The fast and the slow of skilled bimanual rhythm production: parallel versus integrated timing

Professional pianists performed 2 bimanual rhythms at a wide range of different tempos. The polyrhythmic task required the combination of 2 isochronous sequences (3 against 4) between the hands; in the syncopated rhythm task successive keystrokes formed intervals of identical (isochronous) durations. At slower tempos, pianists relied on integrated timing control merging successive intervals between the hands into a common reference frame. A timer-motor model is proposed based on the concepts of rate fluctuation and the distinction between target specification and timekeeper execution processes as a quantitative account of performance at slow tempos. At rapid rates expert pianists used hand-independent, parallel timing control. In alternative to a model based on a single central clock, findings support a model of flexible control structures with multiple timekeepers that can work in parallel to accommodate specific task constraints.     

On the role of verbalization during task set selection: Switching or serial order control?

Recent task-switching work in which paper-and-pencil administered single-task lists were compared with task-alternation lists has demonstrated large increases in task-switch costs with concurrent articulatory suppression (AS), implicating a crucial role for verbalization during switching (Baddeley, Chincotta, & Adlam, 2001; Emerson & Miyake, 2003). Experiment 1 replicated this result, using computerized assessment, albeit with much smaller effect sizes than in the original reports. In Experiment 2, AS interference was reduced when a sequential cue (spatial location) that indicated the current position in the sequence of task alternations was given. Finally, in Experiment 3, switch trials and no-switch trials were compared within a block of alternating runs of two tasks. Again, AS interference was obtained mainly when the endogenous sequencing demand was high, and it was comparable for no-switch and switch trials. These results suggest that verbalization may be critical for endogenous maintenance and updating of a sequential plan, rather than exclusively for the actual switching process.     

Conflict, consciousness, and control

To what degree is executive conflict resolution dependent on conflict awareness? A recent study by Dehaene et al. compared neural responses to conflict elicited through either visible or subliminal primes. Despite behavioral conflict effects for both prime types, neural activity in a control network including the anterior cingulate cortex (ACC) was present only for visible primes. Along with other recent results, these findings have important implications for theories on the relationship between ACC, consciousness, and cognitive control.     

Motor-iconicity of sign language does not alter the neural systems underlying tool and action naming

Positron emission tomography was used to investigate whether the motor-iconic basis of certain forms in American Sign Language (ASL) partially alters the neural systems engaged during lexical retrieval. Most ASL nouns denoting tools and ASL verbs referring to tool-based actions are produced with a handshape representing the human hand holding a tool and with an iconic movement depicting canonical tool use, whereas the visual iconicity of animal signs is more idiosyncratic and inconsistent across signs. We investigated whether the motor-iconic relation between a sign and its referent alters the neural substrate for lexical retrieval in ASL. Ten deaf native ASL signers viewed photographs of tools/utensils or of actions performed with or without an implement and were asked to overtly produce the ASL sign for each object or action. The control task required subjects to judge the orientation of unknown faces. Compared to the control task, naming tools engaged left inferior and middle frontal gyri, bilateral parietal lobe, and posterior inferotemporal cortex. Naming actions performed with or without a tool engaged left inferior frontal gyrus, bilateral parietal lobe, and posterior middle temporal gyrus at the temporo-occipital junction (area MT). When motor-iconic verbs were compared with non-iconic verbs, no differences in neural activation were found. Overall, the results indicate that even when the form of a sign is indistinguishable from a pantomimic gesture, the neural systems underlying its production mirror those engaged when hearing speakers name tools or tool-based actions with speech.     

The cognitive and neural architecture of sequence representation

The authors theorize that 2 neurocognitive sequence-learning systems can be distinguished in serial reaction time experiments, one dorsal (parietal and supplementary motor cortex) and the other ventral (temporal and lateral prefrontal cortex). Dorsal system learning is implicit and associates noncategorized stimuli within dimensional modules. Ventral system learning can be implicit or explicit It also allows associating events across dimensions and therefore is the basis of cross-task integration or interference, depending on degree of cross-task correlation of signals. Accordingly, lack of correlation rather than limited capacity is responsible for dual-task effects on learning. The theory is relevant to issues of attentional effects on learning; the representational basis of complex, sequential skills; hippocampal-versus basal ganglia-based learning; procedural versus declarative memory; and implicit versus explicit memory.     

