This thesis contains a set of empirical investigations, which explore a fundamental issue in human communication, namely the functional significance of iconic hand gestures that accompany speech. Some researchers argue that these iconic gestures function for the speaker to facilitate lexical retrieval from the mental lexicon (e.g. Butterworth and Hadar, 1989; 1997). An alternative theory is that these iconic gestures are to do with the communication of information from a speaker to a listener (e.g. McNeill, 1985; 1992). This important debate forms the basis of the current research. The research reported in this thesis was found to provide little evidence for the lexical access theoretical position but provide important supporting evidence for the argument that iconic gestures are essentially communicative. It has shown convincingly that information about the world out there is encoded into speech and gesture and seems to provide a substantial body of evidence that iconic gestures do indeed convey semantic information to respondents. It has also shown that some iconic gestures are more communicative than others and that the occurrence of these gestures is affected by certain identifiable properties of talk. One of the strengths of the current research is that it is now more precisely known what semantic information is actually received by respondents from gesture and hence this research provides a much better insight into how the linguistic and gestural codes interact in the communication of meaning. The research reported in this thesis suggests that those researchers who neglect iconic gesture in their study of how language is used in eveiyday life are missing a major component of the process of human communication.

Embodied Cognition accounts propose that motor activation contributes to semantic representations in action language (Fischer & Zwaan, 2008). However, the nature of this activation remains largely unspecified: in particular, which processes result in relevant activation? Long-term motor experience (e.g., the comprehender’s dominant hand), short-term motor experience (e.g., the hand the comprehender has recently used), and action planning (e.g., the hand the comprehender is planning to use) are all potential candidates. This thesis uses a range of psycholinguistic methods (e.g., timed sentence-picture matching, two-alternative forced-choice sentence-picture matching, spoken sensibility judgements) to distinguish between these possibilities. A first set of experiments investigated how comprehenders’ handedness affects their interpretation of sentences describing manual actions (e.g., I am slicing the tomato). Participants matched sentences of actions to pictures of that action. The Body-Specificity Hypothesis (Casasanto, 2009; Willems, Hagoort, & Casasanto, 2010) predicts that right-handed and left-handed comprehenders will interpret manual action sentences differently, according to whether they would perform that action with their right or their left hand. However, we found that comprehenders appear to interpret manual action sentences according to the hand they use to respond to the task, and not the hand they would typically use to perform manual actions. In addition, this effect was stronger for first-person than third-person sentences, implying that the effect of motor activation is moderated by linguistic context. A second set of experiments used the same paradigm but manipulated at what point comprehenders knew which hand they would use to respond to the sentences: during sentence processing, or after sentence processing was complete. We replicated the finding that comprehenders interpret manual action sentences according to their response hand, and that this effect was stronger for first- than for third-person sentences; but only when comprehenders knew their response hand during sentence processing. In both sets of experiments, there was no effect of whether the picture of the action was presented from an egocentric or allocentric perspective, implying that action sentences are encoded for what effector (in this case, hand) will be used in the action, but not necessarily from what perspective the action will occur. A third set of experiments investigated the existence of a causal role of action planning-based activation on sentence processing. Many studies have shown an effect of language processing on action execution (e.g., Glenberg & Kaschak, 2002; Glenberg et al., 2008), but a fully embodied theory of language also predicts an effect of motor activation on language processing. Here, right-handed participants made spoken judgements about sentences while planning an action with their right or left hand that matched or did not match the action described in the sentence. An effect of response hand on accuracy was found when the task required participants to explicitly judge the congruency of sentence and the action they were preparing, but not otherwise. These results corroborate recent research suggesting that activation of embodied lexical representations may be goal-driven rather than an automatic aspect of language processing (Hoedemaker & Gordon, 2013). Overall, the experiments presented in this thesis suggest a possible role for planning-based motor activation in sentence processing, in line with embodied approaches; however, the results challenge strong accounts of embodiment by suggesting that the effect of planning-based activation is not automatic, and is moderated by linguistic context and task demands.

No description available.

