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Observing actions evokes an automatic imitative response that activates mechanisms required to execute these actions. Automatic imitation is measured using the Stimulus Response Compatibility (SRC) task, which presents participants with compatible and incompatible prompt-distractor pairs. Automatic imitation, or the compatibility effect, is the difference in response times (RTs) between incompatible and compatible trials. Past results suggest that an action's animacy affects automatic imitation: human-produced actions evoke larger effects than computer-generated actions. However, it appears that animacy effects occur mostly when non-human stimuli are less complex or less clear. Theoretical accounts make conflicting predictions regarding both stimulus manipulations. We conducted two SRC experiments that presented participants with an animacy manipulation (human and computer-generated stimuli, Experiment 1) and a clarity manipulation (stimuli with varying visual clarity using Gaussian blurring, Experiments 1 and 2) to tease apart effect of these manipulations. Participants in Experiment 1 responded slower for incompatible than for compatible trials, showing a compatibility effect. Experiment 1 found a null effect of animacy, but stimuli with lower visual clarity evoked smaller compatibility effects. Experiment 2 modulated clarity in five steps and reports decreasing compatibility effects for stimuli with lower clarity. Clarity, but not animacy, therefore affected automatic imitation, and theoretical implications and future directions are considered. [ABSTRACT FROM AUTHOR]

Simulation accounts of speech perception posit that speech is covertly imitated to support perception in a top-down manner. Behaviourally, covert imitation is measured through the stimulus-response compatibility (SRC) task. In each trial of a speech SRC task, participants produce a target speech sound whilst perceiving a speech distractor that either matches the target (compatible condition) or does not (incompatible condition). The degree to which the distractor is covertly imitated is captured by the automatic imitation effect, computed as the difference in response times (RTs) between compatible and incompatible trials. Simulation accounts disagree on whether covert imitation is enhanced when speech perception is challenging or instead when the speech signal is most familiar to the speaker. To test these accounts, we conducted three experiments in which participants completed SRC tasks with native and non-native sounds. Experiment 1 uncovered larger automatic imitation effects in an SRC task with non-native sounds than with native sounds. Experiment 2 replicated the finding online, demonstrating its robustness and the applicability of speech SRC tasks online. Experiment 3 intermixed native and non-native sounds within a single SRC task to disentangle effects of perceiving non-native sounds from confounding effects of producing non-native speech actions. This last experiment confirmed that automatic imitation is enhanced for non-native speech distractors, supporting a compensatory function of covert imitation in speech perception. The experiment also uncovered a separate effect of producing non-native speech actions on enhancing automatic imitation effects. [ABSTRACT FROM AUTHOR]

Stimulus-response compatibility (SRC)-the fact that some stimulus-response pairs are faster than others-is attributed in part to automatic activation of the stimulus-compatible response representation. Cognitive models of SRC propose that automatic response activation can be strategically suppressed if the automatic response is likely to interfere with behavior; in particular, suppression is thought to occur in preparation for incompatible responses and when the required stimulus-response mapping is unknown before stimulus presentation. We test this preparatory suppression hypothesis in the context of imitation, a special form of SRC particularly relevant to human social behavior. Using TMS, we measured muscle-specific corticospinal excitability during action observation (motor resonance) while human participants prepared to perform imitative and counterimitative responses to action videos. Motor resonance was suppressed during preparation to counterimitate and for unknown mappings, compared to preparation to imitate and a baseline measure of motor resonance. These results provide novel neurophysiological evidence that automatic activation of stimulus-compatible responses can be strategically suppressed when the automatic response is likely to interfere with task goals. Insofar as motor resonance measures mirror neuron system activity, these results also suggest that preparatory control of automatic imitative tendencies occurs through modulation of mirror neuron system activity.

