Evaluation of oblique effect via eye tracking and fNIRS techniques on perceptual fluency and preference behavior.

All the stimuli we perceive in the environment are on a continuum. This perception initiates cognitive processes from low-level visual cues to context-appropriate decision-making processes in semantic integrity. Contours are the main starting point in reaching the three-dimensional representation of an object in the mind, starting from its two-dimensional state. However, the ease of operation in perceiving an object shapes the person's approach to that object. Ease of cognitive processes positively affects one's attitude. Despite the fact that cortical areas are crucial for processing, interpreting, and making appropriate judgments, as an integration hub, the prefrontal cortex provides the control of executive processes. The current thesis study aimed to investigate the effects of curved contours that cause positive emotions and sharp contours that contain an implicit threat cue on the prefrontal cortex and attention in perception and decision-making processes. In addition, the relationship between contour types and aesthetic perception will also be investigated. In the current thesis, a survey was used to analyze the preference tendencies of people according to contour types. Then, the fNIRS method was used to examine the activation changes in the prefrontal cortex while perceiving the images and making the decision to like/dislike the images. Then, the eye-tracking method was used to examine the nature of attention and eye movements while examining the images. As a result of the research, it has been demonstrated that people prefer curved contoured objects significantly more compared tos harp contoured objects when choosing real-world items to employ in their daily lives. However, it has been shown that sharp and rounded contours cause different activations in the prefrontal cortex regions, and rounded contours have a positive effect on processing fluency. Keywords: Contour types, PFC, perception, fNIRS