Critical thinkers: Microbiology and the scientific method

What is critical thinking? As with any oft-used term, and one centered on intellectual pursuits and of pedagogical research, there are differing approaches. One definition, which is useful, among the voluminous texts on the subject, is (1):

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“Critical thinking is the intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action.”

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Defining critical thinking is one thing. What makes for an effective ‘critical thinker’ is another (2).

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A good critical thinker is someone who can adapt to the situation and be able to appraise a situation and to ask searching questions for a topic, even if they are not the subject matter expert in that particular topic.

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And how does this apply to microbiology? How do we distil such concepts as objectivity, thoroughness and precision? So much of microbiology is based on examining unknowns or weighing up probability, to the extent that we need an understanding of uncertainty, especially in risk assessments (3).

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In this week’s article, we look at critical thinking, how this can apply to areas like pharmaceuticals and healthcare, and, because this is ‘Microbiology News’, draw briefly on some microbiological-related examples.

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Approaching critical thinking

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There are certain approaches that can be used with critical thinking, some more complex than others. One relatively straightforward approach is (4):

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• Identify the problem.
• Spend time thinking about the problem (often there will be clues to the solution within the problem itself) (5),
• Perform adequate research and gather data.
• Analyze and determine the relevance of gathered information.
• Ask relevant questions.
• Identify an effective solution.
• Present your solution.
• Analyze the solution's effectiveness.

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Characteristics of a critical thinker

There are certain characteristics that help one to develop as a critical thinker:

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1.????? Observational abilities and understanding the difference between observation and inference.

2.????? Questioning abilities, including an understanding of points of ambiguity and vagueness.

3.????? Inferential abilities including weighing up the difference between conclusive and defeasible inference.

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For example: We could observe that the grass in our local park is wet. There are several possible inferences: It may have rained, the park authorities may have used sprinklers, it could be morning dew, or a local river may have burst its bank.

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Training

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Training microbiologists at work to be effective critical thinkers is best approached using active learning strategies which means that trainees participate in their learning by discussing, writing about or solving problems. This is especially useful for homing in the skills necessary to take the microbiologist away from the lab bench and into the process area to tackle problems like contamination events. This approach is also important for developing laboratory skills, especially for method development.

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Useful training criteria include:

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Having trainees demonstrate an ability to formulate hypotheses and design experiments based on the scientific method.        

Showing the skills needed to analyze and interpret results from a variety of microbiological methods and apply these methods to similar situations.        

Showing mathematical reasoning and graphing skills to solve problems in microbiology.        

Practising how to communicate outcomes, especially to those unfamiliar with the field.        

Being able to identify credible scientific sources and interpret and evaluate information.        

Document and report using experimental protocols, results and conclusions; or with microbial investigation templates to conduct data deviation reviews.        

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Understanding the difference between necessary and sufficient conditions

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Sometimes we can narrow down the reasons for things by identifying what the necessary conditions are for something to occur. By this, a necessary condition is a condition that must be present for an event to occur. In contrast a sufficient condition is a condition that will actually produce the event. A necessary condition must be there, but by itself it does not provide sufficient cause for the occurrence of the event: something else needs to take place.

In risk assessment speak, this has parallels with ‘severity’ and ‘likelihood’,

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Experimental approaches

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Often assumptions need to be checked and here understanding of the concepts of hypothesis, null hypothesis, assumption, and prediction can be useful. This also extends to understanding the concept of statistical significance (and that ‘significance’ in this context is not the same as ‘importance’) (6).

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Accepting uncertainty

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Often things are not certain, or at least not immediately certain. Too often in areas like risk assessment, there is a level of ‘certainty’ imposed; either this is imposed too early or without due consideration of ‘fuzziness’.

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Fuzzy is not about the outcome of our critical thinking being fuzzy (as in erratic or error prone). Instead, it is a recognition of uncertainty.

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In science uncertainty is something that is part and parcel of research and inquiry – we learn something, we go back, we re-test and they may come to a different conclusion. At the end of the process there is the process of defuzzification, so we can reach a consensus.

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In relation to this is the useful mindset of being able to weigh up different arguments and to be abler to identify inconsistencies and errors in reasoning. For example:

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Noticing what implications there might be behind a proposal.        