The tendency to imitate the actions of others appears to be a fundamental aspect of human social interaction. Emotional expressions are a particularly salient form of social stimuli (Vuilleumier & Schwartz, 2001) but their relationship to imitative behaviour is currently unclear. In this paper we report the results of five studies which investigated the effect of a target's dynamic emotional stimuli on participants' tendency to respond compatibly to the target's actions. Experiment one examined the effect of dynamic emotional expressions on the automatic imitation of opening and closing hand movements. Experiment two used the same basic paradigm but added gaze direction as an additional factor. Experiment three investigated the effect of dynamic emotional expressions on compatibility responses to handshakes. Experiment four investigated whether dynamic emotional expressions modulated response to valenced social gestures. Finally, experiment five compared the effects of dynamic and static emotional expressions on participants' automatic imitation of finger lifting. Across all five studies we reliably elicited a compatibility effect however, none of the studies found a significant modulating effect of emotional expression. This null effect was also supported by a random effects meta-analysis and a series of Bayesian t-tests. Nevertheless, these results must be caveated by the fact that our studies had limited power to detect effect sizes below d = 0.4. We conclude by situating our findings within the literature, suggesting that the effect of emotional expressions on automatic imitation is, at best, minimal.

When people take the perspective of an avatar and perform a stimulus-response compatibility task, they generally show the same compatibility effects that are expected from the avatar's position instead of their own. In this study, we investigated if these effects are caused by automatic response activation, a concept featured in dual-route models of stimulus-response compatibility. In two experiments we asked 24 participants each to perform a compatibility task from an avatar's point of view. We introduced a delay between the presentation of the target and the avatar in half of the trials so that the participants had to wait until the avatar appeared to select the correct response. Because the automatic response activation is known to decay quickly, its influence is eliminated in this condition. In contrast to the prediction by the automatic response activation account, we observed a larger compatibility effect in the delayed condition with orthogonal (Experiment 1) and parallel (Experiment 2) stimulus-response pairings. Additionally, distributional analyses of the compatibility effects did not support the automaticity predictions. We conclude that these results call into question the role of automatic response activation for spatial compatibility in general and perspective-based compatibility effects in particular. [ABSTRACT FROM AUTHOR]

• Motivational orientation towards ideal and non-ideal male bodies was examined. • Males demonstrated an approach bias towards the muscular ideal. • There was neither an approach nor avoidance bias regarding non-ideal bodies. • Only approach towards ideal bodies uniquely associated with body dissatisfaction. Internalisation of the muscular ideal is a vulnerability factor for body dissatisfaction in males. It is unclear, however, whether body dissatisfaction results from approach towards the muscular ideal versus fear of the stigmatised burdensome body. The current study sought to address this gap by assessing both approach and avoidance motivation regarding muscular and non-muscular bodies, respectively, and evaluating the unique associations between approach-avoidance tendencies and body dissatisfaction. Eighty-three male undergraduate students completed an implicit measure of approach-avoidance tendencies, the Stimulus Response Compatibility task, and a self-report measure of trait body dissatisfaction. Results revealed that participants were quicker to approach than to avoid muscular bodies; however, there were no differences in approach vs. avoidance tendencies regarding non-muscular bodies. Furthermore, in a multiple regression model comprising motivational bias scores regarding muscular and non-muscular bodies, only an approach bias towards muscular bodies predicted unique variance in body dissatisfaction. These findings are novel in showing an implicit approach motivation towards the muscular ideal in male undergraduates. Furthermore, in this population, motivational orientation towards the muscular ideal, versus the stigmatised burdensome body, seems to be more tightly associated with body dissatisfaction. [ABSTRACT FROM AUTHOR]

