Psychophysics of Sequential Biases in Vision

Overseen By Valerie Ekko, BA

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of California, Berkeley

Disqualifiers: Under 18, Blind

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

1650 Participants Needed

Trial Summary

What is the purpose of this trial?

When looking at an x-ray, radiologists are typically asked to localize a tumor (if present), and to classify it, judging its size, class, position and so on. Importantly, during this task, radiologists examine on a daily basis hundreds and hundreds of x-rays, seeing several images one after the other. A main underlying assumption of this task is that radiologists' percepts and decisions on a current X-ray are completely independent of prior events. Recent results showed that this is not true: perception and decisions are strongly biased by past visual experience. Although serial dependencies were proposed to be a purposeful mechanism to achieve perceptual stability of otherwise noisy visual input, serial dependencies play a crucial and deleterious role in the everyday task performed by radiologists. For example, an x-ray containing a tumor can be classified as benign depending on the content of the previously seen x-ray. Given the importance and the impact of serial dependencies in clinical tasks, in this proposal, the investigators plan to (1) establish, (2) identify and (3) mitigate the conditions under which serial effects determine the participants' percepts and decisions in tumor search tasks. In Aim 1, the investigators will establish the presence of serial effects in four different clinically relevant domains: tumor detection, tumor classification, tumor position and recognition speed. In Aim 2, the investigators plan to identify the specific boundary conditions under which visual serial dependence impacts tumor search in radiology. In Aim 3, once the investigators fully understand these boundary conditions in Aim 2, they will propose a series of task and stimulus manipulations to control and mitigate the deleterious effects of visual serial dependence on tumor search. As a result of these manipulations, visual search performance should improve in measurable ways (detection, classification, position, speed). Aim 3 is particularly crucial because it will allow the investigators to propose new guidelines which will greatly improve tumor recognition in x-ray images, making this task even more effective and reliable. Taken together, the proposed studies in Aim 1, 2, and 3 will allow the investigators to establish, identify, and mitigate the deleterious effect of serial dependencies in radiological search tasks, which could have a significant impact on the health and well-being of patients everywhere.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment Psychophysics of Sequential Biases in Vision?

The research suggests that sequential context effects, where previous experiences influence current judgments, are present in perceptual decision-making. This understanding of how our brain processes sequences of information could help improve training methods for tasks that require quick and accurate visual judgments, like interpreting radiographic images. ^{1 2 3 4 5}

Is the treatment 'Psychophysics of Sequential Biases in Vision' safe for humans?

The research articles provided do not contain specific safety data for the treatment 'Psychophysics of Sequential Biases in Vision' or related interventions. ^{2 3 4 5 6}

How does the treatment 'Psychophysics of Sequential Biases' differ from other treatments for perceptual judgment biases?

This treatment is unique because it focuses on understanding and adjusting the biases in our perception that occur due to the sequence of previous stimuli, rather than targeting a specific condition with a standard drug or therapy. It uses insights from neural and cognitive models to explain and potentially modify how our judgments are influenced by recent experiences. ^{2 4 5 7 8}

Research Team

David Whitney, PhD

Principal Investigator

University of California, Berkeley

Eligibility Criteria

This trial is for individuals with normal or corrected-to-normal vision, such as those who wear glasses or contacts. It's designed to help radiologists improve their ability to detect and classify tumors in x-rays by understanding how previous images they've seen can affect their current work.

Inclusion Criteria

My vision is normal or corrected to normal with glasses or contacts.

Exclusion Criteria

I am 18 years old or older.

Subjects must not participate if they are blind.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Establishing Sequential Effects

Establish the presence of sequential effects in perceptual decision making in clinically relevant tasks such as tumor detection, classification, localization, and search times.

4-8 weeks

Multiple sessions (in-person)

Identifying Visual Serial Dependence

Identify the tuning and boundary conditions of visual serial dependence in tumor search to develop strategies to mitigate its harmful consequences.

4-8 weeks

Multiple sessions (in-person)

Mitigating Visual Serial Dependence

Develop task manipulations to mitigate the impact of visual serial dependence, improving visual search performance in radiologists.

4-8 weeks

Multiple sessions (in-person)

Follow-up

Participants are monitored for improvements in visual search performance and the effectiveness of mitigation strategies.

4 weeks

Treatment Details

Interventions

• No Intervention
• Psychophysics of Sequential Biases

Trial Overview The study investigates how past visual experiences bias a radiologist's perception and decisions when examining sequential x-rays. The goal is to establish these biases, identify conditions that influence them, and develop strategies to mitigate their negative effects on tumor detection and classification.

Participant Groups

Group I: Healthy Typical Adults Experimental Treatment 1 Intervention

Observers including radiologists and non-radiologists will be asked to participate in computer based tasks in which they visually search for, detect, localize, and categorize tumors in x-ray images.

