Ability To Efficiently Process Local Stimuli Psychology Essay

Ability To Efficiently Process Local Stimuli Psychology Essay This study is a replication of Navons third experiment in his 1977 paper Forest Before Trees. Participants are shown a large letter the global stimulus made up of smaller letters the local stimuli. The small and large letters are either consistent or contradictory. Participants were asked to identify the local stimuli. The aim was to determine whether global stimuli affected the reaction time of identifying local stimuli when the two are incongruent. 51 undergraduate students took part in the study which was an opportunity sample. This was a laboratory experiment of a repeated measures design. It was found that a contradicting global stimulus significantly affects the reaction time of identifying the local stimulus. From the results collected it can be concluded that global processing does affect local processing when the two figures are inconsistent and that incongruent stimuli cause a significantly delayed response to identifying the local stimuli. Is our ability to perceive and r ecognise local stimuli affected when local and global stimuli are incongruent? According to the theory of bottom-up processing, the whole is built up from its individual components. This would suggest that we first identify the local stimulus before perceiving the global one, implying that our ability to recognise the local stimulus should not be affected by the global one. However the Gestaltist law of common fate contradicts this in suggesting that we perceive the global stimulus as all of the local stimuli are positioned together to form it. Navon (1977) suggested in his paper ‘Forest Before Trees: The Precedence of Global Features in Visual Perception’ that we initially perceive the global structure and proceed to break it down to identify its components. He tested this by showing participants a large letter composed of smaller letters arranged to form the shape of the large letter. The small and large letters were either congruent or incongruent, and participants h ad to identify the small letter as quickly as possible. In this study, Navon’s original experiment was replicated to test whether the global letter affects the time taken to identify the local letter, comparing between when these letters are congruent or incongruent. The purpose of this study was to compare our findings to those already existing from Navon’s experiment to either corroborate or contradict his findings, and then discuss the possible explanations for the manner of global and local processing and how this can be applied to the real world and implicate possible future research. This study looks at whether global or local stimuli are perceived first and whether incongruence between them affects the speed at which they are recognised. Based on Navon’s findings, we expect that there will be an effect on reaction time when the local and global letters are incongruent, with it taking a significantly longer time to identify the local stimuli compared to wh en all stimuli are congruent. Method Design: This experiment was a laboratory experiment with a repeated measures design, in that the same group of participants performed the task a number of times in a row. The independent variable was the congruence of the stimuli, and the dependent variable being measured was the participant’s reaction time in seconds. The independent variable is nominal and the dependent variable is linear. All participants were tested at the same time under the same conditions, in the same setting; however this cannot account for personal factors such as attention or fatigue.