Research suggests that responses to pictures of manipulable objects are facilitated when the location of the response is aligned with the side of the object handle. One interpretation of alignment effects is that object identification results in the automatic activation of actions associated with the object. Alignment effects are, however, not ubiquitously found. Yu, Abrams, and Zacks (2014) found an alignment effect when participants were instructed to imagine picking up the pictured objects while making upright-inverted judgments. Six other experiments, which did not use such instructions, found no alignment effect. One interpretation is that motor-imagery instructions draw attention to the graspable parts of an object, which results in the activation of actions associated with the object. This account predicts that alignment effects are restricted to responses with the left and right hand. An alternative interpretation is that motor-imagery instructions result in the formation of abstract spatial codes for left versus right. This spatial coding account predicts that alignment effects are present for other types of responses that involve a left-right dimension. Consistent with the latter account, we found that alignment effects were found even when participants responded with the index and middle finger of the same hand or with their left and right feet. Currently popular accounts of human cognition suggest that the actions associated with objects are automatically activated when one perceives an object. Our study presents evidence against this view. In fact, it suggests that not even when participants are instructed to think how they would pick up an object is such information readily activated. [ABSTRACT FROM AUTHOR]

This study examines the effect of interpolated tasks and gender on adaptation to two altered task components—compatibility and order of control. Participants (20 men, 16 women of college age) directed a cursor onto a circular target on a monitor as quickly as possible. A joystick directed cursor movements, having either position or velocity control order and compatible or incompatible mapping, depending on the testing conditions. Overall, male participants’ movements were faster and more accurate than movements of the female participants. However, female participants’ performance did not significantly differ from that of the male participants when the participants practiced two task factors simultaneously and females benefited significantly more than males from the practice. The testing conditions (context) significantly contributed to the performance differences in female participants. In conclusion socioeconomic and cultural values and subsequent gender roles influence performance differences between men and women in a novel stimulus response compatibility task. Women should be given more freedom, encouragement and positive reinforcement to explore and participate in certain visual spatial tasks during early childhood.

Cultured neurons on multi electrode arrays (MEAs) have been widely used to study various as-pects of neuronal (network) functioning. A possible drawback of this approach is the lack of structure in these networks. At the single cell level, several solutions have been proposed to ena-ble directed connectivity, and promising results were obtained. At the level of connected sub-populations, a few attempts have been made with promising results. First assessment of the de-signs’ functionality, however, suggested room for further improvement.We designed a two chamber MEA aiming to create a unidirectional connection between the net-works in both chambers (‘emitting’ and ‘receiving’). To achieve this unidirectionality, all inter-connecting channels contained barbs that hindered axon growth in the opposite direction (from receiving to emitting chamber). Visual inspection showed that axons predominantly grew through the channels in the promoted direction . This observation was confirmed by spontaneous activity recordings. Cross-correlation between the signals from two electrodes inside the channels suggested signal propagation at ≈2 m/s from emitting to receiving chamber. Cross-correlation between the firing patterns in both chambers indicated that most correlated activity was initiated in the emitting chamber, which was also reflected by a significantly lower fraction of partial bursts (e. a one-chamber-only burst) in the emitting chamber. Finally, electrical stimulation in the emitting chamber induced a fast response in that chamber, and a slower response in the receiving chamber. Stimulation in the receiving chamber evoked a fast response in that chamber, but no response in the emitting chamber. These results confirm the predominantly unidirectional nature of the connecting channels from emitting to receiving chamber.

Responses to objects with a graspable handle are faster when the response hand and handle orientation are aligned (e.g., a key press with the right hand is required and the object handle is oriented to the right) than when they are not aligned. This effect could be explained by automatic activation of specific motor programs when an object is viewed. Alternatively, the effect could be explained by competition at the response level. Participants performed a reach-and-grasp or reach-and-button-press action with their left or right hand in response to the color of a beer mug. The alignment effect did not vary as a function of the type of action. In addition, the alignment effect disappeared in a go/no-go version of the task. The same results were obtained when participants made upright/inverted decisions, so that object shape was task-relevant. Our results indicate that alignment effects are not due to automatic motor activation of the left or right limb. [ABSTRACT FROM AUTHOR]

