One of the very first key terms you are likely to have learnt in your study of psychology is ‘objective’ meaning based on observable, measurable data, free from personal bias. Many objective measures exist – time in seconds, weight in grams and our heart rate in beats per minute. However, you may have never stopped to question whether there are issues with the objectivity of ‘objective’ measures. In this Psychology in the News Issues and Debates special we consider how the Nomothetic vs Idiographic approach to investigation and the issue of Social Sensitivity can help us to explore real-world issues, in this case, Pulse oximeter studies.

A pulse oximeter works by shining red and infrared light through the finger to estimate oxygen saturation. The challenge for people with darker skin is that melanin — the pigment produced by melanocytes — may affect how light is absorbed and detected by the device, influencing the accuracy of readings. This means that oxygen saturation can appear within a normal range when it is in fact lower than the reading suggests.

As psychology students, we often learn that the nomothetic approach aims to produce objective, scientific knowledge through large-scale, quantitative research that can be generalised to wider populations. Pulse oximeter studies are a great example of this in action.

Recent meta-analyses (in 2024) combined data from tens of thousands of participants and found a consistent pattern: these devices tend to overestimate oxygen levels, particularly in individuals with high levels of skin pigmentation (e.g. darker skin tones), compared to those with low levels of skin pigmentation (e.g. lighter skin tones). This could lead to potential negative consequences if medical professionals are deciding about clinical intervention based on data which may not be accurate.

Importantly, this is also an example of socially sensitive research. According to Sieber and Stanley, such research carries both risks and benefits and that researchers should carefully consider the different aspects of their research project:

• The Research Question: The researcher must consider their research question carefully. Asking questions like ‘Are there racial differences in IQ?’ or ‘Is intelligence inherited?’ may be damaging to members of a particular group.
• The Methodology Used: The researcher needs to consider the treatment of the participants and their right to confidentiality and anonymity. For example, when research involves sensitive personal or health-related information.
• The Institutional Context: The researcher should be mindful of how the data is going to be used and consider who is funding the research. If the research is funded by a private institution or organisation, why are they funding the research and how do they intend to use the findings?
• Interpretation and Application of Findings: Finally, the researcher needs to consider how their findings might be interpreted and applied in the real-world. Could their data or results be used to inform policy?

This example highlights that even highly ‘objective’ measures can be influenced by underlying biases in technology and research design, suggesting that objectivity in science is not always absolute and that objective measures may not always be valid.

References:

Martin, D., Johns, C., Sorrell, L., Healy, E., Phull, M., Olusanya, S., Peters, M., & Fabes, J. (2024). Effect of skin tone on the accuracy of the estimation of arterial oxygen saturation by pulse oximetry: a systematic review. British journal of anaesthesia, 132(5), 945–956. https://doi.org/10.1016/j.bja....

ANSWER THE FOLLOWING QUESTIONS

1. Why do the meta-analyses into pulse oximeters represent a nomothetic approach to investigation?
2. Explain one strength and one weakness of taking a nomothetic approach in this area of study.
3. What is meant by ‘socially sensitive’ research?
4. Why is this area of study an example of socially sensitive research?
5. Sieber and Stanley make recommendations about how to carry out socially sensitive research. What would be the risks and benefits to research in this area?