The Importance of Ordinal Information in Interpreting Number/Letter Line Data.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human Behavior

Background:

• The mental number line (MNL) hypothesis posits a unique linear representation for numbers.
• Debate exists whether number-to-position (NP) tasks reflect an MNL or a more general ordered list representation.
• Strategic processes and generalized ordered list processing challenge the strict MNL hypothesis.

Purpose of the Study:

• To investigate whether number and letter position judgments rely on similar cognitive representations.
• To determine if deviations from linearity and response times differ between number and letter tasks.
• To test the MNL hypothesis against a more general ordered list processing account.

Main Methods:

• 84 participants completed number-to-position and alphabet-to-position tasks on horizontal lines.
• Judgments of linearity and response times were analyzed for number and letter stimuli.
• Tasks were presented on standard (left-to-right) and reverse (right-to-left) lines.

Main Results:

• Response times were slower for letters than numbers but not affected by line direction.
• Similar non-linear patterns in response times were observed for both number and letter stimuli.
• Judgment deviations from linearity were comparable across number and letter tasks.

Conclusions:

• Findings suggest a general mental representation underlies ordered list processing, not exclusive to numbers.
• A linear mental representation is not unique to numbers, supporting a broader cognitive account.
• The results align with the hypothesis that numbers utilize representations suited for general ordered sequence processing.