Note
Studied by 56 peoplePY2501 between subjects ANOVA with 2 IVs(1) - Tagged
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Session Information:
Aston University Birmingham
Join at: vevox.app
Subjects ID: ANOVA with 2+ IVs 187-498-854
Presenter: Ed Walford
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Learning Outcomes:
Understand the purpose of a multiple ANOVA.
Conduct multiple ANOVA in Jamovi.
Interpret Jamovi output for multiple ANOVA.
Report results of multiple ANOVA.
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Page 4: History of Psychophysics
Early discipline in experimental psychology.
Gustav Fechner coined the term ‘psychophysics’ in 1860.
His work focused on the relationship between ‘matter and mind’; foundational in psychology as a science.
Fechner (1801-1887).
Page 5: Definition of Psychophysics
Importance of the physical properties of stimuli: content, magnitude, timing.
Psychophysics defined as:
“The analysis of perceptual processes by studying the effect on a participant’s experience or behaviour of systematically varying the properties of a stimulus along one or more physical dimensions.”
Source: Bruce V, Green PR, Georgeson MA (1996). Visual perception. Psychology Press.
Page 6: Importance of Studying Perception
Significant focus on perception in psychology; 50% of the cortex is dedicated to it.
All actions stem from sensation, influencing emotions, imagination, and perceptions of reality.
Realization that perception is subjective; influenced by age, gender, and disability.
Page 7: Experiment Design vs. Procedure
Elements of Experimentation
Procedure: Manipulation, Measure, Task, Stimulus Selection.
Hypothesis Testing: Analysis and Statistics.
Importance of systematic modeling in psychophysics.
Page 8: Elements in Psychophysics Procedure
Four Key Elements
Manipulation:
Masking, Facilitation/Priming, Contrast effects, Adaptation.
Measurement:
Percent correct, Thresholds, Bias.
Appearance:
Point of Subjective Equality (PSE).
Task:
Single Interval Yes/No, Two Alternative Forced Choice (2AFC), Single Interval Symmetric Choice.
Stimulus Selection Method:
Constant stimulus, Adaptive, Method of limits, Adjustment.
Page 9: Comparison of Psychophysics and Cognitive Psychology
Key Differences
Cognitive Psychology:
Focus on mental processes, long-duration present stimuli, complex stimuli interpretation.
Primary measure: Reaction Time; secondary measure is accuracy.
Psychophysics:
Focus on sensory processes, brief stimuli, and simple compositions.
Primary measure: Accuracy; Reaction Times often disregarded.
Page 10: Psychophysics vs Cognitive Psychology
Illustrative depiction of the concepts of stimulus and response processes.
Humorously highlights the distinction between focus on observable stimuli vs mental interpretations.
Page 11: Applications of Psychophysics
Senses Studied
Vision: Intensity of light, color perception, orientation, depth, motion.
Hearing: Sound loudness, pitch, direction.
Touch: Pressure intensity, texture.
Taste: Flavour intensity, variations.
Smell: Odor intensity, identification.
Page 12: Visual Psychophysics Aspects
Types of Stimuli
Key focus on visual aspects:
Intensity, Contrast, Orientation, Size, Depth, Motion, Color, Texture.
Page 13: Measuring Thresholds
Investigating perception limits:
How well stimuli can be sensed (seen, heard, felt, etc.).
Identifying the weakest stimulus perceivable.
Page 14: Example: Contrast Sensitivity
Key inquiry: Visibility of patterns at varying sizes.
Manipulating stimuli with differing spatial frequencies and assessing responses.
Page 15: Experiment Design Considerations
Referenced studies exhibit approaches in assessing contrast sensitivity with stimuli.
Page 16: Peak Frequency and Acuity Limits
Differentiation between infant and adult detection capabilities with spatial frequency tests (limited range of responses).
Page 17: Poor Threshold Measurement Methods
Challenges with Single Interval Yes-No designs.
Participants asked to respond to always-present stimuli; potential for bias in responses.
Page 18: Estimating Thresholds
The Psychometric Function
Characterization of detection as probabilistic, deriving curves from responses to estimate detection thresholds at 50% accuracy.
Page 19: Challenges of Bias in Measurement
Understanding participant tendencies towards bias based on stimulus strength or personal inclination to respond positively.
Page 20: Bias Condition Examples
Exploration of participant sensitivity or willingness to respond positively under varying experimental conditions.
Page 21: Effective Measurement Techniques
Use of Two Alternative Forced Choice tasks to mitigate bias across stimuli arrangements.
Page 22: Two-Alternative Forced Choice Tasks: Spatial Intervals
Detailed processes in assessing participant accuracy related to spatial interval placement of stimuli.
Page 23: Two-Alternative Forced Choice Tasks: Temporal Intervals
Examining participant's responses in assessing stimulus presence in distinct temporal slots.
Page 24: Estimating Thresholds with Psychometric Functions
Analyzing curves in relation to detection of stimuli across various strength levels.
Page 25: Bias Evaluation in Two-Alternative Forced Choice
Discusses potential biases in two-alternative options and the importance of careful instructions to avoid inducing bias.
Page 26: Discrimination Thresholds
Evaluation methods for stimulus discrimination capabilities using different tasks.
