The shirt reads: “WHY WAS PAVLOV’S HAIR SO SOFT? BECAUSE HE CONDITIONED IT.”
Between the lines, a portrait of a bearded nineteenth-century scientist with his hand at his chin, drawn in black and white engraving style.
Classical conditioning and hair conditioner, one word doing both. It is the most reliable joke in first-year psychology and it has survived being told several million times.
For psychology students, lecturers, and anyone who has sat through the lecture where this is guaranteed to come up.
