Why We Can’t Stop Adding: New Research Examines “Additive Bias”

A new study led by researchers at the University of Cambridge and Suor Orsola Benincasa University (Naples) uncovers a cognitive bias that shapes much of our decision-making: the preference for adding rather than subtracting.

This bias influences decisions from personal choices to corporate strategies, suggesting that people naturally lean towards adding new elements rather than removing existing ones when faced with a problem.

The study was published in the Journal of Cognitive Psychology on May 20, 2024.

Methodology: Understanding the Bias

To explore this bias, the researchers designed a series of experiments using the additive bias Implicit Association Test (ad-IAT).

This tool measures participants’ automatic preferences for addition over subtraction.

Participants, recruited through Amazon Mechanical Turk, consisted of 126 native English speakers aged 18 and older, mostly from North America and Europe.

Experiment 1: Testing Preferences

In the first experiment, participants engaged in a task that involved categorizing words quickly.

These words were divided into two categories: addition-related words (e.g., “increase,” “augment,” “expand”) and subtraction-related words (e.g., “decrease,” “reduce,” “diminish”).

Participants also sorted words associated with positive attributes (e.g., “joyous,” “magnificent”) and negative attributes (e.g., “sad,” “horrible”).

The task was to pair addition words with positive attributes and subtraction words with negative attributes, and vice versa.

The speed and accuracy of their responses revealed a strong preference for associating addition with positive attributes.

Experiment 2: Multifaceted Insights

Building on the first experiment, the second explored different dimensions of the additive bias.

This time, participants categorized words along three dimensions: pleasant-unpleasant, functional-nonfunctional, and safe-unsafe.

For instance, they were asked to pair addition words with pleasant, functional, and safe words, and subtraction words with unpleasant, nonfunctional, and unsafe words.

The results showed that participants consistently viewed addition as not only pleasant but also more functional and safer compared to subtraction.

Experiment 3: Real-World Applications

The third experiment aimed to see if the ad-IAT could predict behavior in practical situations.

Participants were given a problem-solving task involving digital grid patterns.

The objective was to make the grid symmetrical using the fewest possible moves.

While subtracting elements was the more efficient solution, participants with a stronger bias towards addition, as indicated by their ad-IAT scores, tended to add more elements instead of removing them.

This experiment highlighted how the bias towards addition can lead to less efficient problem-solving strategies.

Implications and Insights

This preference for addition over subtraction is more than just a cognitive quirk; it has real-world implications.

The tendency to add can lead to unnecessarily complex solutions and missed opportunities for simplification.

In product design, this bias can result in “feature creep,” where unnecessary features are added, complicating the product without adding real value.

This bias also affects environmental sustainability.

Our inclination to accumulate and add more can lead to wastefulness and hinder efforts to adopt more sustainable practices that might involve reduction and simplification.

The study also suggests that this bias might be culturally ingrained.

From childhood, people are often rewarded for adding and building up rather than taking away, reinforcing the idea that more is better.

This cultural reinforcement might explain why the bias is so pervasive and difficult to overcome.

Concluding Thoughts

This research opens up new avenues for addressing this bias.

By recognizing and understanding our natural inclination towards addition, strategies can be developed to consciously consider subtraction as a viable, and often preferable, option.

“Overlooking subtraction,” the authors write, “may mean that people are missing out on opportunities to make their lives more fulfilling, their institutions more effective, and their planet more livable.”

Study Details:

• Title: “The Additive Bias: Investigating Preferences for Addition Over Subtraction”
• Journal: Journal of Cognitive Psychology
• Authors: Maria Adriana Neroni, Nathan Crilly, Maria Antonella Brandimonte
• Publication Date: May 20, 2024
• DOI: https://doi.org/10.1002/jocb.660