Page 27: Summary of Threshold Measures and Tasks
Percent correct calculated from trials and plotted to derive psychometric functions and thresholds.
Page 28: Course Completion
End notes and readiness for assessment on the topic material covered.
Page 29: Manipulating Thresholds
Overview
Exploration of responses to various stimulus flavors, focusing on simultaneous and sequential presentations.
Page 30: Evaluating Visual Properties
Further exploration in understanding stimulus properties and perception throughout development stages (infants vs adults).
Page 31: Simultaneous Masking and Facilitation
Explaining the impacts of strong and weak stimuli on perceptual capabilities.
Page 32: Sequential Masking and Priming
Discussion on sequential exposure influencing perception through priming effects.
Page 33: Principles of Masking and Facilitation
Evaluates mechanisms behind perceptual changes based on subtleties in stimulus composition.
Page 34: Course Segment Completion
End of part 3 quiz questions and reflection opportunity.
Page 35: Measuring Appearance
Example of perception from the famous dress image, prompting discussion of varied appearances in visual tasks.
Page 36: Appearance by Adjustment Task
Process whereby participants adjust colors to match perceived stimuli from instructional visuals.
Page 37: Measuring Appearance in Symmetric Tasks
Observing tilt conditions and participant perceptions in single-interval symmetric choice.
Page 38: Understanding the Psychometric Function and PSE
Point of Subjective Equality (PSE) defined as the level where distinct orientations cannot be determined.
Page 39: Challenges in Measurements Without Correct Answers
Sensitivity surrounding bias and participant responses in absence of definitive correct answers.
Page 40: Stimulus Manipulation Techniques
Focus on simultaneous and sequential presentations impacting perception changes.
Page 41: Tilt Illusion Example
Visual explanation of how surrounding stimuli can manipulate perceptions of other central stimuli.
Page 42: Tilt Illusion Measurement
Assessment of perceptions in presented conditions that alter central stripes orientation identification.
Page 43: Results from the Psychometric Function Analysis for Illusions
Notable shifts in PSE based on surrounding cue alignments.
Page 44: Course Segment Outline
Conclusion of part 4 quiz questions for assessment understanding so far.
Page 45: Overview of Stimulus Selection Methods
Recap of methods studied so far and introduction to key selection techniques in psychophysics.
Page 46: Method of Constant Stimuli
Fixed range of stimulus levels established prior to, measurement of responses by participants.
Page 47: Data Collection with Constant Stimuli
Observations from various levels allow threshold determination through comprehensive data fitting.
Page 48: Adaptive Methodologies
Procedures employed to refine estimations of thresholds through participant response modifications trial-by-trial.
Page 49: Adaptation Example in Staircase Methods
Description of approaches utilized to derive thresholds through flexible response dynamics.
Page 50: Method of Limits Exploration
Sequentially manipulating stimulus levels until detection confirmation is achieved, alternating between ascending and descending trials.
Page 51: Advantages of Method of Limits in Clinical Practice
Limited trials yield effectiveness, and importance in clinical applications (hearing tests, etc.).
Page 52: Method of Adjustment Effectiveness
Participant-driven adjustments ensuring efficiency, yet considerations over reliability and biases maintained.
Page 53: Comparison of Selection Methods
Evaluation of accuracy and speed between different stimulus selection methods presented in summary format.
Page 54: Analyzing Thresholds and PSEs
Different methods and approaches for determining psychometric functions, thresholds, or PSE estimations based on trial data.
Page 55: Statistical Analysis of Results
Definition on how to statistically validate observations derived from psychophysical measurements
Page 56: Closing Quiz
Assessment of knowledge consolidation in conclusion of course content.
Page 57: Summary of Psychophysics
Methods improving sensitivity measurement and the emphasis on physical properties and biases.
Establishment of the gold standard for accuracy through forced-choice methods while detailing participant dynamics in testing.
Techniques allow for clinical applications potential while maintaining attention and compliance methodologies.
Interaction results confirmed (F (1, 76) = 4.41, p = .04, 2 = .04).
No age differences for common words (small mean difference, overlapping CIs), but significant differences for rare words.
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Session Information (Repeats):
Aston University Birmingham
Join at: vevox.app ID: 187-498-854
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Understanding Interactions:
Interaction implies results in one condition are affected by another condition.
Interaction signifies that differences observed are not independent.
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Interpreting Interactions:
Combine post hoc tests, mean differences, and 95% CI analysis.
Example highlights no significant age difference for common words but a significant difference for rare words.
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Additional Example:
High and low anxiety participants administered different stimulants.
Galvanic skin response measured, leading to an interpretation of interaction effects.
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Interpretation of Example:
Interaction demonstrates that stimulant effects vary based on anxiety levels.
No significant differences observed without caffeine; differences emerge only with caffeine administration.
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Session Information (Repeats):
Aston University Birmingham
Join at: vevox.app ID: 187-498-854
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Interaction Interpretation Task:
Significant interaction across treatment groups (placebo, caffeine, amphetamine) in flanker conditions.
Need for interpretation of results.
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Another Interaction Example:
Analyzed interactions regarding animal types and sizes with corresponding confidence intervals.
Discussion on how to interpret results based on provided statistical output.
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Conclusion:
Encouragement for upcoming lectures covering mixed and repeated measures ANOVAs.