# Effects of caffeine on temporal perception in Rattus norvegicus

## TL;DR

This study shows that caffeine can alter how rats perceive time, with certain doses making them think time is passing more slowly.

## Contribution

The study demonstrates that caffeine affects temporal perception in rats at specific doses, revealing a novel insight into its cognitive effects.

## Key findings

- Caffeine at 9.6 mg/kg increased the proportion of long response choices in both experiments.
- The 19.2 mg/kg dose also increased long response choices in Experiment 2.
- Higher doses of caffeine did not produce the same effect, and accuracy remained unaffected across all conditions.

## Abstract

We report two studies that tested the effects of caffeine, the world’s most widely used psychoactive drug, on temporal perception. We trained Wistar rats using the Bisection Procedure (Experiment 1) or the Stubbs’ Procedure (Experiment 2) to discriminate between short and long light stimuli. Once training finished, we administered caffeine orally (0, 9.6, and 96.0 mg/kg for Experiment 1 and 0, 9.6, 19.2, and 38.4 mg/kg for Experiment 2) 15 minutes prior to testing. Relative to the control condition, the 9.6 mg/kg condition (Experiments 1 and 2) and the 19.2 mg/kg condition (Experiment 2) resulted in an increase in proportion of choosing the long response. Meanwhile, overall accuracy was not affected by any condition in both experiments. Taken together, these results are consistent with the notion that caffeine, at some doses, speeds up temporal perception. However, it is not clear why the effect disappears at higher doses.