We read with interest the article on cognitive errors in clinical
reasoning by Ian Scott (1) and we agree that a greater awareness of the
causes would help clinicians to avoid many of them. However, we feel that
more caution should be taken when placing the important category of
heuristics, together with other hindsight and affective errors.
Heuristic
is a term originally derived from the Greek "heurisko" (the verb from
which Archimedes's famous exclamation of "eureka" was derived), which
roughly means “discover”. It is only after 1970 that a negative meaning of
the term emerged in the fields of cognitive psychology and decision-making
research: fast decision-making method(s) that people often misapply to
situations where probability theory should be applied instead. Ever since,
the term appears in medical literature with this later meaning apart some
rare exceptions. Even though the author does refer to one of these rare
exceptions (“box 2”) we feel that he did not apply the appropriate caution
when making suggestions about strategies against heuristic thinking.
The
author seems to follow the belief of most authors of medical educational
articles on heuristics that by stepping-up the probabilistic teaching will
cause heuristic thinking to “melt into” probabilistic thinking. Although
this seems a truism is not necessarily true. Even though the probabilistic
tools have been available for centuries and in the last three decades they
have been applied increasingly to medical problems (in medical school
curricula, journal articles, and postgraduate education programs), their
application has not filtered down to affect the heuristic thinking of most
experienced clinicians. The same is true for medical students. The results
of a study that we undertook recently (unpublished data) show that even
when every data necessary in decision-making according to probability
theory is available, most students (80%) bypass it because their thought
does not work on probabilistic grounds but on heuristics grounds. Other
studies on non-medical students have yielded similar results. This
suggests that heuristics are established as capital cognitive problem-
solving mechanisms at an early phase of cognitive development, at pre-university years. Indeed, several studies with school pupils (2) have
concluded that heuristics coincide with the emergence of formal reasoning
(about age 12), and, most important, tend to stabilize and become
resistant to the influence of age and instruction (3).
How can this strong adherence to heuristics in almost every
educational and professional level be explained? Certain modern cognitive scientists
see heuristics as adaptive “inherent” tools - constructed by natural
selection over many thousands of years of evolutionary time – useful in
our daily interactions with an ever changing environment where fast
decisions must be made while only a limited set of parameters - needed for
making a probabilistic decision - are known or can be processed. Under
this perspective heuristics are considered most useful and not just
misconceptions of probability theory. Recent cognitive studies have
actually shown that sometimes heuristics can yield better outcomes than
probabilistic reasoning (4,5). The availability heuristic can result to a
creative action while the representativeness heuristic although may have
many negative consequences, not the least of which is causing patients
undue worry, may be justified in erring on the safe side when consequences
of a missed diagnosis are dire for the patient. For these reasons, there
is a growing opinion among cognitive scientists that heuristics are not
just setbacks of progress in Evidence Based Medicine (EBM) but successful
tools in medical decision-making that should be embraced rather overcome
(6). Probabilistic and heuristic reasoning share a common problem-solving
orientation but are based on two distinct mental schemas with different
functions. The laws of probability are primarily concerned with the
internal logic coherence of judgments. On the contrary, the function of
heuristics is not to be coherent but rather to make adaptive inferences
about the real social and physical world given limited time and knowledge.
The above raise a fundamental issue about the nature of the learner’s
cognitive context prior to the medical teacher’s intervention. Does a
medical educator by discouraging heuristics overtly discourage the very
essence of adaptive human reasoning, and teach a style of information
processing which is unrealistic for dealing with the real world? This
problem should not be ignored when making proposals about teaching methods
and materials. We feel that the specific question has not yet been
answered. The cognitive aspects of the concept of probability seem to be
much more complex than it is usually considered and in medical teaching
area there has been insufficient synthesis of pedagogical ideas with
modern cognitive theories. New teaching models are needed in order to
clarify how we can combine (and not eradicate) heuristic-adaptive thinking
with probability theory and EBM. No harsh dividing line would be
recognized between them; heuristic and probabilistic thinking are the two
sides of the same coin. Ultimately, such a unified approach could yield a
more rational background for research in this field that could be more
useful to, and more reliably applied by, the medical teacher.
REFERENCES
1. Ian A. Scott. Errors in clinical reasoning: causes and remedial
strategies. BMJ 2009;338:b1860.
2. Fischbein E., Schnarch D. The evolution with age of probabilistic,
intuitively based misconceptions. Journal of research in Mathematics
Education 1997; 28(1):96-105.
3. Fischbein E., Gazit A. Does the Teaching of Probability Improve
Probabilistic Intuitions?: An Exploratory Research Study. Educational
Studies in Mathematics 1984; 15(1):1-24.
4. Gigerenzer G., Todd P.M. and the ABC Research Group. Simple heuristics
that make us smart. Oxford UP. Oxford. 1999.
5. Gigernzer G. Gut feelings: the intelligence of the unconscious. Viking
Books. New York. 2007.
6. Eva K.W., Norman G.R. Heuristics and biases – a biased perspective on
clinical reasoning. Medical Education 2005; 39:870-872.
