investigated if task switching affects late response processes that occur after the selection of a response. Subjects performed a sequence of two responses. The first and second response were selected, and then executed in close succession. The interresponse interval (IRI) was taken as a measure of late response processes. The two responses could either belong to different tasks (task-switch condition), or to the same task that was performed twice (task-repetition condition). In all three experiments, the IRI was found to be longer in the task-switch condition than in the task-repetition condition, consistent with the idea that task switching affected late response processes. However, the effects of the manipulation of the stimulus-onset asynchrony revealed that the tendency to perform the two responses as a sequence was reduced in the task-switch condition relative to the task-repetition condition. Thus, the data do not provide unequivocal evidence for task switching affecting late response processes. The data show, however, that task switching affected action sequencing. Two actions that do not belong to the same task context are less likely to be performed as an action sequence. We suggest that task switching interacts with higher-order control processes that cannot be studied within the traditional task-switching paradigm.     

Chunking in task sequences modulates task inhibition

In a study of the formation of representations of task sequences and its influence on task inhibition, participants first performed tasks in a predictable sequence (e.g., ABACBC) and then performed the tasks in a random sequence. Half of the participants were explicitly instructed about the predictable sequence, whereas the other participants did not receive these instructions. Task-sequence learning was inferred from shorter reaction times (RTs) in predictable relative to random sequences. Persisting inhibition of competing tasks was indicated by increased RTs in n- 2 task repetitions (e.g., ABA) compared with n- 2 nonrepetitions (e.g., CBA). The results show task-sequence learning for both groups. However, task inhibition was reduced in predictable relative to random sequences among instructed-learning participants who formed an explicit representation of the task sequence, whereas sequence learning and task inhibition were independent in the noninstructed group. We hypothesize that the explicit instructions led to chunking of the task sequence, and that n- 2 repetitions served as chunk points (ABA-CBC), so that within-chunk facilitation modulated the inhibition effect.     

Crossmodal action selection: Evidence from dual-task compatibility

Response-related mechanisms of multitasking were studied by analyzing simultaneous processing of responses in different modalities (i.e., crossmodal action). Participants responded to a single auditory stimulus with a saccade, a manual response (single-task conditions), or both (dual-task condition). We used a spatially incompatible stimulus-response mapping for one task, but not for the other. Critically, inverting these mappings varied temporal task overlap in dual-task conditions while keeping spatial incompatibility across responses constant. Unlike previous paradigms, temporal task overlap was manipulated without utilizing sequential stimulus presentation, which might induce strategic serial processing. The results revealed dual-task costs, but these were not affected by an increase of temporal task overlap. This finding is evidence for parallel response selection in multitasking. We propose that crossmodal action is processed by a central mapping-selection mechanism in working memory and that the dual-task costs are mainly caused by mapping-related crosstalk.     

Lateralisation of diffuse positive and negative affect: Ascribing valence to ambiguous stimuli

The available evidence regarding the lateralisation of affect is rather divergent. Interestingly, the common procedure in previous research on affective lateralisation has been to measure hemispheric dominance following exposure to concrete affective stimuli. Therefore, prior research seems to tap primarily into the lateralisation of specific approach–avoidance motivations rather than diffuse affective states. The present research adopted an alternative methodological approach that excluded approach–avoidance motivations and merely studied the lateralised nature of diffuse affect. Participants evaluated ambiguous stimuli presented in either the right or left visual field. Results showed that stimuli presented in the left visual field were significantly more often ascribed a positive meaning compared to information in the right visual field. The present findings are compatible with related lateralised processes and underscore the necessity of distinguishing between specific motivations and diffuse affect.     

Why does natural scene categorization require little attention? Exploring attentional requirements for natural and synthetic stimuli

It was recently demonstrated that detecting target objects (e.g., animals) in natural scenes can be done in a dual-task paradigm, in the near absence of spatial attention. Under the same conditions, subjects were unable to perform apparently simpler tasks involving synthetic stimuli (e.g., discriminating randomly rotated Ts and Ls, or a bisected colour disc and its mirror image). Classical theories predict that attention is more critical for the recognition of complex stimuli that cannot be easily separated on a single feature dimension. Therefore, these puzzling results have raised a number of questions. If it is not the complexity of a stimulus, what then determines the recognition task's attentional requirements? How does this differ between natural and artificial stimuli? What can these observations tell us about the mechanism of natural scene processing as well as its relation to attention? Here we show that removing colour information, or doubling the amount of information to be analysed, failed to make the natural scene categorization tasks significantly more “attention demanding”. Conversely, increasing discriminability or predictability did not diminish the need for attention in the case of synthetic stimuli. However, when the familiar letters, such as Ts or Ls, were presented upright, full attention was no longer required for discrimination. This suggests that familiarity and meaningfulness might be among the factors that determine attentional requirements for both natural and synthetic stimuli.