Do you believe in ghosts? An article in the Guardian reporting on some recently published research suggests that ‘spooky feelings’ may have a scientific explanation.

The key concept in this research is infrasound, which refers to sound waves with a frequency below 20 Hz. These are frequencies which humans cannot consciously hear, but they are present in many environments we spend time in, such as older buildings. For example, they can be produced by very old boilers or ventilation systems. Whilst we are not aware of the sounds, there is some evidence that our bodies might still respond to them.

In the experiment, 36 participants were exposed to either calming or unsettling music, with infrasound either present or absent. The study took place in a highly controlled environment. This created what is called a 2 x 2 independent measures design, which allowed researchers to investigate the effect of the type of music and the presence of infrasound. Participants self-reported their mood after the exposure, and researchers also collected saliva samples to measure cortisol levels (a hormone linked to stress).

Findings indicated that the participants were unable to consciously detect the infrasound. However, those exposed to infrasound showed statistically significantly higher levels of cortisol, indicating increased stress. In addition, they also reported feeling more irritable and sadder compared to those not exposed to infrasound.

Speaking about the findings, one of the researchers said, “In plain terms, you cannot hear infrasound, but your body and your mood appear to respond to it anyway, and the response tends to be unpleasant.”

Whilst further research with larger samples is needed, this research gives us an interesting scientific explanation for why some environments may make us feel unsettled.

References:

Spooky feelings in old houses may be caused by boiler sounds, study suggests https://www.theguardian.com/sc... (accessed 29.4.26)

Scatterty KR, VonStein D, Prichard LB, Franczak BC, Hamilton TJ and Schmaltz RM (2026) Infrasound exposure is linked to aversive responding, negative appraisal, and elevated salivary cortisol in humans. Front. Behav. Neurosci. 20:1729876. doi: 10.3389/fnbeh.2026.1729876

ANSWER THE FOLLOWING QUESTIONS!

1. What experimental method was used in this study? Justify your answer.
2. This experiment uses something you may not have come across before called a 2 x 2 design. This is when there are two independent variables (IVs), and each IV has two levels (conditions). Outline each of the IVs in this experiment.
3. Outline one issue with the validity of this study.
4. For the issue you have outlined above, explain one way in which you would try to improve the validity of this study.
5. Did this research use primary or secondary data? Justify your answer with reference to this study.