Differential effects of cue changes and task changes on task-set selection costs

A task-switching paradigm with a 2:1 mapping between cues and tasks was used to separate cue-switching processes (indexed through pure cue-switch costs) from actual task-switching processes (indexed through additional costs in case of cue and task changes). A large portion of total switch costs was due to cue changes (Experiments 1 and 2), and cue-switch costs but not task-switch costs were sensitive to effects of practice (Experiment 1) and preparation (Experiment 2). In contrast, task-switch costs were particularly sensitive to response-priming effects (Experiments 1 and 2) and task-set inhibition (Experiment 3). Results suggest two processing stages relevant during task-set selection: cue-driven retrieval of task rules from long-term memory and the automatic application of rules to a particular stimulus situation.     

Reliable and Valid Coding of Thin Slices of Video Footage: Applicability to the Assessment of Mother-Child Interactions

When using behavioral-observation methods for coding video footage, it is unknown how much time of an interaction needs to be coded to gain results that are representative for the behavior of interest. The current study examined this problem using the INTAKT, a standardized observational measure for assessing the quality of mother-child interactions. Results from coding only 10 min of each video (i.e., thin slices) were compared with results from coding the remaining parts (averaging about 40 min) of the interaction. Inter-rater agreement for the short versions taken from the beginning or the middle, but not the end of the interactions indicated satisfactory observer accuracy. Coding results did not differ between short and long video sequences, when sequences were taken from the middle of the interactions. Importantly, characteristic differences between different interactive situations were equally well represented in the short and long video sequences. Therefore, our results show that coding only 10 min of an interaction is as reliable and valid as coding full-length videos, if those short sequences are taken from the middle of an interaction. Our findings support the idea that for every method, it is necessary to individually determine the window duration that is long enough to gain results that are reliable and valid.     

Smiling and sad wrinkles: Age-related changes in the face and the perception of emotions and intentions

There is a common belief that wrinkles in the aging face reflect frequently experienced emotions and hence resemble these affective displays. This implies that the wrinkles and folds in elderly faces interfere with the perception of other emotions currently experienced by the elderly as well as with the inferences perceivers draw from these expressions. Whereas there is ample research on the impact of aging on emotion recognition, almost no research has focused on how emotions expressed by the elderly are perceived by others. The present research addresses this latter question. Young participants rated the emotion expressions and behavioral intentions of old and young faces displaying identical expressions. The findings suggest that emotions shown on older faces have reduced signal clarity and may consequently have less impact on inferences regarding behavioral intentions. Both effects can be expected to have negative consequences for rapport achieved in everyday interactions involving the elderly.     

Emotion in the neutral face: a mechanism for impression formation?

The current work examined contributions of emotion-resembling facial cues to impression formation. There exist common facial cues that make people look emotional, male or female, and from which we derive personality inferences. We first conducted a Pilot Study to assess these effects. We found that neutral female versus neutral male faces were rated as more submissive, affiliative, na?ve, honest, cooperative, babyish, fearful, happy, and less angry than neutral male faces. In our Primary Study, we then "warped" these same neutral faces over their corresponding anger and fear displays so the resultant facial appearance cues now structurally resembled emotion while retaining a neutral visage (e.g., no wrinkles, furrows, creases, etc.). The gender effects found in the Pilot Study were replicated in the Primary Study, suggesting clear stereotype-driven impressions. Critically, ratings of the neutral-over-fear warps versus neutral-over-anger warps also revealed a profile similar to the gender-based ratings, revealing perceptually driven impressions directly attributable to emotion overgeneralisation.