Have you ever stumbled across social media videos claiming that plants can hear? A recent one that I’ve seen suggested that country music stunts plant growth! Another Internet ‘scientist’ came up with an experiment allegedly showing that positive verbal affirmations enhance plant growth while verbally insulted plants ended up being stunted! While these experiments continue to rise in popularity, they are based on anecdotal evidence and hearsay that lacks replicability and controls, making them invalid from a scientific perspective. Despite the misinformation, plant scientists have genuinely been attempting to answer this age-old question. Even Charles Darwin set out to decipher this mystery by attempting to fold the leaves of a Mimosa pudica plant with his bassoon playing. Nearly 150 years later, we are still asking the same question, can plants hear? According to David Chamovitz in What a Plant Knows, we are yet to solve this mystery due to a historical barrier – poor experimental design.
Chamovitz recounts a particularly famous example of poor experimental design that resulted in mass public misinformation surrounding hearing in plants. Much like the social media plant experimenters, Dorothy Retallack used questionable methods to prove that rock music was harmful to plants, and by extension, to humans. To begin with, Retallack made the incorrect assumption that everything good or bad for a plant could be extrapolated to humans. This logic breaks down when obvious necessities are considered. For instance, fertilizer is beneficial for plants, but a human could die of nitrate poisoning by eating fertilizer pellets.
Continuing with her fantasy, Retallack exposed plants to the classical tunes of Bach and Schoenberg versus the rock-and-roll hall of fame stars, Jimi Hendrix and Led Zeppelin. Surprisingly, Dorothy found that plant growth was only stunted from rock music and not from classical music. Hold up, not so fast! Chamovitz argues that Dorothy used too small a sample size for her final conclusions as most test groups consisted of fewer than five replicates. Additionally, Chamovitz argues that there were underlying experimental biases as Dorothy conducted her experiments in multiple locations in varying light, temperature, and humidity regimes. Finally, the controlled variables were not properly monitored and “soil moisture” was measured by the touch of a finger instead of quantitative criteria. So, was rock music harmful to Dorothy’s plants? Maybe. However, neither her experiment nor any subsequent experiments have been able to demonstrate this. As a result, there is no scientific basis for such a claim. As fascinating as the idea of music genres causing differing effects on plant health and growth sounds, there is simply no ecological relevance for music playing any role in plant survival and reproduction. Critically ask why plants would ever need to evolve a response to human music? The question of whether plants have a preference for certain tunes is a nonsensical one.
However, this does not rule out the possibility of other forms of hearing. Recent cutting-edge plant research such as a study by Mishra et al. (2016) suggests that there are a few important sounds that would benefit a plant to hear, such as the sound of running water or pollinating bees. So, while it seems that plants cannot hear, this conclusion could easily change with new research. A more convincing form of hearing is a plant’s response to buzz pollination. A recent study has shown that the sound of a pollinator’s buzz induces physiological changes in some species of plants. While many would argue this is a vibration-detection response and therefore touch, this distinction is a philosophical one. Moving forward, Chamovitz urges folks to avoid attributing human characteristics onto plants and to recognize the unique adaptations of plants in their own right.