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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

The smell of altruism: Incidental pleasant odors and chemosignal as prosocial decisions moderators

Perrotta, Valentina January 2012 (has links)
The study of the interactions between olfaction and the decision making processes has mainly focused on the investigation of what is considered the most useful odor to disperse in the air to drive the consumers' choices to prefer a product rather than another one. Despite the fact that some studies showed the existence of associations between odors and prosocial behavior, much less data are available on the links between olfaction and donation in favor of public goods. Thus, the main purpose of the series of experiments described in this thesis is precisely that to shed some light on the investigation of the nature of pleasant odor-decision and on the chemosignal-decision associations. In order to achieve this, the presence of an odor and the congruence between odor and decision task has been manipulated, and the decision to donate has been tested in different domains. Therefore, in the first series of experiments, we manipulated the presence of an ambient pleasant odor, expecting that the congruent stimuli sharing the more stable association odor-concept, would have resulted in an overall increase in the WTC (willingness to contribute) and WTP (willingness to pay) in the decision to donate in favor of a public good. The results confirmed the existence of an association between the olfactory stimulus congruence and the amount donated in favor of a public good. Interestingly, this effect is confirmed in both hypothetical and real decision settings. Moreover, the stimulus modality was manipulated presenting congruent olfactory or visual stimuli. Our findings confirmed the preferential link between olfaction and cognitive processes and showed higher donations in the olfactory setting (compared to the visual one). The existence of associations between odors and words are examined to know if the odors could semantically drive cognitive processes different from decision making. The results confirmed the existence of an association between the olfactory stimulus pleasantness and the performance in a lexical decision task (LDT). Thus, this effect is mediated by the presence of a pleasant odor and not by the semantic congruence between odor and the presented words. Moreover, the visual modality tend to worsen the LDT performance even if the visual stimulus was semantically congruent with the word presented. Finally, even though the semantic link appears to be crucial for cognitive processes such as decision, it seems not so important for memory and linguistic processes involved in the LDT. The second series of studies involved the presence of chemosignal, expecting that the congruity between stimulus and decision (the chemosignal used is AND, known as the best candidate to be considered a human chemosignal) would have resulted in an overall increase in amount of money donate to unknown persons during Dictator and Trust Game. The results confirmed the existence of an association between the chemosignal stimulus presence (and its olfactory experience) and the amount donated, and a mediation effect due to the positive mood (in presence of AND) especially in females and with high AND concentration.
32

The Arousing Risk: Influences of positive and negative arousal on preferences for economic risk

Galentino, Andrea January 2015 (has links)
Standard economic models explain decision making under risk as a utility maximization process. Developments in cognitive psychology and neuroeconomics showed the volatility of such conceptualization highlighting human bounded rationality and discussing the role of decision maker’s affective state (basic reactions to any emotionally charged event) in cognitive evaluation of risk (risk as feeling). In particular, an affective-based evaluation of choice options may determine whether decision maker’s behavior will be risk averse or risk seeking. Evidence indicates that affective reactions carry over significant information about the goodness of certain choice options directly influencing risk taking behavior. Affective influences on decisions may be directly associated with the evaluation of the choice options and the anticipation of future outcomes (integral affect) or may be associated with stimuli or event unrelated to the decision at hand, for example contextual factors or environmental cues (incidental affect). A classic advertisement strategy, such as a smiling face presented in association with a good, is an example of contextual affective manipulation. Research shows that experiencing a positive affective state may lead to risk aversion behavior while negative affect may lead to risk seeking. However, previous studies mostly adopted a valence-based approach to the study of affect ignoring its multidimensional nature. In particular, the role of arousal has been largely neglected. Recent studies showed that emotional states with the same valence may have opposite consequences on risk taking. Therefore, the main purpose of the series of studies described in this dissertation was to investigate the effect of inducing incidental affective states at high and low levels of negative arousal or positive arousal on preferences for monetary options varying in risk. Research shows that elevated arousal is associated with cognitive depletion, increased sensitivity to rewards, immediate gratification, less resistance to temptation. Therefore, we hypothesized that affective states characterized by high levels of arousal might increase preferences for the riskier option. We further predicted that including arousing stimuli as contextual factor of a decision scenario would capture individual attention interfering with information processing of risk. In order to achieve this goal, in a first series of experiments we asked participants to make choices between couples of two-outcomes lotteries with the same expected value but different risk. Arousal was manipulated by presenting participants with visual stimuli (IAPS pictures) varying in the level of arousal (high or low) keeping the valence unvaried (negative or positive). By adopting the technique of contextual priming, participants were simultaneously exposed to stimuli (the lotteries) and the contextual factor (the arousing/unarousing image). An effect of arousal on predicting risky choice was found. Probability of selecting the riskier lottery was higher when an arousing stimuli (unpleasant or pleasant) was included as part of the decision context. In some cases, positive arousal was found to interact with gender: risk taking was higher in males than females when a pleasant arousing cue was presented. In a second series of studies, participants performed the same task and, by using an eye tracker, eye fixations and looking times were recorded. The predicted effect of arousal on attention was found. Participants spent more time looking at the arousing image (unpleasant or pleasant). This result is in line with arousal theories which correlate the level of arousal to attention allocated to the arousing stimuli. Furthermore, participants seemed to process less risky information (as indicated by decreased looking times toward the riskier option) when the arousing stimuli was contextually presented, as opposed to when the unarousing stimuli was presented.
33

