Our paper “How animals discriminate between stimulus magnitudes: a meta-analysis” has been published in the journal Behavioral Ecology. This paper focusses on how animals, from worms to hummingbirds to primates, discriminate between signals and cues in the natural world. Such signals and cues can include the tail length of a prospective mate, the sweetness of sugary nectar, or the differences between a bird’s own eggs and those of its parasite (see the pages on our cuckoo finch and African cuckoo study systems for more on the latter!).
Often, as the magnitude of a stimulus increases, it becomes harder to detect small changes in this stimulus (termed the magnitude effect). This paper used a meta-analysis to investigate how commonly this effect applies across a range of species and stimuli. On average, there was indeed a magnitude effect (called ‘k’ in the image): animals tended to discriminate between stimuli based on the proportional difference between them, rather than the absolute difference (e.g. noticing that an object is 10% larger than another, regardless of whether that difference is 1cm or 100m). However, the strength of this effect varied a lot between species. The magnitude effect can affect animal decision-making and has interesting implications for the evolution of animal signals.
The paper was led by Megan Worsley, a Masters student at Imperial College London who was supervised by Tanmay Dixit.
You can read the full paper here: https://doi.org/10.1093/beheco/araf025
