# Rats can distinguish (and generalize) among two white wine varieties

## TL;DR

Rats can learn to distinguish and generalize between two types of white wine, challenging the idea that humans are uniquely good at such tasks due to language and cognition.

## Contribution

This study shows that rats can generalize complex olfactory categories without relying on language or human-specific cognitive abilities.

## Key findings

- All nine rats successfully learned to discriminate between Riesling and Sauvignon Blanc wines.
- Most rats generalized the discrimination to novel wines of the same varieties within two test trials.
- The results suggest non-human animals can form olfactory categories without linguistic or conceptual frameworks.

## Abstract

In the olfactory literature there is considerable debate about how differences in olfactory receptors across different species map onto variations in perceptual acuity and performance. Although humans have fewer functional olfactory receptors than most other mammals, it has been suggested that linguistic and cognitive abilities help compensate for this apparent deficit and enhance discriminative abilities, particularly through humans’ ability to categorize sensory stimuli into conceptual categories. However, previous research suggests that non-human animals can learn complex categories, involving multiple perceptual dimensions, indicating that they can discriminate complex odor stimuli without language. We investigated generalization over complex olfactory categories by examining rats' discrimination of wine varieties, a challenging task for humans that has been suggested to rely heavily on human-specific linguistic, cognitive and categorization abilities. Nine rats were trained in an olfactory discrimination task (go/no-go) using a specific wine variety (Riesling or Sauvignon Blanc from different winemakers) as the S + . Rats were then tested using novel wines of the same varieties in unrewarded probe trials to assess their abilities to correctly assign instances of wine to specific categories. Interestingly, all nine rats successfully learned to discriminate the two varieties, and most rats generalized within two test trials to novel wines of the same varieties. We explore the implications of our results for olfactory concept formation and categorization more generally.

The online version contains supplementary material available at 10.1007/s10071-025-01937-2.