The effects of counterfactual comparison on learning and reasoning

Timberlake, Benjamin January 2019 (has links)
How humans make choices in uncertain and competitive situations is a key determinant of viability and successful living. Improving those choices requires sometimes encountering undesirable outcomes and avoiding them, eventually even anticipating them in novel situations. Learning depends on making choices, encountering errors and updating evaluations of options. Various models extended from the reinforcement learning framework compared to human behavior describe in part how individuals heterogeneously make choices. To peer into the components of these mechanisms, strategic games that emulate real-world situations provide measurable and manageable environments in which to examine slight differences in choice behavior among different people. Such differences may be endogenous to participants (e.g. age or learning disposition) while others derive from external events (e.g. emotional induction or brain stimulation). We contrasted such behavior in three situations involving learning or competition, leveraging differences in age, emotional induction and brain stimulation. We aimed to describe the variations in choice behavior across these differences and investigated, when possible, how prior conditions generated a transfer of learning from one domain to another. The work here builds on recent investigations of neural mechanisms underlying choice behavior during strategic or competitive interaction.
34

Shape-to-color associations in non-synesthetes: perceptual, emotional, and cognitive aspects

Malfatti, Michela January 2014 (has links)
The study of cross-modal and cross-dimensional associations in non-synesthetes has become an increasingly hot topic in recent times (see Spence, 2011, for a review). Despite the many examples of associations between shape/color-stimuli on one hand and stimuli of different sensory nature on the other hand, little is known about the way shape and color are interrelated with each other. The purpose of our research was to test whether non-synesthetes also exhibit systematic associations between these two different dimensions of the visual domain, that is, shape and color. Furthermore, our study also relates to art, and in particular to Kandinsky’s theory on shape-color correspondences (1912, 1926), which could be tested indirectly. The project consisted of six experiments, some of them (Experiments 1-3 and 6) carried out in the Experimental Psychology Labs at the University of Trento under the supervision of Prof. Liliana Albertazzi, and the others (Experiments 4-5) carried out in the Visual Perception and Aesthetics Lab at the University of California Berkeley, under the supervision of Prof. Stephen E. Palmer. Experiment 1 provided the first evidence that people tend to match certain hues to certain simple geometric shapes. The strongest relations were found between the triangle and yellows, and the circle and square with reds, confirming only in part Kandinsky’s artistic findings. Experiment 2 replicated the results of Experiment 1 with a different group of participants and showed that the pattern of shape-color associations that previously emerged was independent of a shape’s size, area/perimeter, and stability. Experiment 3 examined the relation between parts of shapes (angles) and hues, also in order to assess if the choice of a hue to be matched with a given shape could be partly driven by its angles. In the remaining experiments (4-5), we extended the previous studies to color dimensions other than the hue, and to an even wider variety of shapes and shape-features. The shape-features studied included pointedness, intersections, symmetry-axes, concavities, and the number of generating-points. We found that specific shape-features of line-shapes (Experiment 4) or closed geometric shapes (Experiment 5) influence specific color attributes (saturation, lightness, redness/greenness, and yellowness/blueness) of the associated colors. Our results also suggested that shape-color associations may be mediated, in part, by emotions; indeed people tend to match colors and shapes that have similar emotional associations (e.g., angry colors are matched to angry shapes). Finally, Experiment 6 assessed in an exploratory way the association between words related to abstract concepts and hues. Altogether, additional examples of associations in the non-synesthetic population were reported. We suggest that this new trend of research, at large, could improve the study of human perception and cognition, guide the search for neural correlates, as well as find possible applications in a variety of disciplines, including ergonomics, art, and design.
35

A study on the representation of the arithmetic facts memory: cognitively speaking, is the commutativity a property of multiplications and additions?

