Degree theses are also assigned in the areas of research mentioned.
Interested students can see Dr. Niedeggen, Professor, during office hours for further information.
Using two paradigms (temporal and visual/spatial direction of attention), we examine whether the quality of the perception (stimulus perception) is dependent on the distraction of the focus of attention or on the free resources. Neurobiological methods are used to identify the site of the interaction within the cortex.
Two methods of inducing a transient perceptual disturbance are used. Researchers use the paradigm of “motion blindness” to examine the prerequisites for conscious perception of the simplest visual stimuli. Our behavioral and EEG studies have shown that while the level of sensory activation permits prediction of the experienced strength of the stimulus, it is not sufficient as a predictor of conscious visual representation. The method of “change blindness” allows us to examine the transition from unconscious to conscious visual perception. The phenomenon of change blindness also gives us insight into how the brain stores information on its environment: Visual representations seem to be primarily affected by the first impression.
A paradigm for the induction of a type of experimental blindness, partial repetition blindness, can be used in a targeted fashion to create illusionary words. We have been able to show that these illusions are generated at an early stage of word processing in the brain and that their electrophysiological signature is indistinguishable from that of a real word. Our results have also shown that this phenomenon is subject to a neuronal “winner-take-all” model. The brain structures involved have been identified using MEG examinations. We are planning a new research project to use this paradigm to examine unconscious processing of words with affective associations.
We aim to use a computer-assisted testing method that measures the categorization of emotional states in faces to develop a multidimensional model for the decoding of emotions. The main question we are examining in our research on this topic is what measure of categorization of emotional facial expressions is reflected in automatic, genetically determined processes and what measure is determined by learned skills. We use behavioral and neurobiological methods to look at these issues.
Like the effect of motion blindness (see No. 1 above), the phenomenon of negative priming is also explained through the activation of an inhibition mechanism. Alternatively, however, the delayed reaction to what has previously been an impeded stimulus can also be explained through episodic memory processes. The aforementioned approach to explaining this phenomenon has found support in evidence from ECP studies. We are planning additional trials to further specify the memory process involved.
In connection with the book entitled Visuelle Wahrnehmungsstörungen (Visual Perceptual Disturbances) (Niedeggen & Jörgens, 2005, Hogrefe-Verlag), we have developed a test program that examines a series of functions that fall outside of standard neuropsychological examinations.
The program (screening of visual perception functions) should run on (almost) any PC that runs Windows. We are currently working on the program to make it even easier to use and to expand the range of visual functions covered.