During speech perception listeners receive both linguistic information about the speech content as well as information regarding the identity of the talker. While these two aspects have been traditionally studied in isolation, with a dominant interest for linguistic information over talker identity, it is now a widely accepted notion that these two kinds of information are processed in an integrated way. The inclusion of talker-related information in the domain of speech perception highlighted both benefits and challenges for listeners. On the one hand, linguistic and talker-identity information appear to be mutually beneficial for the extraction of both kinds of information from the speech signal. On the other hand, listeners must take care of the great acoustic variability that characterizes the physical dimensions linked to the two kinds of information. The aim of the present dissertation is to study three specific cognitive mechanisms that listeners can use to access the benefits of the integrated processing of linguistic and talker-related information as well as to deal with their intrinsic variability. Three empirical studies employing both behavioural and neurophysiological techniques highlight peculiar aspects of abstraction, memory retrieval and perceptual learning mechanisms in relation to the consequences of including the talker in the study of speech perception.

When we observe other people's actions, a network of temporal, parietal and frontal regions is recruited, known as action observation network (AON). This network includes areas that have been reported to be involved when we perform actions ourselves. Such findings support the view that action understanding occurs by simulating actions in our own motor system (motor theories of action understanding). Alternatively, it has been argued that actions are understood based on a perceptual analysis, with access to action knowledge stored in the conceptual system (cognitive theories of action understanding). It has been argued earlier that areas that play a crucial role for action understanding should be able to (a) distinguish between different actions, and (b) generalize across the ways in which the action is performed (e.g. Dinstein, Thomas, Behrmann, & Heeger, 2008; Oosterhof, Tipper, & Downing, 2013; Caramazza, Anzelotti, Strnad, & Lingnau, 2014). Here we argue that one additional criterion needs to be met: an area that plays a crucial role for action understanding should have access to such abstract action information early, around the time when the action is recognized. An area that has access to abstract action information after the action has been recognized is unlikely to contribute to the process of action understanding. In this thesis, I report three neuroimaging studies in which we used magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) to characterize the temporal dynamics of abstract representations of observed actions (Study 1 and 2), meaning that generalize across lower level dimensions, and to characterize the type of information encoded in the regions of the AON (Study 3). Specifically, in Study 1 we examined where in the brain and at which point in time it is possible to distinguish between pointing and grasping actions irrespective of the way in which they are performed (reach direction, effector) using MEG in combination with multivariate pattern analysis (MVPA) and source analysis. We show that regions in the left lateral occipitotemporal cortex (LOTC) have the earliest access to abstract action representations. By contrast, precentral regions, though recruited relatively early, have access to abstract action representations substantially later than left LOTC. In Study 2, we tested the temporal dynamics of the neural decoding related to the oscillatory activity induced by observation of actions performed with different effectors (hand, foot). We observed that temporal regions are able to discriminate all the presented actions before effector-related decoding within effector-specific motor regions. Finally, in Study 3 we investigated what aspect of an action is encoded within the regions of the AON. Object-directed actions induce a change of states, e.g. opening a bottle means changing its state from closed to open. It is still unclear how and in which brain regions these neural representations are encoded. Using fMRI-based multivoxel pattern decoding, we aimed at dissociating the neural representations of states and action functions. Participants observed stills of objects (e.g., window blinds) that were in either open or closed states, and videos of actions involving the same objects, i.e., open or close window. Action videos could show the object manipulation only (invisible change), or the complete action scene (visible change). This design allowed us to detect neural representations of action scenes, states and action functions independently of each other. We found different sub-regions within LOTC containing information related to object states, action functions, or both. These findings provide important information regarding the organization of action semantics in the brain and the role of LOTC in action understanding.

