OBJECTIVEThe Muller-Lyer illusion is a visual illusion in which a horizontal shaft with an inward-pointing chevron (fins-out) affixed to each end is perceived longer than a shaft with outward-pointing chevrons (fins-in). The goal of this study was to compare the effects of experience and knowledge about the Muller-Lyer illusion on participants' perceptual precision.

METHODSParticipants were undergraduate students (n = 108) who were not familiar with the Muller-Lyer illusion prior to the experiment. The task of participants was to adjust one movable line to make it equal to the other in Muller-Lyer figure. They received ascending and descending Muller-Lyer trials in three blocks with 20 trials each. The Experimental Group received information about the Muller-Lyer illusion prior to the third block.

RESULTSFor the Experimental Group, the amount of departure in Block 3 was reduced significantly compared with previous blocks.

CONCLUSIONKnowledge about the mechanisms underlying visual illusions may play an important role in helping individuals overcome them.

Adult ; Brain ; physiology ; Cognition ; physiology ; Female ; Humans ; Illusions ; physiology ; Learning ; physiology ; Male ; Models, Neurological ; Neuropsychological Tests ; Orientation ; physiology ; Pattern Recognition, Visual ; physiology ; Photic Stimulation ; Sex Characteristics ; Visual Perception ; physiology

PURPOSE: Firefighters are exposed to high levels of occupational risk factors, such as safety risks, chemical, ergonomic, and physical hazards that may jeopardize their lives. To overcome these hazards, firefighters must be physically, mentally, and personally fit to work. This study aimed to explore the criteria and factors affecting firefighters' resilience based on stakeholders' experiences. METHODS: This qualitative study was carried out using conventional content analysis. In total, 21 face-to-face interviews were conducted by firefighters who were experienced in the field. The interviews were carried out from July 2019 to January 2020. The data were collected using 3 unstructured interviews and then resumed by 18 semi-structured interviews. Data analysis was done using Graneheim method. RESULTS: The participants had more than 5 years of experience in the field of search and rescue. The extracted codes through data analysis were classified into 3 main categories (individual, organizational, and social factors), 9 sub-categories (mental, physical, occupational, managerial, colleagues-related, equipment-related, environmental, community-related, and family-related factors), as well as 19 sub-sub-categories and 570 codes. CONCLUSION Firefighters' personality, physical condition, behavior and psychological characteristics can affect their resilience along with organizational and management factors that play significant role in people's safety. Developing a tool for assessing resilience can help decision makers to have a real depict of firefighters' job qualifications.
Firefighters/psychology* ; Humans ; Qualitative Research