Didino, Daniele January 2011 (has links)
In this thesis we deal with the role of the commutative property in the organization of the memory that encodes the knowledge about two arithmetic operations: multiplication and addition. Despite its relevance in arithmetic the commutative property has been largely neglected. This theoretical underestimation of the order of the operands and of the cognitive processing of commutative property is likely due to the lack of strong empirical evidences. In this thesis we provide new and clear empirical evidences of a operands-order effects. Five experiments were conducted by using various methodologies. Our results indicate that commutative pairs are processed differently for the two operations. For additions, we found an effect of the order of the operands. Namely, the problems in which the first operand is the larger (e.g., 7+4) were solved faster than the commuted problems (e.g., 4+7). For multiplication, we found an extremely surprising result that can not be predicted by any of the current models of arithmetical cognition, that is an interaction between the order of the operands and the size of the problem. Namely, for large multiplications (both operands larger than 5) the problems in which the first operand is the smaller (e.g., 7×8) were solved faster than the commuted problems (e.g., 8×7); for small multiplications (both operands smaller than 5) and medium multiplications (one operand smaller and the other larger than 5) the problems in which the first operands is the larger (e.g., 3×4, 7×3) were solved faster than the commuted problems (e.g., 4×3, 3×7). For both operations the relevant role of the order of the operands (and its interaction with size for multiplication) in the processing of the problems is also confirmed by a ERPs study. This results are interpreted as the evidence that the arithmetic facts memory is organized by the commutative property. More precisely, we propose to interpret the effects we found as due to the interaction of two factors that shape this memory according to the commutativity: (1) the order of acquisition of the commuted pairs and (2) a reorganization of the memory due to the use of non-retrieval procedures that privilege one of the two orders of the operands. Clearly, further researches are needed in order to better understand the relation between arithmetic facts memory and the commutative property. However, our result have showed a new effect that can usefully be used to investigate how the cognitive system encode, represent and process the arithmetical knowledge.
36

Constructing multiple objects across space and time

Muschter, Evelyn January 2018 (has links)
For us to interact with our environment we must have an understanding of the location and properties of the objects within it over time. Incoming stimuli from different sensory modalities continuously provide information. In order to create a coherent percept, it is necessary to combine these sensory signals in the brain into a single representation of an object or event. Temporal integration, the process of combining information over time is one important prerequisite for it. Likewise, multisensory integration, the process of combining information from different sensory modalities to generate a coherent percept is of great importance. Furthermore, as our environment is not static but dynamic it is necessary to combine sensory information over time and space. Despite, the ever-increasing neuroscientific results, much about the underlying brain mechanisms remains unknown. This thesis describes an effort of understanding how sensory information are integrated in the brain and what effects attention has on how we integrate multiple objects in space and time. Chapter 1 introduces the reader to the existing literature on neural oscillations, specifically alpha band frequency, which is hypothesized to play a critical role in temporal processing and attention. This is followed by a review of the literature on temporal integration and the theoretical background of multisensory integration. The following chapters will report the three studies conducted: Chapter 2 describes the first study, a MEG study that investigates the role of alpha oscillations in temporal integration. Chapter 3 reports the second MEG study, which focuses the role of attention to modality in multisensory integration. Chapter 4 presents the third study, a behavioral oscillations study, which focuses on the role of neural oscillations in selective attention in a dynamic scene. Finally, Chapter 5 summarizes all the findings from this research.
37

