The speed of human visual perception

Vision is the primary sense people rely on to understand their surroundings and guide their daily activities. Due to its significance in human lives, vision stands out as the most extensively studied sensory modality (Hutmacher, 2019). For those embarking on an eye tracking journey, it is instrumental to grasp the concept of visual perception and the limitations of human ability to perceive the visual world. In this article, we explain visual perception, delve deeper into the speed of visual perception, how it is measured, and provide a list of factors that can influence perceptual processes.

What is visual perception speed, and how is it measured?

Visual perception is the process of reception and cognition of a visual stimulus (Lieberman, 1984), or simply put, it is the ability to make sense of what we see. The visual processing speed defines the time it takes to recognize, analyze, and correctly judge the visual stimulus (Owsley, 2013). For instance, the time it takes for a tennis player to perceive the ball’s direction and to decide how to return a serve would be considered the speed of the visual perception.

Experimentally, behavioral measures such as reaction times are used to assess the visual processing speed. In a go/no-go categorization task, participants are given a binary choice: to either respond with a “go” for a specific stimulus or withhold their response (a “no-go”) for a different type of stimulus. The minimum reaction time of a manual response in such a task is around 300ms (Rousselet et al., 2003). However, the measure considers both visual processing and motor command execution.

Eye movements are also used to gauge visual processing speed. In a similar go/no-go categorization task, the saccadic response toward the correct stimulus is initiated after only 120 ms (Kirchner and Thorpe, 2006). Interestingly, if one of the stimuli contains human faces, the saccadic response is faster than, say, an inanimate object, and takes only 100 ms (Crouzet et al., 2010). The estimated delay of saccade preparation and execution is around 20-25 ms (Schiller and Kendall, 2004), implying that the visual system only takes around 80-100ms to process the visual stimulus to generate a reliable response. 

Another way to estimate the speed of the visual perception is to measure the response after viewing the stimuli. In this way, one does not need to take into account the time required for a motor or saccadic response execution and can assess the minimum time needed to achieve meaningful visual comprehension. In one such experiment, the participants correctly identified the images seen for only 13 ms, suggesting a much faster visual perception than previously thought. The subjects were presented with images in the experiment, each shown for between 13 and 80 ms. The participants were presented with the target name (e.g., flowers) before or after the sequence of images and given two forced-choice pictures to identify the one presented in the sequence. After seeing the image for as little as 13ms, the subjects could identify the correct image above the chance level, reaching the maximum performance at 44ms (Bacon-Macé et al., 2007; Potter et al., 2014).

The speed of human visual perception can be measured through various methods, and the response speed, to a certain extent, is tied to the assessment methodology. Different types of visual stimuli may also require varying amounts of processing time. Notably, one of the swiftest recorded speeds for processing a meaningful visual stimulus is 13 milliseconds, as documented by Potter et al. in 2014. Further down, we listed additional factors that affect visual perception speed and can help you better grasp this intricate cognitive system.

Factors influencing visual perception speed

·  Speed vs. accuracy trade-off

The brain trades off visual perception accuracy for speed (Lenninger et al., 2023). The initial visual processing is quick but not very accurate.

·  Rapid visual categorization speed does not change with learning

The speed of processing of a specific visual processing mode, known as Rapid Visual Categorization, cannot be reduced by learning. It will take the same time to categorize a stimulus regardless of whether it is highly familiar or completely novel (Fabre-Thorpe et al., 2001).

·  The sweet spot of brain activity

Perception is an interplay between incoming visual stimuli and the current brain state. Brain state and neural excitability can influence visual perception speed and accuracy (Iemi and Busch, 2018; Ruzzoli et al., 2019).

·  Expectation ramps up the perception speed

Cueing the expected stimulus location or providing context about the upcoming stimulus can decrease visual processing time and improve accuracy (Bar, 2004).

·  Luminance matter

For well-lit, high-contrast stimuli, visual perception is faster and results in a greater quality of visual information than poorly-lit, low-contrast stimuli (Hunter et al., 2017).

Cited publications

Bacon-Macé, N., Kirchner, H., Fabre-Thorpe, M., & Thorpe, S. J. (2007). Effects of task requirements on rapid natural scene processing: From common sensory encoding to distinct decisional mechanisms. Journal of Experimental Psychology: Human Perception and Performance, 33(5), 1013–1026.

Bar, M. (2004). Visual objects in context. Nature Reviews Neuroscience, 5(8), Article 8.

Crouzet, S. M., Kirchner, H., & Thorpe, S. J. (2010). Fast saccades toward faces: Face detection in just 100 ms. Journal of Vision, 10(4), 16.

Fabre-Thorpe, M., Delorme, A., Marlot, C., & Thorpe, S. (2001). A limit to the speed of processing in ultra-rapid visual categorization of novel natural scenes. Journal of Cognitive Neuroscience, 13(2), 171–180.

Hunter, M., Godde, B., & Olk, B. (2017). Effects of absolute luminance and luminance contrast on visual discrimination in low mesopic environments. Attention, Perception, & Psychophysics, 79(1), 243–252.

Iemi, L., & Busch, N. A. (2018). Moment-to-Moment Fluctuations in Neuronal Excitability Bias Subjective Perception Rather than Strategic Decision-Making. eNeuro, 5(3), ENEURO.0430-17.2018.

Kirchner, H., & Thorpe, S. J. (2006). Ultra-rapid object detection with saccadic eye movements: Visual processing speed revisited. Vision Research, 46(11), 1762–1776.

Lenninger, M., Skoglund, M., Herman, P. A., & Kumar, A. (2023). Are single-peaked tuning curves tuned for speed rather than accuracy? eLife, 12, e84531.

Lieberman, L. M. (1984). Visual Perception versus Visual Function. Journal of Learning Disabilities, 17(3), 182–185.

Potter, M. C., Wyble, B., Hagmann, C. E., & McCourt, E. S. (2014). Detecting meaning in RSVP at 13 ms per picture. Attention, Perception, & Psychophysics, 76(2), 270–279.

Rousselet, G. A., Macé, M. J.-M., & Fabre-Thorpe, M. (2003). Is it an animal? Is it a human face? Fast processing in upright and inverted natural scenes. Journal of Vision, 3(6), 440–455.

Ruzzoli, M., Torralba, M., Morís Fernández, L., & Soto-Faraco, S. (2019). The relevance of alpha phase in human perception. Cortex, 120, 249–268.

Schiller, P. H., & Kendall, J. (2004). Temporal factors in target selection with saccadic eye movements. Experimental Brain Research, 154(2), 154–159.