The way we act upon the world influences our visual perception of it. For instance, previous work has found visual perceptual enhancement at the targets of upcoming saccades (e.g. Deubel & Schneider, 1996) and pointing movements (e.g. Deubel, Schneider, & Paprotta, 1998). Visual perceptual enhancement has also been found along the trajectories of manual movements (Festman, Adam, Pratt, & Fischer, 2013a, 2013b), but the area surrounding static hands have also been found to receive perceptual enhancement (Reed, Grubb, & Steele, 2006). The initial question addressed by the present thesis was whether the preparation of a manual movement would also induce perceptual enhancement at the effector location (i.e. the movement’s start point). In other words, do people not only attend where they are going, but also where they are coming from? To address this question, the novel aspect of our task was that participants not only had to select the movement target, but also the moving hand. Across the eight experiments of the present thesis we applied variations on a popular experimental task, asking our participants to conduct pointing movements and studying how this influenced their allocation of visuospatial attention. This was measured by recording whether they could successfully identify a discrimination target (DT), with the discrimination rates at different locations taken to index the amount of attention allocated there. Our first four experiments found evidence for enhancement at the starting point of a movement, but this effect was inconsistent and appeared to compete with other mechanisms for orienting attention. For example, our first experiment found enhancement only at the target location, which may have been induced by having used predictable locations for the DT, whereas Experiment 4 found only an enhancement at both hands, static and responding, which might have been due to the ability to plan the movements in advance. Since in each trial in Experiment 4 participants had to execute one movement out of only two possibilities, this may have allowed them to pre-program both movements before each trial and execute them from memory. In Experiment 5 we increased the number of potential movement targets in order to increase the difficulty of target selection and reduce movement predictability, while also lowering the DT presentation times. Under this more challenging paradigm we found perceptual enhancement only at the movement target, but also that the perceptual task was too difficult for half of our participants. Did we fail to induce enhancement at multiple locations because of the specific task our participants were executing, or due to a general inability to do so within this more challenging version of the experimental paradigm? To address this question we decided to test whether we could still induce perceptual enhancement at two locations within these experimental parameters, but attempting to replicate the work of Baldauf, Wolf and Deubel (2006). They had reported that carrying out pointing sequences resulted in parallel allocation of attention to all movement targets before movement onset. We repeatedly failed to find any enhancement at any location, even when we increased the presentation times to durations used in the earlier experiments. In our final experiment we mounted a more direct replication of Baldauf et al (2006), and we also conducted a preliminary calibration stage in which we attempted to adjust the DT’s presentation time to each participant’s level of ability by assessing their perceptual performance. This calibration was only successful in a third of our participants, with the majority still finding the perceptual task too challenging within the range of exposure times used. Furthermore, even amongst those participants selected for their good perceptual performance in the calibration task, we found visual enhancement only at the first movement target during the two-step pointing sequence. This calls into question not only the general replicability of the work of Baldauf et al. (2006), but also Deubel et al. (1998). On the whole, our findings suggest that although the pattern of attentional allocation is influenced by action planning, including the starting point of a movement, this is but one of many competing factors. Furthermore they call into question the general replicability of previous high-profile results, and call for a greater acknowledgement and investigation of the possible role of extensive practice in yielding some of the results found in the literature. The thesis concludes with suggestions for future work.

Previous research has demonstrated a retrieval-induced forgetting effect for verbal material (Anderson & Spellman, 1995), colours and shapes (Ciranni & Shimamura,1999), eyewitness testimony (MacLeod, 2002), and images of novel actions (Koutstaal et al., 1999). However, little research has been conducted into retrieval-induced forgetting and self-performed actions. A recent study by Sharman (2011) demonstrated retrieval-induced forgetting for familiar and bizarre self-performed actions. The current thesis aims to examine retrieval-induced forgetting and actions including self-performed and observed actions, and combinations of self-performed and observed actions. The first experiment demonstrated retrieval-induced forgetting for novel motor sequences. In addition, retrieval-induced forgetting was also found for less novel actions (Experiments 3 and 4) for both typical and non-typical self-performed actions (Experiment 3) and memorable self-performed actions (Experiment 4). Experiment 2 demonstrated a retrieval-induced forgetting effect for objects associated with actions suggesting that retrieval-induced forgetting effects occur both for the action and the object. However the findings of experiment 5 suggest that retrieval-induced forgetting may not occur for goal-orientated actions. These experiments may suggest that retrieval-induced forgetting occurs for non goal-orientated actions, but may not occur for goal-orientated actions. These findings are discussed in terms of the inhibitory account.

The optimal performance of an action depends to a great extend on the ability of a person to prepare in advance the appropriate kinetic and kinematic parameters at a specific point in time in order to meet the demands of a given situation and to foresee its consequences to the surrounding environment. In the research presented in this thesis, I employed high-density electroencephalography in order to study the neural processes underlying preparation for action. A typical way for studying preparation for action in neuroscience is to divide it in temporal preparation (when to respond) and event preparation (what response to make). In Chapter 2, we identified electrophysiological signs of implicit temporal preparation in a task where such preparation was not essential for the performance of the task. Electrophysiological traces of implicit timing were found in lateral premotor, parietal as well as occipital cortices. In Chapter 3, explicit temporal preparation was assessed by comparing anticipatory and reactive responses to periodically or randomly applied external loads, respectively. Higher (pre)motor preparatory activity was recorded in the former case, which resulted in lower post-load motor cortex activation and consequently to lower long-latency reflex amplitude. Event preparation was the theme of Chapter 4, where we introduced a new method for studying (at the source level) the generator mechanisms of lateralized potentials related to response selection, through the interaction with steady-state somatosensory responses. Finally, in Chapter 5 we provided evidence for the existence of concurrent and mutually inhibiting representations of multiple movement options in premotor and primary motor areas.