Who Is Running the Clinical Trial?

University of California, Berkeley

Lead Sponsor

Trials

193

Recruited

716,000+

Findings from Research

In a study involving 20 experienced physicians and 20 medical students analyzing 234 complex radiographic images, only the medical students showed sequential context effects, indicating that their judgments were influenced by the order of images they viewed.

As medical students progressed through the training task, they shifted from making relative comparisons based on the sequence of images to relying more on their internalized standards for evaluating each image independently.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sequential dependencies in categorical judgments of radiographic images. Beckstead, JW., Boutis, K., Pecaric, M., et al.[2017]

Sequential effects in perceptual judgments, such as assimilation and contrast effects, show how our recent experiences influence our current perceptions, indicating a dynamic bias in judgment.

The proposed framework based on human M/EEG findings suggests that these sequential biases evolve over time and are integrated into our current judgments, helping to explain how we adapt our perceptions based on temporal context.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A neural-based account of sequential bias during perceptual judgment. Hsu, SM.[2021]

The study found that the way people perceive visual stimuli can influence their subsequent choices in a positive manner, while their motor responses can create a repulsive effect, indicating a complex interaction between perception and action.

Individual differences in how people experience serial dependence in decision-making were highlighted, with some showing a positive bias, others a repulsive bias, and some showing no bias at all, suggesting that these differences may stem from how much weight individuals give to perceptual choices versus motor responses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Individual difference in serial dependence results from opposite influences of perceptual choices and motor responses. Zhang, H., Alais, D.[2020]

Pseudosequential effects in psychophysical judgments can occur when some subjects inaccurately judge stimuli, which can skew results and lead to misleading conclusions.

Current methods for demonstrating genuine sequential effects are problematic, and there is still no definitive evidence proving that true sequence effects exist in psychophysical studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Sequence effects in absolute judgment? Critical comments on the method]. Haubensak, G.[2006]

The study reveals that our recent decisions influence how we perceive sensory information, suggesting that the brain continuously computes probabilities to predict future events, even in unpredictable environments.

By using different learning models in experiments with auditory, vestibular, and visual stimuli, the research shows that serial dependence in decision-making is linked to tracking statistical patterns rather than just the order of stimuli presented.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Probabilistic integration of preceding responses explains response bias in perceptual decision making. Schlunegger, D., Mast, FW.[2023]

In a study examining 3D motion perception, it was found that serial dependence—where decisions are influenced by previous stimuli—was stronger when the current trial had lower stimulus contrast, indicating a link between sensory uncertainty and bias.

Providing performance feedback, which reduced uncertainty, eliminated the serial dependence effect, suggesting that this bias may be a strategic response to manage uncertainty rather than a fixed perceptual mechanism.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Task feedback suggests a post-perceptual component to serial dependence. Fulvio, JM., Rokers, B., Samaha, J.[2023]

In a study involving 48 participants rating the attractiveness of male and female faces, it was found that attractiveness judgments are influenced by the ratings given in the preceding trial, demonstrating a sequential effect in subjective decision-making.

Providing participants with feedback on average attractiveness ratings from others reduced the sequential effect, indicating that external information can help mitigate biases in attractiveness judgments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sequential effects in face-attractiveness judgment. Kondo, A., Takahashi, K., Watanabe, K.[2017]

The study shows that past decisions can bias current perceptual choices, indicating that the influence of previous decisions is a significant factor in decision-making processes.

Using a modified drift-diffusion model, the research found that keeping track of previous decisions improves the accuracy of current decisions, suggesting that decision-making is influenced by the accumulation of evidence from prior choices.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Residual Information of Previous Decision Affects Evidence Accumulation in Current Decision. Olianezhad, F., Zabbah, S., Tohidi-Moghaddam, M., et al.[2020]

References

1. Netherlands pubmed.ncbi.nlm.nih.gov

Sequential dependencies in categorical judgments of radiographic images. [2017]

2. United States pubmed.ncbi.nlm.nih.gov

A neural-based account of sequential bias during perceptual judgment. [2021]

3. United States pubmed.ncbi.nlm.nih.gov

Individual difference in serial dependence results from opposite influences of perceptual choices and motor responses. [2020]

4. Germany pubmed.ncbi.nlm.nih.gov

[Sequence effects in absolute judgment? Critical comments on the method]. [2006]

5. United States pubmed.ncbi.nlm.nih.gov

Probabilistic integration of preceding responses explains response bias in perceptual decision making. [2023]

6. United States pubmed.ncbi.nlm.nih.gov

Task feedback suggests a post-perceptual component to serial dependence. [2023]

7. United States pubmed.ncbi.nlm.nih.gov

Sequential effects in face-attractiveness judgment. [2017]

8. Switzerland pubmed.ncbi.nlm.nih.gov

Residual Information of Previous Decision Affects Evidence Accumulation in Current Decision. [2020]