Does our brain treat non-biological movements (e.g. moving abstract shapes or robots) in the same way as human movements? The current work tested whether the movement of a non-biological rectangular object, believed to be based on a human action is represented within the observer's motor system. A novel visuomotor priming task was designed to pit true imitative compatibility, due to human action representation against more general stimulus response compatibility that has confounded previous belief experiments. Stimulus response compatibility effects were found for the object. However, imitative compatibility was found when participants repeated the object task with the belief that the object was based on a human finger movement, and when they performed the task viewing a real human hand. These results provide the first demonstration that non-biological stimuli can be represented as a human movement if they are believed to have human agency and have implications for interactions with technology and robots. [ABSTRACT FROM AUTHOR]

Theories of embodied cognition suppose that perception, action and cognition are tightly intertwined and share common representations and processes. Indeed, numerous empirical studies demonstrate interaction between stimulus perception, response planning and response execution. In this paper, we present an experiment and a connectionist model that show how the Simon effect, a canonical example of perception-action congruency, can be moderated by the (cognitive representation of the) task instruction. To date, no representational account of this influence exists. In the experiment, a two-dimensional Simon task was used, with critical stimuli being colored arrows pointing in one of four directions (backward, forward, left or right). Participants stood on a Wii balance board, oriented diagonally towards the screen displaying the stimuli. They were either instructed to imagine standing on a snowboard or on a pair of skis and to respond to the stimulus color by leaning towards either the left or right foot. We expected that participants in the snowboard condition would encode these movements as forward or backward, resulting in a Simon effect on this dimension. This was confirmed by the results. The left–right congruency effect was larger in the ski condition, whereas the forward–backward congruency effect appeared only in the snowboard condition. The results can be readily accounted for by HiTEC, a connectionist model that aims at capturing the interaction between perception and action at the level of representations, and the way this interaction is mediated by cognitive control. Together, the empirical work and the connectionist model contribute to a better understanding of the complex interaction between perception, cognition, and action.

Previous studies have shown that viewing body actions primes not only the visual perception of congruent versus incongruent actions, but also their motor execution. Here, we used a masked-priming paradigm to explore whether visuoperceptual and visuomotor action priming may also occur when the prime is not consciously perceived. In 5 experiments, healthy individuals were presented with masked implied-action primes and were then prompted to perceive congruent or incongruent implied-action stimuli or to execute congruent or incongruent finger movements. Results showed that implied-action primes affected subsequent action perception also when they were not consciously perceived. Unconscious visuoperceptual action priming effects were independent from spatial compatibility and reflected genuine action representation. Conversely, masked implied-action primes affected motor preparation and execution processes only when they were consciously perceived. The results provide evidence of unconscious visuoperceptual but not visuomotor action priming effects, suggesting that unconscious processing of actions affects perceptual, but not motor representations. [ABSTRACT FROM AUTHOR]

Abstract: Stimulus–response compatibility (SRC)—the fact that some stimulus–response pairs are faster than others—is attributed in part to automatic activation of the stimulus–compatible response representation. Cognitive models of SRC propose that automatic response activation can be strategically suppressed if the automatic response is likely to interfere with behavior; in particular, suppression is thought to occur in preparation for incompatible responses and when the required stimulus–response mapping is unknown before stimulus presentation. We test this preparatory suppression hypothesis in the context of imitation, a special form of SRC particularly relevant to human social behavior. Using TMS, we measured muscle-specific corticospinal excitability during action observation (motor resonance) while human participants prepared to perform imitative and counterimitative responses to action videos. Motor resonance was suppressed during preparation to counterimitate and for unknown mappings, compared to preparation to imitate and a baseline measure of motor resonance. These results provide novel neurophysiological evidence that automatic activation of stimulus–compatible responses can be strategically suppressed when the automatic response is likely to interfere with task goals. Insofar as motor resonance measures mirror neuron system activity, these results also suggest that preparatory control of automatic imitative tendencies occurs through modulation of mirror neuron system activity. [Copyright &y& Elsevier]

