Hi everyone,
Recently came across the term *left-digit bias*, which seems to be attributed to researchers Manoj Thomas and Vicki Morowitz. I know it’s not new and thus might be obvious to those who have kept up with the research.
Could you please explain: What exactly does it mean? What are the major theories of how it functions/what triggers it in terms of perception and processing? Is it in any way associated with literacy or numeracy (i.e., is it weaker in right-to-left reading languages like Arabic or in people with stronger mathematical skills)?
Tried to read the OG papers. Not my domain, so I assume I’m grossly misunderstanding what it is and how it actually works. TIA!
Note: Reposted from the behavioral economics sub, thus the economics flair. Not sure if the same phenomenon exists under a different name in any other domains.
In: Economics
Left-digit bias is a phenomenon where you put more emphasis on the leftmost digit of a price. As an example, the actual difference between $10.00 and $9.99 is only one cent. However, with left-digit bias, you focus on the $10 and $9, ignoring the.99, and perceiving a greater difference in price than there actually is.
Why this bias exists is for the same reason all our other cognitive biases exist: we process information emotionally before we think about it rationally. And even then, our rational mind musters facts to create a *post hoc* justification for our emotional reaction.
It is the reason why most prices end in something like 99-cent.
People look at the left most digit in a number (wich using Arabic numerals have the highest value) to estimate the value of a number.
You may know intellectually that $39.99 is only a cent away from $40.00, but the difference feels much bigger intuitively.
It is not that people don’t know how big numbers are, but that they ave an intuitive understanding of numbers that makes them go by the first digit. Three is less than four so a number starting with 399 feels much less than one starting with 400, while two numbers like 432 and 433 fell more similar despite the pairs having the same difference between them.
It is also seen in how we put emphasis on being in our 30s and 40s when sorting people age wise despite a 39 and a 42 year old being close in age than a 38 and a 34 year old.
Monkey brains aren’t good at intuitively understanding numbers larger than the numbers of fingers they have.
When comparing numbers, especially prices, we tend to overvalue the first digit and undervalue the remainder. You’re likely to perceive a greater difference between $2,255 and $1,899 than between $1,899 and $1,255, because the latter are both “one thousand and something” and the former is “two thousand and something.”
Just to add on, Arabic still writes numbers the same way around, with the lowest digits on the right.
It’s related to another bias called “Anchoring.”
Anchoring is where the first number you hear sets your expectations. For example, if we’re negotiating a price for something, and the first suggested amount is $500, then it sets expectations that further suggestions should be around $500.
Since we read from left to right, Left-Digit bias works the same way. When reading the price “$4.99” we first read “$4” which anchors us to the price being around $4, before reading “.99.” This means the prices “$4.99″ vs.”$5.00” can feel closer to “$4.00” vs. “$5.00” even though the real prices are only 1 cent apart.
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