Functional Theory, the prevailing perspective on the function of counterfactual thinking, posits that the primary purpose of this form of mental simulation is to prepare individuals for the future. However, recent findings have presented challenges to this dominant view. The debate on this topic has recently centered around the possibility that these contradictory results may have arisen from the use of tasks that are inadequate to observe the preparatory function of counterfactuals. Moreover, it has been stressed the importance of considering also more spontaneous (or, at least, more intrinsically motivated) instances of counterfactual thinking when reflecting over its function. In this thesis, Experiments 1 to 3 investigated questions related to the content of counterfactual modifications and their beneficial effects on future performance, utilizing a novel task designed specifically to address previous limitations advanced by the proponents of the Functional Theory. Nonetheless, most of our results did not align with what would have been expected if counterfactual thoughts were produced mainly in a preparatory fashion. Experiments 4 to 6, instead, explored individuals’ inclination to look for non-instrumental counterfactual information, which pertains to information about the outcome of forgone options that does not contribute to improving future outcomes. This type of information seeking, involving the comparison between an actual and a forgone outcome, can represent a proxy of an underlying, genuine process of counterfactual analysis, and thus provides valuable insights for the debate on the function of counterfactual thinking. Indeed, results indicated that individuals readily look for counterfactual information even when it cannot serve any preparatory goal, challenging the notion that the consideration of alternatives to past events is strictly tied to the presence of such goals. These findings, along with prior research, raise questions about the extent to which counterfactual thoughts are produced to prepare for the future, prompting a reevaluation of its underlying functions.

The aim of this thesis deals with the investigation of the cognitive mechanisms underlying the online processing of adverb-verb temporal agreement, namely the coherence in temporal features between the verb and a deictic temporal adverb (e.g. YesterdayPAST I wentPAST/*will goFUT to the jazz concert), during sentence comprehension. There are at least two reasons that make the investigation of this phenomenon interesting and challenging at the same time. The first reason is more theoretical. Differently from well-studied phenomena such as subject-verb agreement or anaphora, the nature of the adverb-verb relation is still debated in theoretical linguistics. The debated nature of the adverb-verb temporal agreement probably relies on the peculiar properties of the constituents involved in the relation. The relation between temporal adverbs and verbs has been traditionally defined anaphoric in nature, since verbs can be bound to temporal antecedents (e.g. adverb) which allow to set a reference time that the event expressed by the verb must refer to. However, other accounts have hypothesized a structural parallelism between the adverb-verb and the subject-verb relation. One question is thus whether this similarities or dissimilarities between subject-verb agreement and temporal agreement at the theoretical level can mirror a similarity/dissimilarity at the cognitive level. The second reason is more empirical and comes from past experimental literature investigating the processing of temporal agreement. Basically, experimental evidence mainly comes from ERPs studies and results are rather sparse and heterogeneous. These ERP studies report an early detection of the temporal violation (around 200 milliseconds after the stimulus onset) but qualitatively different ERP waveforms were elicited by the target word (i.e. the verb) in the different experiments (e.g. LAN, N400, right lateralized negativities). One licit question is thus where the source of heterogeneity resides and how this phenomenon can be better investigated. Given the debated theoretical and experimental past evidence on the processing of this relation, the current work was conducted (i) investigating the pattern elicited by adverb-verb temporal violations compared to other better-studied agreement phenomena, as the one between the subject and the verb, during sentence comprehension (ii) adopting