Participants with Down syndrome (DS), and typical chronological and mental age-matched (MA) participants, completed a three movement sequence in response to visual (e.g., illumination of objects), verbal (e.g., name of objects), directly related auditory (e.g., sound of objects), and indirectly related auditory (e.g., different tones for each object) instructions. Our results indicated that participants with DS and the MA group were slowest and made the most errors in the indirectly related auditory condition indicating that the amount of meaning associated with the method of instruction is an important determinant of motor performance in persons with DS and young children. These results demonstrate the importance of auditory stimulus and response compatibility for motor performance, especially in persons with low mental age. [ABSTRACT FROM AUTHOR]

Abstract: Background: Prominent addiction models posit that automatically activated approach/avoidance tendencies play a critical role in addiction. Nevertheless, only a limited number of studies have actually documented the relationship between relapse and automatically activated approach/avoidance tendencies. We compared automatically activated approach/avoidance tendencies towards alcohol in 40 abstaining alcohol-dependent patients and 40 controls. We also examined whether individual differences in automatically activated approach/avoidance tendencies towards alcohol are predictive of relapse in patients. Methods: A Relevant Stimulus Response Compatibility task was used to measure relative approach/avoidance tendencies. In one block of trials, participants were asked to approach alcohol-related pictures and to avoid alcohol-unrelated pictures (i.e., compatible block). In a second block of trials, participants were asked to approach alcohol-unrelated pictures and to move away from alcohol-related pictures (i.e., incompatible block). Patients were tested between 18 and 21 days after they quit drinking. Relapse was assessed 3 months after patients were discharged from the hospital. Results: Whereas abstaining alcohol-dependent patients were faster to respond to incompatible trials as compared to compatible trials, participants in the control group showed the exact opposite pattern. Within the patient group, the likelihood of relapse increased as participants were faster to respond to incompatible trials relative to compatible trials. Conclusions: Unlike controls, abstaining alcohol-dependent patients revealed a relative avoidance bias rather than relative approach bias. Moreover, relapse rates were found to increase as the relative tendency to avoid alcohol increased. This finding suggests that an avoidance orientation towards alcohol can potentially be harmful in clinical samples. [Copyright &y& Elsevier]

Imitative compatibility, or automatic imitation, has been used as a measure of imitative performance and as a behavioral index of the functioning of the human mirror system (e.g., Brass, Bekkering, Wohlschlager, & Prinz, 2000; Heyes, Bird, Johnson, & Haggard, 2005; Kilner, Paulignan, & Blakemore, 2003). However, the use of imitative compatibility as a measure of imitation has been criticized on the grounds that imitative compatibility has been confounded with simple spatial compatibility (Aicken, Wilson, Williams, & Mon-Williams, 2007; Bertenthal, Longo, & Kosobud, 2006; Jansson, Wilson, Williams, & Mon-Williams, 2007). Two experiments are reported in which, in contrast with previous studies, imitative compatibility was measured on both spatially compatible and spatially incompatible trials, and imitative compatibility was shown to be present regardless of spatial compatibility. Additional features of the experiments allowed measurement of the time courses of the imitative and spatial compatibility effects both within and across trials. It was found that imitative compatibility follows a different time course from spatial compatibility, providing further evidence for their independence and supporting the use of imitative compatibility as a measure of imitation. [ABSTRACT FROM AUTHOR]

Abstract: Observation of human actions influences the observer’s own motor system, termed visuomotor priming, and is believed to be caused by automatic activation of mirror neurons. Evidence suggests that priming effects are larger for biological (human) as opposed to non-biological (object) stimuli and enhanced when viewing stimuli in mirror compared to anatomical orientation. However, there is conflicting evidence concerning the extent of differences between biological and non-biological stimuli, which may be due to stimulus related confounds. Over three experiments, we compared how visuomotor priming for biological and non-biological stimuli was affected over views, over time and when attention to the moving stimulus was manipulated. The results indicated that the strength of priming for the two stimulus types was dependent on attentional location and load. This highlights that visuomotor priming is not an automatic process and provides a possible explanation for conflicting evidence regarding the differential effects of biological and non-biological stimuli. [Copyright &y& Elsevier]