Competing interests:
None declared
Competing interests:
No competing interests
10 June 2009
Haralampos V. Harissis
Assistant Professor of Surgery
Haralampos Batsis, Christos Katsios
Univesity of Ioannina, Medical School. University Hospital of Ioannina, St. Niarchou Av., Ioannina
Rapid Response:
Heuristics and evidence: there is room for both
We read with interest the article on cognitive errors in clinical
reasoning by Ian Scott (1) and we agree that a greater awareness of the
causes would help clinicians to avoid many of them. However, we feel that
more caution should be taken when placing the important category of
heuristics, together with other hindsight and affective errors.
Heuristic
is a term originally derived from the Greek "heurisko" (the verb from
which Archimedes's famous exclamation of "eureka" was derived), which
roughly means “discover”. It is only after 1970 that a negative meaning of
the term emerged in the fields of cognitive psychology and decision-making
research: fast decision-making method(s) that people often misapply to
situations where probability theory should be applied instead. Ever since,
the term appears in medical literature with this later meaning apart some
rare exceptions. Even though the author does refer to one of these rare
exceptions (“box 2”) we feel that he did not apply the appropriate caution
when making suggestions about strategies against heuristic thinking.
The
author seems to follow the belief of most authors of medical educational
articles on heuristics that by stepping-up the probabilistic teaching will
cause heuristic thinking to “melt into” probabilistic thinking. Although
this seems a truism is not necessarily true. Even though the probabilistic
tools have been available for centuries and in the last three decades they
have been applied increasingly to medical problems (in medical school
curricula, journal articles, and postgraduate education programs), their
application has not filtered down to affect the heuristic thinking of most
experienced clinicians. The same is true for medical students. The results
of a study that we undertook recently (unpublished data) show that even
when every data necessary in decision-making according to probability
theory is available, most students (80%) bypass it because their thought
does not work on probabilistic grounds but on heuristics grounds. Other
studies on non-medical students have yielded similar results. This
suggests that heuristics are established as capital cognitive problem-
solving mechanisms at an early phase of cognitive development, at pre-university years. Indeed, several studies with school pupils (2) have
concluded that heuristics coincide with the emergence of formal reasoning
(about age 12), and, most important, tend to stabilize and become
resistant to the influence of age and instruction (3).
How can this strong adherence to heuristics in almost every
educational and professional level be explained? Certain modern cognitive scientists
see heuristics as adaptive “inherent” tools - constructed by natural
selection over many thousands of years of evolutionary time – useful in
our daily interactions with an ever changing environment where fast
decisions must be made while only a limited set of parameters - needed for
making a probabilistic decision - are known or can be processed. Under
this perspective heuristics are considered most useful and not just
misconceptions of probability theory. Recent cognitive studies have
actually shown that sometimes heuristics can yield better outcomes than
probabilistic reasoning (4,5). The availability heuristic can result to a
creative action while the representativeness heuristic although may have
many negative consequences, not the least of which is causing patients
undue worry, may be justified in erring on the safe side when consequences
of a missed diagnosis are dire for the patient. For these reasons, there
is a growing opinion among cognitive scientists that heuristics are not
just setbacks of progress in Evidence Based Medicine (EBM) but successful
tools in medical decision-making that should be embraced rather overcome
(6). Probabilistic and heuristic reasoning share a common problem-solving
orientation but are based on two distinct mental schemas with different
functions. The laws of probability are primarily concerned with the
internal logic coherence of judgments. On the contrary, the function of
heuristics is not to be coherent but rather to make adaptive inferences
about the real social and physical world given limited time and knowledge.
The above raise a fundamental issue about the nature of the learner’s
cognitive context prior to the medical teacher’s intervention. Does a
medical educator by discouraging heuristics overtly discourage the very
essence of adaptive human reasoning, and teach a style of information
processing which is unrealistic for dealing with the real world? This
problem should not be ignored when making proposals about teaching methods
and materials. We feel that the specific question has not yet been
answered. The cognitive aspects of the concept of probability seem to be
much more complex than it is usually considered and in medical teaching
area there has been insufficient synthesis of pedagogical ideas with
modern cognitive theories. New teaching models are needed in order to
clarify how we can combine (and not eradicate) heuristic-adaptive thinking
with probability theory and EBM. No harsh dividing line would be
recognized between them; heuristic and probabilistic thinking are the two
sides of the same coin. Ultimately, such a unified approach could yield a
more rational background for research in this field that could be more
useful to, and more reliably applied by, the medical teacher.
REFERENCES
1. Ian A. Scott. Errors in clinical reasoning: causes and remedial
strategies. BMJ 2009;338:b1860.
2. Fischbein E., Schnarch D. The evolution with age of probabilistic,
intuitively based misconceptions. Journal of research in Mathematics
Education 1997; 28(1):96-105.
3. Fischbein E., Gazit A. Does the Teaching of Probability Improve
Probabilistic Intuitions?: An Exploratory Research Study. Educational
Studies in Mathematics 1984; 15(1):1-24.
4. Gigerenzer G., Todd P.M. and the ABC Research Group. Simple heuristics
that make us smart. Oxford UP. Oxford. 1999.
5. Gigernzer G. Gut feelings: the intelligence of the unconscious. Viking
Books. New York. 2007.
6. Eva K.W., Norman G.R. Heuristics and biases – a biased perspective on
clinical reasoning. Medical Education 2005; 39:870-872.
Competing interests:
None declared
Competing interests: No competing interests