Related Experiment Video
Updated: May 31, 2026
07:26
Assessing Pupil-linked Changes in Locus Coeruleus-mediated Arousal Elicited by Trigeminal Stimulation
Published on: November 26, 2019
Keeping an eye on the truth? Pupil size changes associated with recognition memory.
1School of Psychology, University of Sussex, Brighton, UK.
Memory (Hove, England)
|June 17, 2011
Summary
Pupil dilation increases when people see familiar items, a phenomenon known as the pupil old/new effect. This involuntary response occurs regardless of instructions, suggesting potential for detecting feigned memory loss in clinical settings.
Area of Science:
- Cognitive Psychology
- Neuroscience
- Ophthalmology
Background:
- Recognition memory tests often reveal differences in physiological responses between correctly identified old and new items.
- The pupil old/new effect, an increase in pupil dilation to previously encountered items, has been observed but requires further investigation into its controllability.
Purpose of the Study:
- To replicate the pupil old/new effect in a controlled setting.
- To investigate the relationship between pupil dilation during recognition memory tasks and explicit participant responses under varying instructions.
- To assess the potential of the pupil old/new effect as a biomarker for detecting deception in memory recall.
Main Methods:
- Participants underwent recognition memory tests under three distinct instruction sets: standard, feigned amnesia, and reporting all items as new.
- Changes in pupil size were continuously monitored and analyzed during the presentation of old and new visual stimuli.
- Behavioral responses (old/new judgments) were recorded for each item.
Main Results:
- A significant increase in pupil dilation was consistently observed when participants viewed old items compared to novel items across all instruction conditions.
- The pupil old/new effect persisted even when participants were instructed to feign amnesia or deny recognition.
- No significant modulation of the pupil old/new effect was found based on the explicit response strategy employed by the participants.
Conclusions:
- The pupil old/new effect appears to be an involuntary physiological response, not easily suppressed by conscious effort or deceptive instructions.
- This robust and measurable effect holds promise for objective assessment of memory, potentially aiding in the diagnosis of genuine memory impairment versus malingering.
- Further research is warranted to explore the clinical utility and refine the application of pupil dilation measurements in neuropsychological evaluations.
Related Concept Videos
01:22Eyewitness Memory
Eyewitness memory refers to the recollection of events by someone who has directly witnessed them, often serving as critical evidence in legal settings. This type of memory is commonly used in criminal cases where a witness describes details like a suspect's appearance, clothing, or behavior during a crime. However, despite its perceived reliability, eyewitness memory is prone to significant errors.
One such error is memory distortion, which occurs because human memory does not function like a...
One such error is memory distortion, which occurs because human memory does not function like a...
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...
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...