Participants indicated whether a small dot was located near the top or bottom pole of a rotated object. Response times increased as a function of object orientation more for top trials than for bottom trials. The interaction between orientation and response was shown to be due to a relationship between response times and the dot's height on the screen. The orientation effect was influenced, positively and negatively, by a vertical arrangement of the response keys depending on whether the upper or lower key was used for the top response. Horizontal key placement produced an intermediate orientation effect, with asymmetries of about 180° depending on which hand was used for top responses. This task appears to reflect spatial stimulus-response compatibilities more than object processing. [ABSTRACT FROM AUTHOR]

The tendency to imitate the actions of others appears to be a fundamental aspect of human social interaction. Emotional expressions are a particularly salient form of social stimuli (Vuilleumier & Schwartz, 2001) but their relationship to imitative behaviour is currently unclear. In this paper we report the results of five studies which investigated the effect of a target's dynamic emotional stimuli on participants' tendency to respond compatibly to the target's actions. Experiment one examined the effect of dynamic emotional expressions on the automatic imitation of opening and closing hand movements. Experiment two used the same basic paradigm but added gaze direction as an additional factor. Experiment three investigated the effect of dynamic emotional expressions on compatibility responses to handshakes. Experiment four investigated whether dynamic emotional expressions modulated response to valenced social gestures. Finally, experiment five compared the effects of dynamic and static emotional expressions on participants' automatic imitation of finger lifting. Across all five studies we reliably elicited a compatibility effect however, none of the studies found a significant modulating effect of emotional expression. This null effect was also supported by a random effects meta-analysis and a series of Bayesian t -tests. Nevertheless, these results must be caveated by the fact that our studies had limited power to detect effect sizes below d = 0.4. We conclude by situating our findings within the literature, suggesting that the effect of emotional expressions on automatic imitation is, at best, minimal. • The effect of emotional expressions on automatic imitation is currently unclear. • We used dynamic expressions to investigate this effect across five experiments. • We found that the expressions did not affect the imitation of response to gestures. • This was the case even when the gestures had affective or social meaning. [ABSTRACT FROM AUTHOR]

This study examines the effect of interpolated tasks and gender on adaptation to two altered task components&#x2014.compatibility and order of control. Participants (20 men, 16 women of college age) directed a cursor onto a circular target on a monitor as quickly as possible. A joystick directed cursor movements, having either position or velocity control order and compatible or incompatible mapping, depending on the testing conditions. Overall, male participants’ movements were faster and more accurate than movements of the female participants. However, female participants’ performance did not significantly differ from that of the male participants when the participants practiced two task factors simultaneously and females benefited significantly more than males from the practice. The testing conditions (context) significantly contributed to the performance differences in female participants. In conclusion socioeconomic and cultural values and subsequent gender roles influence performance differences between men and women in a novel stimulus response compatibility task. Women should be given more freedom, encouragement and positive reinforcement to explore and participate in certain visual spatial tasks during early childhood. [ABSTRACT FROM AUTHOR]

Performance on cognitive control tasks deteriorates when control tasks are performed together with other control tasks, that is, if simultaneous cognitive control is required. Surprisingly, this is also observed if control tasks are preceded by other control tasks, that is, if sequential cognitive control is required. The typical explanation for the latter finding is that previous acts of cognitive control deplete a common resource, just like a muscle becomes fatigued after repeated usage. An alternative explanation, however, is that previous acts of cognitive control reduce motivation to match allocated resources to required resources. In this paper we formalize these muscle and motivation accounts, and show that they yield differential predictions regarding the interaction between simultaneous and sequential cognitive control. These predictions were tested using a paradigm where participants had to perform multiple stop-signal tasks, which varied in their demands on simultaneous and sequential control. Results of two studies supported predictions derived from the motivation account. Therefore, we conclude that the effects of sequential cognitive control are best explained in terms of a reduction of motivation to match allocated to required resources.