Attentional focus research has reliably demonstrated that an external (beyond the body) focus is superior in terms of skill performance, retention and transfer relative to an internal conscious focus on movement mechanics. This thesis extends current knowledge by evaluating the impact of external focus distance on the performance of continuous skills in an applied context. Specifically, two external focus points of different distances were compared to an undirected attention condition. Three separate studies were conducted using different kayak sprinting disciplines; two of these took place in benign environments using relatively closed skills whilst the third was carried out in an open skill context. In all cases a within-participants experimental design was employed with an independent variable of conscious focus and a dependent variable of performance time. In Study 1, using competent, experienced kayakers (n = 20) in a surf ski sprinting task, the distal external condition significantly outperformed both the undirected focus and proximal external conditions (p < .001 in both cases). The undirected focus condition was significantly faster than the proximal external focus condition (p = .003). The effect size was large (ηp2 = .55). Study 2 examined the same attentional points using youth racers in K1 sprint kayaks (n = 16). The undirected focus condition was significantly faster than the proximal external condition (p = .028); the effect size was large (ηp2 = .23). In Study 3 experienced kayakers (n = 27) were tested in a wild water racing task against the same experimental conditions. The distal external focus condition significantly surpassed both the proximal external condition and the undirected focus condition (p < .001 in both cases). The effect size was large (ηp2 = .53). The studies in this thesis show that the distance of a specified external focus is important and can have a significant influence on performance. In contrast to previous work the proximal external focus did not provide a performance advantage relative to an undirected focus condition; in studies 1 and 2 it was actually detrimental. A distal external focus was beneficial compared to both other conditions in two studies and insignificantly different to the undirected focus trial in Study 2. This thesis brings together work on focus distance and skill type in three applied and non-contrived sporting contexts. The main practical implication of this research is that distance of focus should be considered by learners and coaches with a view to optimising conscious attention. A distal external focus appears to be particularly useful in targeting attention on a pertinent point whilst simultaneously excluding cognitive competition, distractions and unnecessary attentional switching which could undermine skilled performance.

It is still controversial whether mental practice – the internal rehearsal of movements to improve later performance – relies on processes engaged during physical motor performance and, if so, which processes these are. This series of experiments investigates this question. It utilizes a framework of ideomotor action planning theories, and tests whether mental practice may specifically draw upon planning- rather than execution-related motor processes, specifically those processes that “bind” intended action features to action plans. Experiments 1 to 4 utilize a classical stimulus response compatibility paradigm. Participants mentally practiced complex rhythms with either feet or hands while using the same or different body parts to respond to unrelated sounds. In contrast to previous work on stimulus response compatibility, we indeed found that responses were impaired – rather than facilitated – for those body parts that were concurrently used in mental practice. This result was found when participants mentally trained to memorize the rhythms (Experiment 1), to merely improve their performance (Experiment 3), when mental practice and execution directly followed one another and when separated by a different task (Experiment 4). These data link mental practice not to execution but planning related motor processes that are involved in binding intended action features to intended action plans. Experiment 5 and 6 then extend these results to imitation learning. Participants were instructed to learn the rhythms by observing somebody else, while again making unrelated responses with their hand and feet. While previous work on stimulus response compatibility focussed on testing automatic imitation processes, here imitation was therefore goal directed. We found, as in the previous experiments, that responses with the same body parts as used in the observed rhythms were impaired, suggesting that goal-directed imitation might rely on the same planning-related motor processes as the mental practice of action (Experiment 5). Importantly, these effects were only found as long as participants observed the actions with VI the purpose of imitating them later (i.e. formed action plans), but not when they merely tried to memorize the rhythms for later recognition (Experiment 6). The previous experiments suggest that mental practice and observation learning draw upon body-part specific planning processes. Ideomotor theories suggest, however, that action plans can be relatively abstract, and represented in terms of higher-level goals (i.e. the sequence of left and right button presses independent of the body part used). Experiment 7 and 8 therefore tested whether rhythms learned through mental practice or observation learning could be transferred to other body parts. As expected, we found a relatively high amount of potential transfer when rhythms were mentally practiced with one body part, and then had to be transferred to another body part (Experiment 7). However, this only held when participants learned the rhythms based on an abstract rhythm description, as in Experiments 1 to 4. If participants learned the same rhythms during action observation, any benefits were only obtained when the rhythms later had to be executed with the same (rather than a different) body part. Together, the present data suggest that mental practice does not rely on execution related-motor processes, and points to an involvement of planning related motor processes instead. We argue that such a planning-based account of mental practice is more compatible with the available evidence from body neuroscientific and behavioral studies, and allows one to resolve several debates. Moreover, it allows one to conceptualize goal-directed imitation in a similar manner as mental practice.

