Project

vision; perception; cognition; pre-attentive processing; attention; selective processing; cognitive neuropsychology; selection; selective attention; psychophysics; psychophysiology; eye movements; attention deficit disorder

Lead
Lay summary
The project is aimed at investigating mechanisms of visual selection using, in an integrative approach, methods of cognitive experimental psychology (reaction times), psychophysiology (event-related potentials) and eye movement recording. The methods are applied to compare visual search performance in participants with disturbances of selective attention to the results of unimpaired observers. The project involves four research foci.Focus 1 investigates the relationship between attention and eye movements in feature and compound visual search tasks. Own research shows that dimensional and spatial weighting processes modulate search performance differently in these two search types. Reaction time and eye movement analyzes are employed to investigate the relationship between the mechanisms underlying the allocation of focal attention and those controlling saccadic eye movements. Dimension-based and spatial effects will be analyzed with respect to early (e.g., saccade latency) and late (e.g., fixation duration) processing stages.Focus 2 employs hidden Markov models to investigate the mechanisms underlying intertrial transition effects. It is generally assumed that reaction time modulations reflected in mean reaction times are due to trial-by-trial modulations of processing resources. The project aims at investigating this claim by comparing experimental data with model predictions.Focus 3 is aimed at identifying the component mechanisms of attentional selection altered in attention deficit disorders and autistic impairments. In a systematic investigation of the component processes of visual attention - working memory, processing speed, top-down control - selective performance in observers with and without attention disorders is compared. People suffering from autistic disturbances have repeatedly been shown to outperform normal controls in attention tasks. The component processes underlying this search performance advantage are investigated in participants with Asperger's syndrome to identify component mechanisms giving rise to the benefit.Focus 4 uses electroencephalography (EEG) to assess, with high temporal resolution, the processes underlying signal integration within and across modalities in healthy and impaired observers in selection tasks.The proposed research is expected to contribute to the understanding of the component mechanisms underlying the control of selective information processing. By comparing unimpaired and impaired performances, theoretical constraints of experimental psychology and cognitive neuropsychology will be met in order to extend the theoretical models proposed to explain the key human ability of information selection.

Direct link to Lay Summary

Last update: 21.02.2013

Self-organised

Number	Title	Start	Funding scheme

While the objectives of the first period of the SNF professorship project “” were met, a series of important issues emerged from this research. These research questions are directly linked to findings of previous studies and it is proposed to address the issues in a two-year extension of the professorship using the infrastructure established at the Department of Psychology of the University of Fribourg.Continuing the concept of neuro-cognitive psychology comprising the various fields or research involved in cognitive empirical psychology, the planned research is in three main areas using different research methods. The methodological approach is based on procedures of experimental psychology such as the psychophysical approach, analysis of reaction times and accuracy of performance. Methods are complemented by techniques of eye movement recording aimed at investigating the relationship between attention and the control of saccadic eye movements. In addition, electroencephalographic measures are used to investigate mechanisms of selective attention on a high-frequency temporal scale. These methods are applied to questions of cognitive neuropsychology in a research focus planned to examine people with impairments in attentional mechanisms. In particular, children and young adults suffering from attention deficit hyperactivity disorder on the one hand and from autistic disorders such as Asperger’s syndrome will be examined in order to identify component processes responsible for the disorders. In addition a modeling approach will be used to examine the exact mechanism underlying effects of intertrial modulations on search reaction times.In detail, research focus 1 is aimed at investigation the relationship between attention and eye movements in feature and compound search tasks. Own research has shown that dimensional and spatial weighting processes modulate search performance differently in feature detection and compound search tasks: in detection tasks, the dimension defining the target in the previous trial affects search reaction times in the present trial; in compound tasks, however, spatial effects are more marked and dimensional effects are greatly reduced. Search reaction times and eye movement parameter will be recorded to attribute the differential effects to early (as reflected, e.g., by saccade latency) or late (as reflected by fixation durations) stages of processing. Research project 2 employs hidden Markov models to investigate the mechanisms underlying intertrial transition effects. It is generally assumed that reaction time modulations reflected in mean reaction times of different types of intertrial transitions are due to trial-by-trial modulations of processing resources attributed to different processing modules. Research project 2 aims at investigating this claim by comparing experimental data with model predictions. Research focus 3 is aimed at identifying the component mechanisms of attentional selection affected in attention deficit disorders with or without a hyperactivity component and in people suffering from autistic impairments. As systematic investigations into component processes of attention are not available yet, it is proposed to assess modifications of component processes such as working memory, processing speed, top-down control and lateralization in children with and without attention disorders. People suffering from autistic disturbances have repeatedly been shown to outperform normal controls in attention tasks. Again, systematic investigations into the component processes underlying this performance advantage have not been attempted yet and it is proposed to contribute to the understanding by testing participants with Asperger’s syndrome (an autism spectrum disorder) and Autism in various search tasks that are well understood. Research focus 4 uses electroencephalography (EEG) to assess, with high temporal resolution, the processes underlying signal integration within and across modalities in healthy and impaired observers. The proposed research is expected to contribute significantly to the understanding of the component mechanisms underlying the control of selective information processing. By comparing unimpaired and impaired performances, theoretical constraints of both experimental and cognitive will be met in order to further extend the knowledge of cognitive models proposed to explain the key human ability of information selection.