Simons, D., & Chabris, C. (1999). Gorillas in Our Midst: Sustained Inattentional Blindness
for Dynamic Events. Perception, (28) 1059-1074.
Arhe Vaninetti
Research Methods and Statistics, PSY301, Pacific University, Oregon
March 13, 2023
In Simons & Chabris’ (1999) study on perception and inattentional blindness, they aimed to create a comprehensive study that highlighted previous research on the topic, as well as to expand and consolidate their additional research. For this study, the researchers examined where attention is focused (mainly around a stimulus and not on it), as well as established typical methodology from previous studies (i.e., Neisser and Becklen, 1975). From these previous studies, Simons & Chabris (1999) suggest that the experiments on inattentional blindness could have been improved with varying task difficulty, and direct comparisons with the superimposed (transparent) versions of the videos and with the opaque versions of the videos.
In the methodology, the researchers decided that, for their study, they would include all of the components that other studies did not. They created 4 videos: Transparent Umbrella Woman, Transparent Gorilla, Opaque Umbrella Woman, and Opaque Gorilla. This meant that for each unexpected stimulus (either a person in a gorilla suit, or a woman with an umbrella walking across the screen), the video was edited to either have the basketball players be transparent or opaque. From there, they created 4 task conditions: White/Easy, White/Hard, Black/Easy, and Black/Hard. This meant that the participant would either track the basketball players in the white shirts or black shirts, and they would be tasked with either counting how many total basketball passes were made (in the easy condition), or with counting how many dribble passes were made as well as normal basketball passes (in the hard condition). This made for a total of 16 sessions that participants could be assigned to.
The researchers collected 228 participants (mainly undergraduate students) through either volunteer or compensated efforts. When the videos were displayed to the participants, and the participants were instructed to watch the video while paying attention to one shirt color and different types of basketball passes, the unexpected stimulus would enter the screen at around 44 to 48 seconds, and would leave the screen after walking across over the course of 5 seconds. With 12 participants in each condition, and each participant taking 5-10 minutes, this was a quick paced experiment that required 21 researchers to coordinate.
In the results section, across all conditions, 54% noticed the unexpected event and 46% failed to notice the unexpected event, which were results consistent with previous studies. With the 2x2x2x2 ANOVA and subsequent analysis, the researchers were able to suggest that the participants in the easy condition were able to notice the unexpected event more than the participants in the hard condition (64% as compared to 45%, respectively). Furthermore, the umbrella woman was noticed more often than the gorilla (65% as compared to 44%, respectively).
In the discussion, the researchers stated how they found that visual stimuli that are not attended to are often drowned out with other stimuli that are attended to. Essentially, inattentional blindness is often due to focusing on certain objects over others, or becoming desensitized to other stimuli. This study may be enhanced by including further conditions with live stimuli and unexpected events. It may be that the video screen ‘flattens’ the action and the lack of depth awareness causes the participants to miss the unexpected stimuli. Perhaps this experiment could happen live on a stage, so that the unexpected stimuli could pass across the stage and disappear again. Furthermore, limiting the unexpected stimuli to a person walking across may be causing the participants to miss the stimuli—especially considering how different cultures look at or don’t look at faces, bodies, etc. There may be an element of culture that is not accounted for.