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Browsing by discipline "Kognitiotiede"

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  • Hanski, Atte (2016)
    Aims The goal of this paper is to examine the peripheral factors of stimuli in Samuel Tuhkanen's pro gradu thesis experiment and evaluate the possibility of improving the experiment by manipulating the peripheral factors. Methods The peripheral factors of stimuli in Tuhkanen's experiment have been explored in light of earlier literature on peripheral vision. The different factors have been evaluated on how they affect the results of the experiment as well as how the experiment could be changed depending on these factors. Results and conclusions Motion, salience, color, shape, brightness, crowding and placement factors were identified as irrelevant because they are constant in the experiment. Size, complexity, contrast and orientation were identified as being useful for manipulating the results of the experiment. Of these factors size and contrast were found the best ways of manipulating the difficulty of the experiment.
  • Savisaari, Olli (2016)
    Human perception is seriously limited in relation to the countless stimuli of one’s surroundings. It is guided by attention, which can be directed only at a fraction of all available stimuli at a given moment. The topic of this thesis is a phenomenon illustrating the constrained nature of attention called the attentional blink. One of the goals is to consider the origin and mechanisms behind the phenomenon as well as the current applications of 1) the phenomenon itself and 2) the methods used in attentional blink research. The attentional blink occurs in a rapid succession of stimuli, which unveils the limits of temporal capacity of attention. As a consequence of the blink, some of the target stimuli do not reach conscious processing. The phenomenon has sparked wide interest since the 1980’s, but the mechanisms, operating principle and especially the neural correlates of attentional blink are still under debate, which makes the topic relevant even today. Attentional blink is most commonly studied with the rapid serial visual presentation –method (RSVP). This method, however, can be applied to many more contexts as well, some of which are addressed here. The thesis is a review covering 32 articles and publications of the attentional blink or topics directly related to it. They include only reports of studies done on healthy individuals and reviews of such experiments. Although there is much more literature on the topic besides the ones chosen here, these 32 provide a critical, yet comprehensive review of an attentional limit called the attentional blink. Attentional blink is commonly known as a consistent and universally occurring phenomenon, during which attentional resources are temporarily suppressed. According to most theories it occurs due to choosing specific target items to be processed in working memory, though contradicting evidence exists. Somewhat surprisingly, there are individual differences in the duration and magnitude of the blink, which are affected by the processing speed of working memory and the ability to update its contents. Thus the blink does not appear exactly the same way for everyone. Actual applications of the blink seem to be very few in number, possibly due to limited benefits of application or the specificity of the phenomenon. The RSVP-method used in attentional blink research is more widely applied in modern technology, for example in text presentation. For any application to be useful, it needs to reduce the overload on attentional and working memory systems in order to heighten perception. However, to be able to utilize attentional blink and RSVP maximally, more research is needed.
  • Väätäjä, Sara (2016)
    This Bachelor’s Thesis covers the IDyOM (Information Dynamics of Music) model, which models the prediction of melody, and is based on statistical learning of melodic regularities. In addition the model is contrasted with the earlier Implication-Realization theory (IR theory) of the prediction of melody. The IR-theory hypothesizes that the prediction of melody is composed of innate bottom-up rules and learned top-down style. First some music theoretical concepts and theories and models of prediction are discussed. Melody is an essential part of music at least in Western culture. Melody can be defined as a sequence of tones. The prediction of melody can be studied with formal models, in this case a cognitive model. Predictive cognitive processes allow an organism or artificial intelligence to make a model of its future state and direct its behaviour accordingly. This Thesis also presents the background theories of statistical learning and information theory. The IDyOM model simulates statistical learning which means finding and learning regularities from input, by using unsupervised learning, in which correct answers are not taught to the model. The model is based on Shannon’s information theory which postulates regularities of discrete sources and stochastic processes. The IDyOM model is multidimensional in two ways: it combines the dimensions of the input, e.g. pitch, into new dimensions, e.g. intervals, and uses two inputs to compare a new melody to a broader corpus. The performance of the IDyOM model is compared to behavioral studies with human subjects and the IR theory. The IDyOM model explains human prediction of melody at least as well as a computational implementation of the IR theory. Statistical learning may be a mechanism for learning melodies.
  • Sarasjärvi, Kiira (2016)
    In my review (bachelor thesis) I am presenting J.N. Vickers theory about Quiet eye. In the beginning I am go through how we use eye fixations in a everyday life. According to stuides people are pointing their eyes only for targets which re relevant for the upcoming task. At the same time the amount of fixations are strived to keep low. Vision has shown also to lead usually in action after two second after the eye fixation. The Quiet eye is the final fixation or tracking gaze on a location or object that is within 3ᵒ of visual angle for a minimum of 100ms. Quiet eye is mainly studied and has still be used in sport science. The most used research frame is to study difference in eye fixations periods and location between experts and novisers, success and unsuccess sportperformaning and before and after quiet eye training. In my review I also present fractioned reaction time paradigm and internal model. I try to create an overall picture about how and why The Quiet eye theory could actually worked and how the models could explain the differences between the different study groups. My goal is to give to the reader a general view about the quiet eye, the theories and literature behind it.
