Cognitive biases are mental shortcuts that skew perception and decision-making. Product managers rely on data and user research to guide their choices, yet the brain processing that data comes preloaded with patterns that distort what it sees. At PR_D_CT DAY 2025 in Ghent, Servaas Strobbe (Head of Product at Tekst) mapped out five specific biases that hit product teams hardest and offered concrete tactics for each.
The talk is structured as a progressive reveal: five question marks on screen, each one uncovered as Servaas names the bias, illustrates it with product scenarios, and then shares how to overcome it. By the end, the final question mark turns into the word "Bias" itself, landing the meta-point that the biggest blind spot is not seeing your own blind spots.
Original Presentation Slides
Download the slides from this talk as presented at the gathering.
Confirmation Bias and Survivorship Bias
Confirmation bias is the tendency to interpret new evidence as confirmation of existing beliefs. In product work this shows up when teams run research that feels rigorous but actually just validates a decision already made. Servaas uses the classic 2-4-8 number sequence exercise to demonstrate how easily we lock onto a pattern and only test examples that confirm it.
