Fish are flexible learners who can discriminate human faces

Abstract

In his book " What a fish knows " Jonathan Balcombe (2016a, b) has created a comprehensive profile of a group of animals still often thought to have a 3-second memory, no ability to feel pain, and a generally limited ability to learn. Chapter by chapter, Balcombe dismantles these and other such assumptions and makes a convincing case that fish have many abilities that are not that different from our own. Here, I focus on one example which supports the notion that fish are flexible learners and able to perform tasks which are generally thought to require the advanced processing power of the primate cortex. Archerfish and damselfish are able to discriminate human faces, even when the faces are partly obscured by artificial noise, rotated or presented as standardised greyscale images. This demonstrates that the machinery for the visual analysis and processing of objects is present in fish and leads to the question of why this machinery was transferred to the cortex in primates.