Audiotactile interactions: psychophysical and neuroimaging approaches

Leonardelli, Elisa January 2015 (has links)
In daily life, we are immersed in a continuous flow of stimuli targeting each of our different senses. Far from being independently processed, accumulating evidence has been widely documented by studies showing that stimuli from different modalities largely interact. However, despite the increasing interest, the interpretations of the results of experiments studying multisensory interaction are still controversial and the underlying mechanisms remain broadly unknown. The aim of this thesis is to investigate the interactions that occur between the senses of audition and touch. Audiotactile interactions have been far less studied than the ones existing between other modality pairings. Maybe because they go often unnoticed though being well present in many everyday life situations. This thesis focuses mainly on two aspects that concern interactions: understanding the impact of the relative saliency between the stimuli and investigating the mechanism behind perceptual integration. These questions are addressed respectively in two studies conducted by means of magnetoencephalography. The thesis is structured as following: in chapter 1, I provide the theoretical background to my scientific questions. A brief synthesis of the two main studies is presented in chapter 2. The two studies are entirely reported under the form of manuscripts in chapter 4. Finally, in appendix a behavioral study that investigates spatial aspects of AT interactions is reported. Although the results of this study are of pertinence of the project, given the preparatory character and the preliminary state of the study we decided to show them in the appendix rather than include them in the main body of the thesis.
38

Does the Way we interact with Technology Affect Cognitive Performance? An in-depth analysis of writing devices

Cerni, Tania January 2014 (has links)
The great influence of mass technologies has changed our writing modality that is moving from the traditional use of pen and paper to the domain of keyboards and recently to touchscreen tools, both in everyday life and in educational contexts. The digitalization of writing and of the texts we write, but also the ubiquity of digital technologies, should encourage a deeper understanding of the implications of the physical and sensorimotor changes in writing. It is reasonable to think that the motor-perceptual differences between different writing modalities can lead to different cognitive performances in linguistic tasks, depending on the writing movement that has to be performed but also on the experience that we have with this movement. In this work, I take into account the role of tangible devices for writing and their different haptic affordance, rarely considered in the study of language, in general, and of writing, in particular. To do so I analyzed different behaviors while we use different writing technologies and discuss the findings from a cognitive science point of view. The general aims of this thesis consists in establishing possible cognitive entailment of different types of writing modalities, in explicating their role in other linguistic tasks and in evaluating the possible implication on daily life and education. The thesis is presented like a collection of papers, results of my research activity and experiences during my participation in the doctoral school. I divided my work in three separate chapters in which different research points of views are analyzed, different experimental procedures are used and different technological devices for writing are tested. Chapter 1 present a study aimed at investigating whether technologically mediated linguistic performance reflects cross-modal interaction and whether it is modulated by the writing technology used, specifically a touchscreen and a keyboard. Chapter 2 comprises a set of studies dedicated to investigate whether it is possible that a strong experience in typing influences our linguistic abilities. Furthermore, typing and mobile typing are compared testing if the two writing modalities share the same motor behaviors. Mobile technologies are also the argument of Chapter 3 in which I present two theoretical papers dedicated to the potential of these devices for learning, in general, and for second language learning, in particular.
39

Assessing audiotactile interactions: Spatiotemporal factors and role of visual experience

Occelli, Valeria January 2009 (has links)
This thesis investigated the crossmodal interactions occurring between hearing and touch. Chapters 1 to 6 present the background to this topic and an introduction to the underlying mechanisms of crossmodal perception. Chapter 1 provides a historical overview on the pioneering studies in this issue, whereas in the successive ones the main behavioural evidence on is described. Specific aspects are presented across the chapters, with Chapter 2 presenting the studies using detection/discrimination tasks, intensity tasks, or investigating texture perception or crossmodal sensory illusions and pseudosynaesthetic correspondences. In the subsequent chapters, more specific aspects are taken into consideration, such as the temporal (Chapter 3) and the spatial (Chapter 4) constraints characterizing audiotactile interactions. In Chapter 5, special attention is given to the neural substrates of the audiotactile sensory interplay, in both humans and monkeys. Since there is considerable evidence showing that visual deprivation influences how touch and hearing interact, Chapter 6 will be devoted to explore this topic in more detail. The following chapters present the experimental studies designed to empirically investigate different aspects of audiotactile interactions. Chapter 7 contains experimental studies examining the potential existence of a sensory dominance between hearing and touch, by investigating different portions of the peripersonal space and/or spatial arrangement of the stimuli. Chapter 8 is focused on evaluate the capability of humans in matching the frequency pattern of auditory, tactile and crossmodal stimuli. The spatial factors affecting audiotactile interactions will be explored in Chapter 9, by evaluating how the perception of apparent motion in one modality is biased by the presentation of apparent moving stream in the other modality. The investigation of crossmodal compatibility effects is the topic of Chapter 10. Since visual deprivation has been proved to influence how touch and hearing interact, the last chapter (Chapter 11) will be devoted to compare either spatial or temporal perception, as well as the construction of frames of reference for tactile processing - in relation with auditory stimulation- in blind and sighted individuals.
40

