Related Experiment Video
Updated: Jun 19, 2026
07:13
A Two-interval Forced-choice Task for Multisensory Comparisons
Published on: November 9, 2018
Characterizing perceptual performance at multiple discrimination precisions in external noise
Seong-Taek Jeon1, Zhong-Lin Lu, Barbara Anne Dosher
1Laboratory of Brain Processes (LOBES), Department of Psychology, and Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089, USA.
Summary
We enhanced the perceptual template model (PTM) to accurately model human performance in identifying non-orthogonal targets under external noise. This provides a new framework for understanding joint feature and contrast sensitivity.
Area of Science:
- Visual perception
- Human observer modeling
- Psychophysics
Background:
- Current observer models are limited to orthogonal targets in external noise paradigms.
- Accurate modeling is needed for non-orthogonal target identification.
Purpose of the Study:
- To elaborate the perceptual template model (PTM) for non-orthogonal target identification.
- To model contrast thresholds and observer performance under varying noise levels.
Main Methods:
- Measured full contrast psychometric functions in an orientation identification task.
- Utilized an external noise paradigm with varied orientation differences.
- Applied an elaborated PTM with two templates.
Main Results:
- Observer performance in identifying non-orthogonal targets was successfully modeled by the elaborated PTM.
- Sampling efficiencies of human observers were estimated.
- The model accounts for joint feature and contrast sensitivity.
Conclusions:
- The elaborated PTM offers a robust framework for analyzing visual search and identification.
- This model extends beyond orthogonal targets, improving understanding of human visual capabilities.
Related Concept Videos
01:21Perceiving Loudness, Pitch, and Location
The human brain perceives pitch through two primary mechanisms reflected in place theory and frequency theory. Each mechanism describes how sound waves are interpreted as specific pitches by the brain, offering insights into the intricate processes of auditory perception.
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...
01:17Auditory Perception
The auditory system is essential for sound perception, utilizing various critical structures. When sound waves enter the outer ear, they travel through the ear canal and cause the eardrum to vibrate. These vibrations are then transmitted to the middle ear, where three tiny bones – the malleus, incus, and stapes – amplify the sound. This amplification is crucial, as it ensures that the sound vibrations are strong enough to be conveyed to the inner ear. These vibrations then reach the cochlea, a...
01:01Perception of Sound Waves
The human ear is not equally sensitive to all frequencies in the audible range. It may perceive sound waves with the same pressure but different frequencies as having different loudness. Moreover, the perception of sound waves depends on the health of an individual's ears, which decays with age. The health of one's ears may also be affected by regular exposure to loud noises.
The pitch of a sound depends on the frequency and the pressure amplitude of the source. Two sounds of the same frequency...
The pitch of a sound depends on the frequency and the pressure amplitude of the source. Two sounds of the same frequency...
01:25Factors Affecting Perception
Perception is influenced by perceptual set, context, motivation, and emotion. Perceptual set, or perceptual expectancy, refers to the tendency to perceive things in a particular way, influenced by previous experiences and expectations. This phenomenon affects the interpretation of stimuli, creating a set of mental tendencies and assumptions that impact sensory perceptions of sound, taste, touch, and sight.
An illustrative example of a perceptual set is the scenario where an airline pilot told...
An illustrative example of a perceptual set is the scenario where an airline pilot told...
01:05Difference from Background: Limit of Detection
The limit of detection (LOD) is the smallest amount of analyte that can be distinguished from the background noise. The LOD value corresponds to the concentration at which the analyte signal is three times larger than the standard deviation of the blank signal. Below this value, the analyte signal cannot be differentiated from the background noise. It is calculated by dividing the calibration slope by 3 times the standard deviation of the blank signals.
The LOD indicates the presence or absence...
The LOD indicates the presence or absence...
01:12Perceptual Constancy
Perceptual constancy is the ability to recognize that objects remain consistent and unchanged even when their appearance varies due to changes in sensory input. There are four main types of perceptual constancy: size constancy, shape constancy, color constancy, and brightness constancy.
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...