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Petia Kojouharova

Petia Kojouharova
Research Centre for Natural Sciences

Doctor of Psychology

About

24
Publications
2,481
Reads
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123
Citations
Additional affiliations
October 2016 - present
Research Centre for Natural Sciences
Position
  • Research Fellow
September 2011 - present
Eötvös Loránd University
Position
  • Lab Member
Description
  • Mathematical Cognition Research Group

Publications

Publications (24)
Article
Full-text available
A forrásmonitorozás fejlődése során éretté váló szándékvezérelt folyamatok aktivitása segíti a múltbeli reprezentációk pontos előhívását, valamint az automatikus folyamatok működése okán betolakodó asszociatív reprezentációk gátlását. A forrásemlékezet fejlődésének kontextusában arra a kérdésre is választ kaphatunk, miként válnak egy tárgyhoz kapcs...
Article
Full-text available
In this mini-review, we summarized the results of 12 visual mismatch negativity (vMMN) studies that attempted to use this component as a tool for investigating differences between non-clinical samples of participants as well as the possibility of automatic discrimination in the case of specific categories of visual stimuli. These studies investigat...
Chapter
According to the dominant view in the literature, several numerical cognition phenomena are explained coherently and parsimoniously by the Approximate Number System (ANS) model, which supposes the existence of an evolutionarily old, simple representation behind many numerical tasks. We offer an alternative account that proposes that only nonsymboli...
Article
Full-text available
The human face is one of the most frequently used stimuli in vMMN (visual mismatch negativity) research. Previous studies showed that vMMN is sensitive to facial emotions and gender, but investigations of age-related vMMN differences are relatively rare. The aim of this study was to investigate whether the models’ age in photographs were automatica...
Article
Full-text available
While knowledge on the development of understanding positive integers is rapidly growing, the development of understanding zero remains not well-understood. Here, we test several components of preschoolers’ understanding of zero: Whether they can use empty sets in numerical tasks (as measured with comparison, addition, and subtraction tasks); wheth...
Article
Full-text available
We investigated the effects of distractors in older and younger participants in choice and simple reaction time tasks with concurrent registration of event-related potentials. In the task the participants had to prevent a disk from falling into a bin after a color or luminosity change (target stimuli). Infrequently, task-irrelevant stimuli (schemat...
Preprint
According to the dominant view in the literature, several numerical cognition phenomena are explained coherently and parsimoniously by the Approximate Number System (ANS) model, which model supposes an evolutionarily old, simple representation behind many numerical tasks. We offer an alternative model, the Discrete Semantic System (DSS) to explain...
Article
Full-text available
In the number comparison task distance effect (better performance with larger distance between the two numbers) and size effect (better performance with smaller numbers) are used extensively to find the representation underlying numerical cognition. According to the dominant analog number system (ANS) explanation, both effects depend on the extent...
Article
Full-text available
We investigated the effects of voluntary hand movements and continuously present objects on the automatic detection of deviant stimuli in a passive oddball paradigm. The visual mismatch negativity (vMMN) component of event-related potentials (ERPs) was measured as the index of automatic deviant detection. The stimuli were textures consisting of par...
Article
Full-text available
The present study investigated the function of the brain activity underlying the visual mismatch negativity (vMMN) event-related potential (ERP) component. Snowflake patterns (complex stimuli) were presented as deviants and oblique bar patterns (simple stimuli) as standards, and vice versa in a passive oddball paradigm. Control (equiprobable) seque...
Article
Full-text available
Visual mismatch negativity (vMMN), an event-related signature of automatic detection of events violating sequential regularities is traditionally investigated at the onset of frequent (standard) and rare (deviant) events. In a previous study we obtained vMMN to vanishing parts of continuously presented objects (diamonds with diagonals), and we conc...
Article
In the symbolic number comparison task, the size effect (better performance for small than for large numbers) is usually interpreted as the result of the more general ratio effect, in line with Weber's law. In alternative models, the size effect might be a result of stimulus frequency: smaller numbers are more frequent, and more frequent stimuli ar...
Preprint
Full-text available
Visual mismatch negativity (vMMN), an event-related signature of automatic detection of events violating sequential regularities is traditionally investigated to the onset of frequent (standard) and rare (deviant) events. In a previous study [4] we obtained vMMN to vanishing parts of continuously presented objects (diamonds with diagonals), and we...
Article
Full-text available
HIGHLIGHTSWe test whether symbolic number comparison is handled by an analog noisy system. Analog system model has systematic biases in describing symbolic number comparison. This suggests that symbolic and non-symbolic numbers are processed by different systems. Dominant numerical cognition models suppose that both symbolic and non-symbolic number...
Article
Full-text available
In a comparison task, the larger the distance between the two numbers to be compared, the better the performance—a phenomenon termed as the numerical distance effect. According to the dominant explanation, the distance effect is rooted in a noisy representation, and performance is proportional to the size of the overlap between the noisy representa...
Preprint
Dominant numerical cognition models suppose that both symbolic and nonsymbolic numbers are processed by the Analogue Number System (ANS) working according to Weber’s law. It was proposed that in a number comparison task the numerical distance and size effects reflect a ratio-based performance which is the sign of the ANS activation. However, increa...
Preprint
In a comparison task, the larger the distance between the two numbers to be compared, the better the performance, a phenomenon termed the numerical distance effect. According to the dominant explanation, the distance effect is rooted in a noisy representation, and performance is proportional to the size of the overlap between the noisy representati...
Preprint
Full-text available
While the knowledge about the development of understanding positive integers is rapidly growing, the development of understanding zero is not well-known. Here we tested several components of preschoolers’ understanding zero: whether they can use empty sets in numerical tasks, whether they can use empty sets as soon as they understand the cardinalit...
Article
Full-text available
Our aim was to review the results of published empirical research on the physical and psychological effects of aikido training. Aikido is an Eastern, non-competitive martial art form that is usually practiced for the purposes of recreation and spiritual development. How central concepts of the aikido philosophy, such as “do no harm”and “soft confli...
Article
Full-text available
Human number understanding is thought to rely on the analog number system (ANS), working according to Weber’s law. We propose an alternative account, suggesting that symbolic mathematical knowledge is based on a discrete semantic system (DSS), a representation that stores values in a semantic network, similar to the mental lexicon or to a conceptua...
Article
Human number understanding is thought to rely on the analogue number system (ANS), working according to Weber’s law. We propose an alternative account, suggesting that symbolic mathematical knowledge is based on a discrete semantic system (DSS), a representation that stores values in a semantic network, similar to the mental lexicon or to a concept...

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Projects

Projects (2)
Project
We investigate how preschoolers understand numbers, starting from the very beginning of understanding symbolic numbers (i.e., understanding the cardinality principle), until they start formal math education.
Project
Symbolic and non-symbolic numbers are thought to be processed by an evolutionary ancient, simple representation, the Analogue Number System (ANS), which system is thought to be the very base of number understanding. We offer an alternative account for symbolic number understanding, proposing a human specific, simple representation similar to a network of concepts or to the mental lexicon. It is a comprehensive model for symbolic number processing phenomena. See more details at http://www.thenumberworks.org/discrete_semantic_system.html