  • Räsänen, Mari (2016)
    In this thesis I review the research literature about possible connections between the perception of speech prosody and music. First I present some studies regarding the perception of speech prosody and second, about music perception in general. In the first sections I focus mainly on relatively early perceptive processing, connections between perception and the motor system, and perception of emotions in speech and music. Speech prosody as a term refers to the music-like features of speech, such as pitch, loudness and tempo. The prosodic features of language can have emotional as well as linguistic content. This is why in prosody literature the phenomenon is often divided into linguistic prosody and affective or emotional prosody. Because of emotional prosody, it is possible to recognize different emotions from speech signal. Linguistic prosody refers to the role of speech prosody in speech segmentation and clause categorization. In the brain, prosodic features are processed ventrally in the right auditory cortex and frontal cortex. The motor system also contributes to the perception and production of prosody, especially in emotional prosody. Like prosody, music has melodic and rhythmic features that are in part processed separately in the brain. Both pitch and rhythm are processed first in the right auditory cortex. The motor system is also involved in the perception of rhythm and emotion. Consequently, the perception of music and prosody seems to overlap in some parts of the brain. Evidence for overlapping processes can also be seen in transfer effects from music to prosody perception, which seems to improve with musical training. Also problems in music perception in amusia or schizophrenia appear to be related to deficits in perception of prosody. There seems to be several connections between prosody and music perception, possibly related to similar processing of melodic and temporal features. The connection between language and music has traditionally been attributed to similar syntactic structures, but prosody could also be a convincing option. However, more research on this topic is needed.
  • Turkkila, Roosa (2016)
    The classical views of Cognitive Science has been challenged by the embodied view of cognition. It rejects traditional views that cognition is computation on amodal symbols in a modular system, independent of the brain’s modal systems for perception and action. Instead it proposes that sensory and motor processes and bodily states underlie cognition. Especially the results in semantic processing has been seen as a clear evidence for embodied cognition. Studies have constantly demonstrated that motor processes are activated during the semantic processing and that stimulating these areas leads to changes in semantic processing. However, there are also results that are inconsistent with the strongest versions of embodiment. There are large parts in the brain far from sensory and motor areas taking part in semantic processing. The theories of secondary embodiment have seen this as a prof for amodal system in semantic processing. However, the relation between action and semantics is not yet fully understood and it could be that partly the same neural systems that contribute to the understanding of action also underlie general semantic processing.
  • Alafuzoff, Aleksander (2016)
    The terms brain signals and brain activity are widely used in cognitive neuroscience. These terms are used to refer to both the signals produced by the methods used in neuroscience as well as the signals produced by the brain for its own purposes. This dichotomy can be made apparent by making a conceptual distinction between signals from the brain, produced in neuroscientific research, and signals in the brain, used by neurons to communicate. Understanding the relationship between the signals being recorded and the signals used by the brain is crucial for interpreting the results and conclusions of cognitive neuroscience research. Signals in the brain can be divided into three groups: synaptic, ephaptic, and diffusive. These groups can be characterized by the mechanism by which the signals propagate, the speed, range, and selectivity of the signals, as well as the number of unique signals that can be sent in each. Similarly, signals from the brain can be divided into three groups, according to the physical phenomenon being measured: electrophysiological, blood-flow dependent, and optical signals. These signals and methods that produce them can be distinguished in terms of their recording region, spatial summation, time resolution and invasiveness. Modern methods in neuroscience do not measure all or even the most significant signals in the brain. In particular, no non-invasive method is capable of discerning the activity of single neurons or microcircuits. If the mechanisms underlying cognitive processes are on the cellular level, one of the central challenges of cognitive neuroscience is and will be to resolve the incommensurability between signals recorded from and signals used by the brain.
  • Pölönen, Pasi (2016)
    Tavoitteet. Kirjoitelman tavoitteena oli luoda katsaus somaattisten merkkitilojen hypoteesiin: hypoteesin neuraalisiin mekanismeihin, hypoteesia tukeviin tutkimustuloksiin, siihen kohdistuneeseen kritiikkiin ja kritiikin vastineeseen, hypoteesin vertailua muihin vastaaviin emootio- ja päätöksentekoteorioihin sekä pohtia hypoteesia laajemmassa tieteellisessä ja filosofisessa kontekstissa. Menetelmät. Kirjoitelmassa tuotiin esiin keskeisiä tutkimustuloksia, joita Damasio ym. ovat saaneet verrattaessa ventromediaalisen etuotsalohkon vauriosta kärsivien potilaiden ja verrokkiryhmäläisten välisiä eroavaisuuksia erilaisissa päätöksentekotilanteissa. Tulokset ja johtopäätökset. Somaattisten merkkitilojen hypoteesi oli iästään huolimatta edelleen relevantti eikä sitä korvaavaa uutta neurologista emootio- ja päätöksentekoteoriaa ole ilmaantunut eikä sen keskeisiä olettamuksia ole kumottu.