Les troubles spécifiques du développement praxique (ou gestuel) sont diagnostiqués comme Dyspraxie ou Trouble de l’Acquisition de la Coordination (TAC). Leur compréhension se heurte à de nombreuses impasses, et dans la définition des concepts de praxies et de coordination motrice et dans l’analyse théorique des déficits qu’ils recouvrent. En l’absence de théorie spécifique à l’enfant, les connaissances concernant le développement atypique des praxies se sont élaborées sur une transposition des modèles « adulte » mais sans en appréhender la pertinence. L’objectif principal ici est de dégager les arguments qui étayeraient l’hypothèse d’un trouble spécifique du développement praxique. Le parti est pris de proposer un examen fondé sur les théories du geste chez l’adulte, et qui cible les différents niveaux cognitifs engagés dans son développement: fonctions perceptives (visuelles, spatiales), exécutives (planification, flexibilité, inhibition) et compréhension orale. Les performances d’enfants diagnostiqués dyspraxiques ou TAC et au développement typique sont comparées dans deux études, de groupes puis de cas multiples. Nos résultats montrent des troubles divers « dans » la production du geste, inconstants dans les profils individuels, et associés avec des déficits non spécifiquement gestuels (perceptifs, exécutifs ou de compréhension). Face à cette hétérogénéité, la thèse propose de déconstruire la conception des troubles spécifiques du développement praxique, au profit d’une analyse qui ne confonde pas un trouble « du » geste avec tout déficit se manifestant « dans » le geste. / Specific deficit in praxic (or gestural) development are diagnosed as Dyspraxia or Developmental Coordination Disorder (DCD). Understanding them proves problematic, both when defining the concepts of praxis/motor coordination and when providing a theoretical analysis of the deficits they cover. In the absence of theory specifically related to children, knowledge about atypical development of praxis is gleaned by applying « adult » models, without really understanding whether this is appropriate. The aim of this thesis is to explore the arguments underlying the hypothesis of a specific deficit in praxis development. Tasks were selected based on adult cognitive models of praxis processing in order to enable a comprehensive and theoretically analysis of gestures. We also examined different cognitive functions involved in the praxis development: perception (both visual and spatial), executive functions (planning, flexibility, inhibition) and oral comprehension. The performance of children diagnosed as dyspraxic or DCD is compared to those considered to show typical development in two studies: on groups and multiple case studies. Our results show various difficulties in producing gestures, mostly inconstant in case studies, and related to deficits that are not specifically gestural. Given the heterogeneity of the disorders that we found, this thesis is aimed at deconstructing the concept of specific deficit in praxis development in favour of an analysis that does not confuse gestural problems with other deficits made apparent through gesture.

Notre étude portait sur la similarité fonctionnelle entre mode réel et mental au niveau de la perception et la production spatiotemporelle par le biais d’une tâche continue et répétitive.L’hypothèse était que, lors de l’utilisation de la même tâche motrice en deux modes d’action, la différence d’implication de l’horloge interne et/ou de programme moteur va engendrer une différence entre les patterns des mouvements ainsi qu’une différence dans la perception et la précision spatio-temporelle dans chacun des deux modes d’action.D’après les résultats, il s’avère que les modes mental et réel partagent la même échelle de temps. Le tempo a significativement affecté la perception temporelle en mode réel et mental. Des effets de surestimation avec le tempo rapide ont été retenus pour les deux modes d’action. Cela appuie notre hypothèse secondaire, à savoir «L’amplification des feedbacks sensoriels périphériques est de nature à faciliter un contrôle impulsionnel du temps malgré une exécution de mouvements continus. Les caractéristiques des mouvements (vitesse, variabilité de la forme, précision spatiotemporelle) seront donc modifiées par la présence de Feedback périphérique de nature impulsionnelle »Cependant, le fait de donner des Feedback auditif, tactile ou les deux combinés ne joue pas significativement sur les patterns produits par les sujets. Cela va à l’inverse de notre hypothèse principale qui prévoyait des perceptions spatiotemporelles différentes entre les deux modes selon le Feedback employé. / Our study focused on the functional similarity between the spatiotemporal perception and production, in real and mental execution of ellipses drawing as a continuous and repetitive task.We hypothesized that the same motor task in mentally or real produced action would generate different patterns of movement (spatiotemporal precision) and different time perceptions.According to the results, it seems that the mental and real modes share the same time scale. The tempo has significantly affected the temporal perception in real and mental mode. Overestimation of time was present in both modes of action.These data support our secondary hypothesis "The amplification of peripheral sensory feedback is likely to facilitate impulse control time despite an execution of continuous movements.The movement characteristics (speed, shape variability, precision spatiotemporal) will therefore be modified by the presence of feedback periphery with impulse nature".