Effect of Prior Knowledge and Wisdom of Crowds Serial Order Memory Effect of Prior Knowledge and Wisdom of Crowds

Demonstrations Experiment 1 (Prior knowledge) http://madlab.ss.uci.edu/dem2/examples/ Experiment 2a (Serial Recall) study sequence of still images http://madlab.ss.uci.edu/memslides/ Experiment 2b (Serial Recall) study video http://madlab.ss.uci.edu/dem/

Research Goals Wisdom of crowds Analyze effect of prior knowledge Can we recover original sequence of events based on recollected order from a group of individuals? Models: Thurstonian model Perturbation model Analyze effect of prior knowledge How well can we order events a priori (i.e, without having even seen the original event sequence? How does our prior knowledge affect our episodic recall? Future goal incorporate effect of prior knowledge into wisdom of crowds analysis

Experiments Materials Experiment 1 (Prior knowledge) Type I: 3 videos with stereotyped event sequences (e.g. wedding) Type II: 3 videos with less predictable event sequence Extracted 10 images for testing Experiment 1 (Prior knowledge) 16 subjects No study sequence; main task is to order 10 images in as natural order as possible Experiment 2a (Serial Recall) 28 subjects Study video sequence followed by ordering task where subjects order 10 images as best as possible Experiment 2b (Serial Recall) in progress Same as Experiment 2a but now study sequence is a series of still images

Bus Sequence: Raw Data prior serial recall Note: first row is subject id, second row is Kendall tau to true ordering

Morning: Raw Data prior serial recall

Wedding: Raw Data prior serial recall

Yogurt: Raw Data prior serial recall

Pizza: Raw Data prior serial recall

Clay: Raw Data prior serial recall

Distribution of tau distances Type I (“informative prior”) Type 2 (“uninformative prior”) Note: bin width is two so first bar is the relative proportion to tau = 0 and tau = 1

E B C H F G A I J D 1 2 3 4 5 6 7 8 9 10 B A D C F E H G J I Prior Serial Recall 10% 30% 50% 70% 90% % of Participants Picking Position E B C H F G A I J D 1 2 3 4 5 6 7 8 9 10 B A D C F E H G J I

Median tau to truth Note: the mean tau expected for random sequences is 22.5 (=10*9/4)

Type I Type 2 Note: bin width is two so first bar is the relative proportion to tau = 0 and tau = 1

Wisdom of Crowds Analysis

Thurstonian Model

Thurstonian Model

Modified Perturbation Model Original order A B C D E F G H probability for individual j that the item at the source position i gets perturbed to the destination position k. D Recalled order Assumptions: individuals as well as items vary in perturbation noise levels

Modified Perturbation Model

Perturbation Model

Perturbation Model

Results

Overall Results t Mean