only behavioral techniques since a detailed investigation of the behavioral costs elicited by a temporal violation needs to be established prior to facing the detailed neurophysiological correlates of these processes, which are known to be subject to a larger interpretive freedom with respect to reading time differences. The core of the thesis, namely six empirical studies investigating the processing of temporal violations through different designs and techniques, is preceded by a theoretical chapter which deals with the description of Tense and deictic temporal adverbs from a semantic and syntactic point of view. The main aim of the theoretical chapter is to give a brief overview of the main linguistic theories which have investigated the nature of Tense and temporal adverbs, but also a motivation for considering the syntactic interaction between Tense and temporal adverbs, which is fundamental to preserve the grammaticality of the sentence.The first set of self-paced reading studies, in Italian, addressed two main questions: how different is the processing of adverb-verb temporal agreement with respect to other better-studied phenomena such as subject-verb number agreement? Is the different configuration between the verb and the temporal adverb that has led to heterogeneous results in past experimental literature? In the second (eye-tracking) study, in Spanish, three other questions were addressed: how differently the parser deals with the processing of number, tense and (crucially) person features when encountering a violation on the inflected verb? Does the distance between the two constituents of the dependency play any role in the detection of the violation? Finally, in the third set of eye-tracking studies in English, the processing of the adverb-verb temporal relation was tested in a more complex sentential environment, namely in sentence where the temporal adverb and the verb are separated by an embedded relative clause containing a distracting temporal element. In this set of studies, several questions were addressed: how different can be the processing of adverb-verb temporal agreement at a conspicuous distance? Is the temporal adverb-verb relation sensitive to interference effects from an illicit intervener? How differently this relation behaves with respect to subject-verb agreement and anaphora during memory retrieval? All findings collected in this work provide further evidence for a differentiation in the processing of agreement mechanisms entailing a covariance of features between two constituents within a sentence. This evidence is in line with previous accounts showing a differentiation in the processing of different features (i.e. number, person) within the same relation such as subject-verb agreement (Mancini et al. 2013), and in the processing of the same feature (e.g. number) across different relations such as subject-verb agreement and anaphora (Dillon et al. 2013). This evidence can be particularly relevant for the development of a new model of sentence parsing. In fact, among mainstream models of parsing, only Construal (Frazier & Clifton, 1996) model assumes a relation-sensitive language system. However, a differentiation in the processing of agreement phenomena is not explicitly addressed in terms of feature-related properties. On the other hand, some recent accounts have proposed different processing mechanisms depending on the feature under computation (e.g. Mancini et al., 2013; Carminati, 2005) but a specific formalization of the role of different features properties within a model of parsing has not been provided yet. The second challenge that this current work tried to face was to add more complexity into the agreement configuration testing the adverb-verb agreement relation at different linear distance. The findings here collected seems to give positive evidence on the role played by word order in the processing of the adverb-verb relation, but further investigation needs to address whether other factors may play a role and whether adverb-verb agreement is the only agreement relation which is sensitive to word order. This puzzle thus opens new questions about whether the agreement relation may change even being both the relation and the feature under computation equal. The role played by linear distance in the detection of adverb-verb temporal anomalies also suggests that parsing routines are not “stagnant†, and the language system can deal with redundant information in a very dynamic fashion.

