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Intolerance of uncertainty is an empirically supported transdiagnostic construct that may have relevance in understanding eating disorders. We conducted a meta-analysis and systematic review of intolerance of uncertainty in eating disorders using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We calculated random-effects standardised mean differences (SMD) for studies utilising the Intolerance of Uncertainty Scale (IUS) and summarised additional studies descriptively. Women with eating disorders have significantly higher IUS scores compared with healthy controls (SMD = 1.90; 95% C.I. 1.24 to 2.56; p

The present study aimed at determining whether the observation of two functionally compatible artefacts, that is which potentially concur in achieving a specific function, automatically activates a motor programme of interaction between the two objects. To this purpose, an interference paradigm was used during which an artefact (a bottle filled with orange juice), target of a reaching-grasping and lifting sequence, was presented alone or with a non-target object (distractor) of the same or different semantic category and functionally compatible or not. In experiment 1, the bottle was presented alone or with an artefact (a sphere), or a natural (an apple) distractor. In experiment 2, the bottle was presented with either the apple or a glass (an artefact) filled with orange juice, whereas in experiment 3, either an empty or a filled glass was presented. In the control experiment 4, we compared the kinematics of reaching-grasping and pouring with those of reaching-grasping and lifting. The kinematics of reach, grasp and lift was affected by distractor presentation. However, no difference was observed between two distractors that belonged to different semantic categories. In contrast, the presence of the empty rather filled glass affected the kinematics of the actual grasp. This suggests that an actually functional compatibility between target (the bottle) and distractor (the empty glass) was necessary to activate automatically a programme of interaction (i.e. pouring) between the two artefacts. This programme affected the programme actually executed (i.e. lifting). The results of the present study indicate that, in addition to affordances related to intrinsic object properties, "working affordances" related to a specific use of an artefact with another object can be activated on the basis of functional compatibility.

An experiment investigated the ability by human observers to detect temporal reversals in dynamic displays of human locomotion. We video-taped the lower portion of the body of actors walking at their preferred speed either in the normal, forward direction (FW) or in the backward direction (BW). The videos were presented in a random order either as recorded (N) or in reverse (R). In one session, we presented both normal and time-reversed stimuli in the original upright orientation. In a second session, the stimuli were rotated by 180° around the horizontal axis. Observers were informed that the real recorded movement was either forward or backward and were asked to decide whether or not the movement had been time-reversed prior to the presentation. Although the kinematics of forward and backward human locomotion is quite similar, the detection of temporal reversals followed a consistent pattern showing a good accuracy in condition FW-N and a reduced but still above-chance performance in condition BW-R (by design, in both conditions actors appeared to walk forward). Performance was instead at chance level in the other two conditions where the apparent direction of the movement was backward. Inverting the spatial orientation of the stimuli reduced but did not suppress the ability to detect temporal reversals in the two conditions with apparent forward direction of movement. It is argued that implicit motor competence is at least in part instrumental for extracting the subtle discriminal information from the stimuli.

The present study aimed at determining whether, and in what conditions, covert imitation of different manual grasps of the same object influences estimation of those object properties whose variations afford those different grasp interactions. Participants matched the size of spheres after observation of the same spheres being grasped using both a power and a precision grasp: these actions are used preferentially to grasp large and small objects, respectively. The type of matching varied across four experiments. In experiment 1, participants matched the object size by opening their thumb and index finger; in experiment 2, they abducted their index and middle fingers as in a finger opening of a cutting pantomime, and in experiment 3, they opened their mouth. In experiment 4, the sphere size was reproduced on a PC monitor by moving the mouse forward/backward. Grasp observation affected matching in experiments 1 and 3. Kinematics analysis showed overestimation after observation of a power grasp as compared to a precision grasp. The data are interpreted as a consequence of covert imitation of the observed hand kinematics, which varied congruently with the object sizes potentially activating that type-of-grasp. This affected estimation of object size. Covert imitation was favored by the types of matching requiring motor patterns related to grasp movements independently of the effector used. This finding supports the existence of motor commands to the hand as well as to the mouth, activated when the same potential goal guides the movements of both these effectors.