Being able to wheedle out assumptions.        

Being prepared for counter-consideration (such as a post-change task) which might alter the initial conclusion.        

Approaching issues in a consistent way.        

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An effective critical thinker may not understand the subject fully, but they can ask pertinent questions. However, a degree of knowledge is equally important, and the level of knowledge required depends on the issue.

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Knowledge management

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Knowledge and the management of knowledge are important components of critical thinking. Knowledge is needed to input into solving a problem and, when the problem is solved, knowledge is an output (such as of what worked and what did not work). We should aim to capture this knowledge and disseminate it.

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Knowledge is a never-ending sequence of iterations. Knowledge is always there to be gained and ideally there is a feedback loop to other parts of the quality system (such as risk management and future process changes).

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Learning skills

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Being willing to learn and honing learning skills is useful. Being able to apply thought processes to different situations is also advantageous. For instance, critical thinking can be transferred to various situations, topics, and contexts – such as contamination investigations, root cause analysis, impact assessing change controls etc.

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Another important consideration is reflection: thinking about what has gone before and considering how to make it better next time.

How can we apply this thinking to pharmaceutical microbiology?

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There are many occasions where critical thinking is useful for microbiologists, especially where there remains the pressing need to leave the laboratory and go into the plant to assess contamination events.

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To take an example: If we are recertifying an autoclave and there is a biological indicator failure, then we have multiple factors and uncertainties: we have a nominal population and D-value for a BI (but we do not know how accurate this is); we have approximate load patterns; we may have precise temperature measurements, but we do not know precisely what the exact temperature that is needed to achieve the six-log reduction we are seeking – is it 121.0 degrees Celsius for 15 minutes or 121.2? Plus, there are many other factors to explore: air dryness, dry removal, the number of vacuum pulses, heat up times etc.

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Another example is with cleaning and disinfection, which is heavily operator dependent. Let’s say we see an increase in environmental monitoring counts. We may have a theoretical understanding that a certain disinfectant at a given concentration for a set contact time will kill a given population of non-resistant organisms, but there is fuzziness – what the human does, the situation, the equipment they have, how fatigued they are, whether this is the first cleanroom of the day they need to sanitize or the last, whether there are normally two operators who clean but today there is only one.

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This shows the value of understanding the situational context rather than a probabilistic one. The probabilistic approach might jump to decisions like ‘our bioburden may be higher so we need to double the disinfection’ or ‘logically there must be a more resistant microbe’.

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Critical thinking is also a necessary part of experimental design and the scientific method when designing experiments. If we want to kill a microorganism, what are factors that achieve kill? If we want to promote growth, what are the necessary prerequisites for enrichment? If we wish to preserve an organism so that its metabolic rate is reduced so that it will not express changes to its phenotype when we resuscitate it, how can this be achieved in a controlled manner?

Summary

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Critical thinking is a type of thinking that involves the use of analytical and evaluative cognitive processes. This includes analysis related to arguments based on logical consistency that aims to recognize bias and errors in reasoning. Such an approach is of benefit to many sectors, including pharmaceuticals and healthcare. Some applications have been explored, in relation to pharmaceutical microbiology.

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References

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1.????? University of Louisville, Delphi Center: https://louisville.edu/ideastoaction/about/criticalthinking/what#:~:text=Critical%20thinking%20is%20the%20intellectually,guide%20to%20belief%20and%20action.

2.????? Facione P A Sanchez C A Facione N C and Gainen J 1995 The disposition toward critical thinking. The Journal of General Education 44 1 pp.1-25

3.????? Gordon SP, Gross S, Bahamonde M, Winn J, Seifert J, Martin CA, Yang Y. 2022. Developing a mathematics curriculum for the biosciences. Primus 32:218–228

4.????? Cottrell S, 2017 Critical thinking skills: Effective analysis, argument and reflection. Macmillan International Higher Education

5.????? Ebomoyi JI. 2020. Metacognition and peer learning strategies as predictors in problem-solving performance in microbiology. J Microbiol Biol Educ 21:21.1.3

6.????? Colon-Berlingeri M, Burrowes PA. 2011. Teaching biology through statistics: application of statistical methods in genetics and zoology courses. CBE Life Sci Educ 10:259–267