The ability of moving freely in the environment gives us the great advantage to directly interact with it, improving our discriminative abilities. For example, if we were to inspect an object without the chance to actively moving around it, then we could only rely on the information that we can extract from a single point of view with respect of the object. We would have restricted access to the object properties and we would then establish our decisions within those limits. Moving actively allow us to overcome these limitations and gain access to a more complete set of informations regarding the object. This would help us decide what to do next, whether or not to interact with an external object and, in case, providing hints on how to interact. To this extent moving and exploring the environment augment our discrimination abilities. Moreover, active movements help us to form a complete sense of space.

One of the core human abilities is that of interpreting symbols. Prompted with a perceptual stimulus devoid of any intrinsic meaning, such as a written word, our brain can access a complex multidimensional representation, called semantic representation, which corresponds to its meaning. Notwithstanding decades of neuropsychological and neuroimaging work on the cognitive and neural substrate of semantic representations, many questions are left unanswered. The research in this dissertation attempts to unravel one of them: are the neural substrates of different components of concrete word meaning dissociated? In the first part, I review the different theoretical positions and empirical findings on the cognitive and neural correlates of semantic representations. I highlight how recent methodological advances, namely the introduction of multivariate methods for the analysis of distributed patterns of brain activity, broaden the set of hypotheses that can be empirically tested. In particular, they allow the exploration of the representational geometries of different brain areas, which is instrumental to the understanding of where and when the various dimensions of the semantic space are activated in the brain. Crucially, I propose an operational distinction between motor-perceptual dimensions (i.e., those attributes of the objects referred to by the words that are perceived through the senses) and conceptual ones (i.e., the information that is built via a complex integration of multiple perceptual features). In the second part, I present the results of the studies I conducted in order to investigate the automaticity of retrieval, topographical organization, and temporal dynamics of motor-perceptual and conceptual dimensions of word meaning. First, I show how the representational spaces retrieved with different behavioral and corpora-based methods (i.e., Semantic Distance Judgment, Semantic Feature Listing, WordNet) appear to be highly correlated and overall consistent within and across subjects. Second, I present the results of four priming experiments suggesting that perceptual dimensions of word meaning (such as implied real world size and sound) are recovered in an automatic but task-dependent way during reading. Third, thanks to a functional magnetic resonance imaging experiment, I show a representational shift along the ventral visual path: from perceptual features, preferentially encoded in primary visual areas, to conceptual ones, preferentially encoded in mid and anterior temporal areas. This result indicates that complementary dimensions of the semantic space are encoded in a distributed yet partially dissociated way across the cortex. Fourth, by means of a study conducted with magnetoencephalography, I present evidence of an early (around 200 ms after stimulus onset) simultaneous access to both motor-perceptual and conceptual dimensions of the semantic space thanks to different aspects of the signal: inter-trial phase coherence appears to be key for the encoding of perceptual while spectral power changes appear to support encoding of conceptual dimensions. These observations suggest that the neural substrates of different components of symbol meaning can be dissociated in terms of localization and of the feature of the signal encoding them, while sharing a similar temporal evolution.

From the methodological perspective, we validated the use of a recently introduced multivariate searchlight pattern classification method for the analysis of training effects in language studies. We found that, compared to the standard GLM method, the searchlight analysis has comparable and, in some cases, greater sensitivity in localizing BOLD signal changes, and thus it represents a promising complementary tool in studies of training. "

Growing up as bilingual seem to exert some positive and negative effects on general cognitive functioning. Positive gains concern a earlier maturation of the attentional system in childhood and its later decline in adulthood. Bilinguals have been shown to be advantaged , compared to their monolingual peers in tasks requiring control of attention: they are more accurate in judging the grammaticality of sentences (Bialystok et al.1986); faster in the Attentional Network Test and in the Simon task (Costa et al 2007; Bialystok et al.2005).On the other hand bilinguals are disadvantaged in t asks requiring speech production : they are slower in acceding to the lexical representation of words (Ivanova, Costa,2007); they exhibit more tip of the tonguge states (Gollan & Silvenberg, 2001) and they show lower rates in retrieving verbal stimuli (Gollan,2002).If bilingualism can exert these influence sin boosting and hampering these so general cognitive functions, bilinguals children might also show these effects across domains.We surveyed the presence of these advantages and disadvantages in a domain so relevant as it is speaking two languages that is the number field. Bilinguals and monolinguals children were asked to perform three different number tasks: number Stroop, verification and dot counting.Unlike in the study of Bialystok et al. (2004; 2005) who employed a classical Stroop task, no difference was found between mono- and bilinguals as for the number Stroop effect. In the verification task, an associative confusion effect was found in the bilingual but not in the monolingual group. Finally, when children were asked to count, bilinguals performed equally well as their monolingual peers in counting items in the subitizing range only, whereas they were slower than their peers when they counted from 4 to 9 dots. This latter result, in particular, is consistent with many psycholinguistic studies claiming that bilinguals are disadvantaged in tasks requiring lexical access (Costa & Caramazza, 1999), and extend them to the number processing domain.

