Stroop Effect - Experimental Research Methods - Lecture Slides, Slides of Research Methodology

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Stroop Effect

Brief Outline of the Introduction

• Define Interference
• Describe Stroop (as a task to measure interference)
  • Exp 1-little interference
  • Exp 2-lots of interference
  • Interference is funny
• Relative Speed of processing as an explanation for the interference seen in the Stroop effect (more details here) - Point out predicts fast read will interfere with slow color-naming, but the exact word does not matter
• Study where type of word does matter
• Final Paragraph

Stroop’s Second Experiment Task: Name Colors

Control Incongruent

Red

Blue

Green

Brown

Purple

Variants on the Stroop Effect

• Words “above”, “below”, “left” or “right” of a dot
• Name typefaces “bold”, “italics”, “underline”
• Sorting Tasks
• Picture naming tasks
• “Stroop Effect of words that differ from color words in one letter only”
• Pitch reporting

Explanations for the Stroop Effect Automaticity Theory

• All skills are learned to some degree of automaticity. - More automatic skills require less attentional resources.
• The processing of the color dimension requires much more attention than does processing of the reading dimension.

Explanations for the Stroop Effect Perceptual Encoding Theory

• Interference during encoding.
• The perceptual encoding of the ink color is slowed by incompatible information from the incongruent color word.

Is the Stroop Effect caused by Interference?

• The presence of the words interferes with the naming of the colors (or pictures or shapes). - However, the Stroop effect doesn‘t work in reverse - Words strongly related semantically to color (such as blood or sky) cause more interference than unrelated words. - Words high in emotional content produce more interference. docsity.com

Our Experiment Research Question

The relative speed of processing theory beautifully predicts the interference of (very fast) reading on our ability to perform a less well-learned (slower) skill. However, the theory does not predict that any one word is more interfering than another. We will test whether, contrary to the relative speed of processing theory, the semantic relatedness of the interfering words matters.

Our Experiment Possible Stimuli

Control Square Triangle Circle Rectangle Diamond

Incongruent Semantically Related

Square with “circle”

Triangle with “diamond”

Circle with “rectangle”

Rectangle with “square”

Diamond with “triangle”

Incongruent Semantically Unrelated

Square with “flower” Triangle with 7 letter word Circle with 9 letter word Rectangle with 6 letter word Diamond with 8 letter word

If the relative speed of processing explains the Stroop effect, what do the stimuli mean?

• Control = Time needed to name shapes; a pure measure of shape naming skills.
• ISR - Control = The interference that the presence of semantically related words has on shape naming skills; a reflection of Stroop’s second experiment.
• ISU - Control = The interference that the presence of semantically unrelated words has on shape naming skills; perhaps a true measure of the interference described by the relative speed of processing theory.
• ISR - ISU = Extent to which interference from semantically related words is stronger than interference from semantically unrelated words; if this number is anything other than zero, it is the amount to which the relative speed of processing theory falls short of predicting interference. docsity.com

Our Experiment Internal Validity Issues

• Must present all three lists to the same people because high amounts of individual variability necessitate that people act as controls for themselves.
• After naming shapes for a while, people will get better at the task. Therefore, we can not present the lists in the same order every time.
• If we only look at six responses from each condition, then a single bad response could drastically increase average time. - How many total trials should be used for an entire experiment? - We need multiples of 15

Our Experiment Internal Validity Issues

• If all lists present the shapes in the same order, people will remember the order.
• If we always present control in one order, then always present pictures in a second, then there could be something about one of the orderings that may be more memorable than another.
• Perhaps we should include practice trials that do not count.