The present study aimed at determining whether or not the comprehension of symbolic gestures, and corresponding-in-meaning words, makes use of cortical circuits involved in movement execution control. Participants were presented with videos of an actress producing meaningful or meaningless gestures, pronouncing corresponding-in-meaning words or pseudo-words; they were required to judge whether the signal was meaningful or meaningless. Single pulse TMS was applied to forearm primary motor cortex area 150–200 ms after the point when the stimulus meaning could be understood. MEPs were significantly greater when processing meaningless signals as compared to a baseline condition presenting a still-and-silent actress. In contrast, this was not the case for meaningful signals whose motor activation did not differ from that for the baseline stimulus. MEPs were significantly greater for meaningless than meaningful signals and no significant difference was found between gesture and speech. On the basis of these results, we hypothesized that the observation-of/listening-to meaningless signals recruits motor areas. In contrast, this did not occur when the signals were meaningful. Overall, the data suggest that the processes related to comprehension of symbolic gestures and communicative words do not involve primary motor area and probably use brain areas involved in semantics.

Using transcranial magnetic stimulation (TMS), motor evoked potentials (MEPs) were recorded from two antagonistic muscles, the first dorsal interosseus (FDI) of the hand and the extensor communis digitorum (EC) of the forearm. FDI is involved in grasping actions and EC in releasing. TMS pulses were delivered while participants were reading adjectives expressing either negative or positive pragmatic properties, at 150 ms after presentation of language material. Overall findings showed an interaction of adjective type (positive, negative) and muscle (FDI, EC), the effect being driven by a significant difference for negative adjectives. Further analysis aimed at investigating the effectiveness of positive adjectives showed a similar, but opposite, pattern of effects for the positive words in the initial two blocks. The present results indicate that, as for verbs and nouns, adjectives recruit the sensorimotor system, and their processing is best explained by an embodiment rather than an amodal approach to language.

We tested whether a system coupling hand postures related to gestures to the control of internal mouth articulators during production of vowels exists and it can be precursor of a system relating hand/arm gestures to words. Participants produced unimanual and bimanual representational gestures expressing the meaning of LARGE or SMALL. Once the gesture was produced, in experiment 1 they pronounced the vowels “A” or “I”, in experiment 2 the word “GRANDE” (large) or “PICCOLO” (small), and in experiment 3 the pseudo-words “SCRANTA” or “SBICCARA”. Mouth, hand kinematics and voice spectra were recorded and analyzed. Unimanual gestures affected voice spectra of the two vowels pronounced alone (experiment 1). Bimanual and both unimanual and bimanual gestures affected voice spectra of /a/ and /i/ included in the words (experiment 2) and pseudo-words (experiment 3), respectively. The results support the hypothesis that a system coupling hand gestures to vowel production exists. Moreover, they suggest the existence of a more general system relating gestures to words.

Is the human kinematics automatically imitated when an individual observes transitive actions (i.e. directed upon an object) executed with different effectors and then executes either the same or a different action? In three experiments participants executed actions of reaching-grasping after observation of reaching-grasping, bringing-to-the-mouth, foot-touching, and arrow-touching. Both power and precision interactions were presented. The kinematics of all movements was those typical of humans. The observed variations in velocity due to the type of interaction were imitated when an interacting biological effector (i.e. arm, mouth and foot) was presented. In contrast, no imitation was observed when a non-biological effector (i.e. the arrow) was presented. The results of the present study suggest that there exists a kinematic representation of the rules governing the types of interaction of biological effectors with objects. It is automatically activated by action observation and affects kinematic landmarks of the successive action, i.e. the peak velocities and accelerations. This representation is common to different biological effectors probably because it shares the aim of those actions.

Both intersubjectivity and embodied cognitive processes are based on mechanisms for sharing actions, common to the species. The evolution of spoken language and of communication systems in general are good examples of this. In the present review, we propose that, by a process of observation and imitation, the sharing of object-directed actions (i.e., transitive arm/hand actions) and their pantomimes could have been used to progressively construct communication systems capable of representing action meaning (i.e., their goals). Starting from this process of observation and imitation, humans may have constructed progressively more complex communication systems based on iconic and symbolic arm gestures. These communication systems may have gradually been translated into more specific, buccal, gesture-based systems that gave rise to spoken language. In support of these hypotheses, we report evidence showing that the execution and observation of transitive actions and their pantomimes affects the production of phonological units. We describe the effects of the production and observation of symbolic gestures on word pronunciation. Finally, we report evidence that these systems relating gesture to speech have neural correlates in neural circuits located in the frontal cortex, understood to be involved in spoken language..