The locus of tool-transformation costs

Transformations of hand movements by tools such as levers or electronic input devices can invoke performance costs compared to untransformed movements. This study investigated by means of the Psychological Refractory Period (PRP) paradigm at which stage of information processing such tool-transformation costs arise. We used an inversion transformation, that is, the movement of the operating hand was transformed into a spatially incompatible movement of a lever. As a basic tool-transformation effect, the initiation of inverted tool movements was delayed compared to noninverted movements. Experiment 1 suggested a central (or postcentral) locus of this tool-transformation effect and ruled out a (precentral) perceptual locus. Experiments 2 and 3 confirmed the central locus and ruled out a later, motor-related stage of processing. The results show that spatially incompatible tool movements delay a capacity-limited stage of information processing, often referred to as response selection.     

Common mechanisms in error monitoring and action effect monitoring

In the present study, we considered error-related brain activity in event-related potentials, to investigate the relationship between error monitoring—that is, the detection and evaluation of erroneous responses—and action effect monitoring—that is, monitoring of the sensory consequences of behavior. To this end, participants worked on a task-switching paradigm that consisted of a free-choice task, in which a puzzle piece had to be attached to an existing one (the prime task), and a subsequent color flanker task (the probe task). We examined whether unexpected action effects in the prime task would affect the subsequent error monitoring in the probe task. We found the neural correlates of error monitoring during the probe task, the error-related negativity as well as the error positivity, to be increased after unexpected action effects in the prime task. In contrast, the neural correlates of visual attention were decreased after unexpected action effects, in line with recent findings on an attenuation of sensory processing after errors. Our results demonstrate a direct link between monitoring processes in the two tasks. We propose that both error monitoring and action effect monitoring rely on a common generic monitoring system related to novelty detection or affective processing. Preactivating this system by means of unexpected action effects increases the sensitivity for detecting an error in the subsequent task.     

Do endogenous and exogenous action control compete for perception?

Human actions are guided either by endogenous action plans or by external stimuli in the environment. These two types of action control seem to be mediated by neurophysiologically and functionally distinct systems that interfere if an endogenously planned action suddenly has to be performed in response to an exogenous stimulus. In this case, the endogenous representation has to be deactivated first to give way to the exogenous system. Here we show that interference of endogenous and exogenous action control is not limited to motor-related aspects but also affects the perception of action-related stimuli. Participants associated two actions with contingent sensory effects in learning blocks. In subsequent test blocks, preparing one of these actions specifically impaired responding to the associated effect in an exogenous speeded detection task, yielding a blindness-like effect for arbitrary, learned action effects. In accordance with the theory of event coding, this finding suggests that action planning influences perception even in the absence of any physical similarities between action and to-be-perceived stimuli.     

Effects of a no-go Task 2 on Task 1 performance in dual - tasking: From benefits to costs

When two tasks are combined in a dual-task experiment, characteristics of Task 2 can influence Task 1 performance, a phenomenon termed the backward crosstalk effect (BCE). Besides instances depending on the (spatial) compatibility of both responses, a particularly interesting example was introduced by Miller (2006): If Task 2 was a no-go task (i.e., one not requiring any action at all), responses were slowed in Task 1. Subsequent work, however, also reported the opposite result—that is, faster Task 1 responses in cases of no-go Task 2 trials. We report three experiments aiming to more precisely identify the conditions under which a no-go Task 2 facilitates or impedes Task 1 performance. The results suggest that an adverse no-go BCE is only observed when the Task 2 response(s) are sufficiently prepared in advance, yielding strong inhibitory control demands for Task 2 that eventually hamper Task 1 processing as well (i.e., inhibitory costs). If this is not the case, encountering a no-go Task 2 trial facilitates Task 1 performance, suggesting that the underlying task representation is reduced to a single - task. These results are discussed in the context of other recent work on BCEs and of recently suggested accounts of the no-go BCE.     

The focus of attention in working memory: evidence from a word updating task

Three experiments examined the cognitive costs of item switching within working memory with a novel word updating task, thereby extending previous research to the field of linguistic stimuli and linguistic-graphemic updating operations. In Experiments 1 and 2 costs for switching between working memory items were evident on the word level, and they increased with an increasing word set size (Experiment 2). In contrast, a surprisingly similar switch effect on the level of letters was not affected by word set size (Experiment 2). Experiment 3 showed that this effect is not simply based on the need for re-orienting visual spatial attention. To account for the overall picture of results, a recursive model of attentional foci is proposed. Moreover, individual working memory span appears to be associated with the accuracy of item switching, but not with its speed.     

Monitoring and control in multitasking

Psychonomic Bulletin & Review - The idea that conflict detection triggers control adjustments has been considered a basic principle of cognitive control. So far, this “conflict-control...     

On the costs of refocusing items in working memory: a matter of inhibition or decay?

The present study investigates the mental processes that are applied to previously attended items of working memory. In an object-switching task, participants counted the number of sequentially presented objects. In Experiment 1 the processing time increased when the object category switched from the prior trial compared to a repetition. More importantly, the further in the past the last instance of a current category was presented, the more processing time was necessary - an observation suggesting passive decay rather than inhibition of previously attended items. However, results differed when only two object categories were employed. Experiment 2 suggests that the lack of a clear indication of decay with small numbers of categories was due to participants' expectancy of category switches rather than repetitions. Taken together, the results suggest that working memory items become less accessible the longer they have not been attended to, when strategic processes are controlled.     

Visual and tactile action effects determine bimanual coordination performance

Effect-based models of motor control assign a crucial role to anticipated perceptual feedback in action planning. Two experiments were conducted to test the validity of this proposal for discrete bimanual key press responses. The results revealed that the normally observed performance advantage for the preparation of two responses with homologous rather than non-homologous fingers becomes inverted when homologous fingers produce non-identical visual effects, and non-homologous fingers produce identical visual effects. In the second experiment the finger homology effect was strongly reduced when homologous fingers produced non-identical tactile feedback. The results show that representations of to-be-produced visual and tactile action effects both contribute to action planning, though possibly to a varying degree. Implications of these results for effect-based models of motor control are considered.