Object manipulation is central to our daily interactions with the environment. Failing to select, prepare or perform correct prehension movements results in dramatic limitations for the affected individual. Whereas we begin to have a better understanding of the neural mechanisms underlying the execution of object-directed movements, less is known about how exactly our brain makes the plan for action. Previous studies examining movement planning suggested that neuronal populations in parieto-frontal areas contain information about upcoming movements moments before they actually take place. However, such studies typically used experiments in which the participant was instructed about the movement to plan with visual or auditory cues, making it difficult to disentangle movement planning from the processing of cues and stimulus- response (S-R) mapping. In our first functional magnetic resonance imaging (fMRI) study (Study I), we compared an instructed condition with a free-choice condition that allowed participants to select which prehension movement to perform: a condition in which the task was not tied to specific external cues (i.e., no direct S-R mapping). Using multi-variate pattern analysis (MVPA), we found contralateral parietal and frontal regions containing abstract representations of planned movements that generalize across the way these movements were generated (internally vs externally). The majority of previous studies were based on delayed-movement tasks, which introduce brain responses unrelated to movement preparation. Consequently, whether these findings would generalize to immediate movements remained unclear. In our second fMRI study (Study II), we directly compared delayed and immediate reaching and grasping movements. Using time-resolved MVPA allowed us to reveal shared representations for delayed and non-delayed movement planning in human primary motor cortex and examine how movement representations unfolded throughout the different stages of planning and execution. Overall, our findings expand previous understanding of the regions implicated in movement planning and offer new insights into the dynamics of the human prehension system.

Among numerical formats available to express probability, ratios (i.e., frequencies) are extensively employed in risk communication, due perhaps to an intuitive sense of their clarity and simplicity. The present thesis was designed to investigate how the use of superficially different but mathematically equivalent ratio formats affects the magnitude perception of the probability that is conveyed. In particular, focus of research was the influence that those expressions, when employed in risk communication of prenatal screening test results, have on prospective parents’ perceptions of the chance of having a Down syndrome-affected child. No clear evidence was found in the literature, on whether the choice of one of the equivalent ratio format that can be used to state a given probability does matter in terms of subjective perception of the chance. Indeed, existent studies deliver contrasting results, and theories elaborated on those basis point in diverging directions. These could be summarised in the suggestion, on the one hand, that people tend to neglect denominators in ratios (hence they judge 10 in 100 as larger than 1 in 10: “Ratio-bias” or “denominator neglect”) and, on the other hand, in a claim that people neglect numerators, rather than denominators (hence they rate 1 in 10 as larger than 10 in 100: “group-diffusion” or “reference group” effect). Nevertheless, implications of either group of theories could not entirely be transferred to the specific issue at study, mainly because of problems of ecological validity (type of scenario and stimuli, experimental design). Hence, provided the necessary adjustments to both the original experimental designs and materials, we tested empirically the applicability of those predictions to the specific case under examination. Subjective evaluations of equivalent ratios presented between-subjects in scenario paradigm were analysed by means of the magnitude assessments given by a total number of 1673 participants on Likert scales. Overall, results of a series of 12 main studies pointed to a new bias which we dubbed the “1 in X effect” given the triangulation of its source to that specific ratio format. Indeed, findings indicated, that laypeople’ subjective estimation of the same probability presented through a “1 in X” format (e.g., 1 in 200) and an “N in X*N” format (e.g., 5 in 1000) varied significantly and in a consistent way. In particular, a given probability was systematically perceived as bigger and more alarming when expressed in the first rather than in second format, an effect clearly inconsistent with the idea of denominator neglect. This effect was replicated across different populations and probability magnitudes. Practical implications of these findings for health communication have been addressed in a dedicated section, all the more necessary considering that in one study on health-care professionals we had found, that they appeared themselves de-sensitized to the “1 in X effect” (seemingly because of their daily use of probabilistic ratios). While the effect was not attenuated in laypeople by a classic communicative intervention (i.e., a verbal analogy), it disappeared with one of the most employed visual aids, namely an icon array. Furthermore, in a first attempt to pinpoint the cognitive processes responsible for the bias, the affective account stemming from literature on dual-process theories has not received support, contrary to our expectations. Hence, the most likely origin for the bias seems to reside either, as suggested by some inspections, in a specific motivation to process the information, and/or in the increased ability to see oneself or others as that affected when a “1 in X” format is processed. Clearly, further empirical research is needed in order to attain this cognitive level of explanation.