Sulle determinanti della fallacia della congiunzione: Test dell'ipotesi basata sulla teoria della conferma bayesiana

Russo, Selena January 2010 (has links)
All'interno dell'annoso dibattito sulla razionalità del ragionamento umano il fenomeno della fallacia della congiunzione (CF) riveste un ruolo di estremo interesse (Tversky & Kahneman, 1983). La CF rappresenta una particolare tipologia di errore logico e probabilistico ed è uno dei fenomeni maggiormente studiati nell'ambito del ragionamento probabilistico. Essa consiste nel valutare come maggiormente probabile l'occorrenza della congiunzione di due eventi (h1&h2) rispetto alla probabilità di presentazione di uno dei due costituenti (h2), giudizio che contravviene ai dettami normativi della regola di congiunzione. Nel Capitolo 1 verrà presentato il problema della fallacia della congiunzione e la sua rilevanza per la spiegazione del ragionamento umano. Nel Capitolo 2 verranno presente le principali proposte esplicative analizzandone i maggiori punti di forza e le limitazioni, in particolare per quanto riguarda la loro forza predittiva. Nonostante i numerosi tentativi di spiegazione, a tutt'oggi difettiamo di una teoria esaustiva in grado di predire l'occorrere del fenomeno. Tra le spiegazioni avanzate particolare rilevanza ai fini della nostra indagine assumono l'insieme della Averaging Rule Hypotheses, che assumono che la CF sia il risultato di una valutazione della probabilità di una congiunzione effettuata attraverso regole non normative del calcolo della media applicate alle probabilità dei congiunti (Nilsson, 2008). Una più recente interpretazione, la Random Variation Hypothesis, descrive invece la CF come l'effetto di un errore casuale insito nel processo valutativo (Costello, 2009). Entrambe queste teorie descrivono e prevedono l'incidenza della CF come funzione della probabilità degli eventi componenti la congiunzione, in particolare l'incidenza dell'errore aumenterà all'aumentare della probabilità assegnata al congiunto aggiunto h2. Queste teorie forniranno il termine di paragone contro cui confrontare il valore esplicativo e predittivo dell'ipotesi che presenteremo nel capitolo successivo. Nel Capitolo 3 si avanzerà una nuova lettura del fenomeno, proposta inizialmente da Crupi, Fitelson & Tentori, 2008 e basata sulla teoria bayesiana della conferma, per cui si ipotizza che le stime probabilistiche erronee tipiche della CF siano in realtà connesse con valutazioni sulla relazione di conferma, intesa come l'apporto informativo che una evidenza conferisce ad una ipotesi. Più in dettaglio, in accordo con questa analisi l'incidenza dell'errore della congiunzione è descritto come funzione dell'aumento del supporto fornito all'ipotesi aggiunta h2. La parte più prettamente sperimentale del presente lavoro è contenuta nel Capitolo 4 dove verranno presentati quattro studi sperimentali finalizzati ad una maggiore comprensione del fenomeno della fallacia della congiunzione, in particolare confrontando empiricamente la spiegazione basata sulla nozione di conferma induttiva con le principali teorie alternative. Il termine di confronto privilegiato sarà fornito dall'insieme delle Averaging Hypotheses e dalla Random variation hypothesis: questi due approcci esplicativi presentano infatti forti similitudini, per quanto concerne le predizioni, con la teoria basata sulla nozione di conferma bayesiana, in quanto grado di conferma e grado di probabilità sono strettamente correlati e spesso mutano in maniera congiunta. Per dimostrare la validità della nozione basata sulla conferma occorre quindi separare le responsabilità dei due fattori, e quindi creare contesti sperimentali in cui le due teorie forniscono predizioni divergenti. I risultati mostrano che la proposta teorica basata sulla conferma si dimostra un buon predittore del verificarsi del fenomeno. In conclusione questi risultati verranno ripresi in considerazione dal punto di vista teorico, per saggiarne la rilevanza nei confronti della ricerca empirica sulla CF, per tentare di gettare una luce sul ruolo della CF stessa nel quadro dell'indagine sulla natura del ragionamento e per suggerire nuovi percorsi di riflessione.

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