What is Functional Fixedness?


Functional fixedness is a cognitive bias that limits a person to use an object only in the way it is traditionally used.

The concept of functional fixedness originated in Gestalt psychology, a movement in psychology that emphasizes holistic processing. Karl Duncker defined functional fixedness as being a mental block against using an object in a new way that is required to solve a problem. This “block” limits the ability of an individual to use components given to them to complete a task, as they cannot move past the original purpose of those components. For example, if someone needs a paperweight, but they only have a hammer, they may not see how the hammer can be used as a paperweight. Functional fixedness is this inability to see a hammer’s use as anything other than for pounding nails; the person couldn’t think to use the hammer in a way other than in its conventional function.

When tested, 5-year-old children show no signs of functional fixedness. It has been argued that this is because at age 5, any goal to be achieved with an object is equivalent to any other goal. However, by age 7, children have acquired the tendency to treat the originally intended purpose of an object as special.

Examples in Research

Experimental paradigms typically involve solving problems in novel situations in which the subject has the use of a familiar object in an unfamiliar context. The object may be familiar from the subject’s past experience or from previous tasks within an experiment.

Candle Box

In a classic experiment demonstrating functional fixedness, Duncker (1945) gave participants a candle, a box of thumbtacks, and a book of matches, and asked them to attach the candle to the wall so that it did not drip onto the table below. Duncker found that participants tried to attach the candle directly to the wall with the tacks, or to glue it to the wall by melting it. Very few of them thought of using the inside of the box as a candle-holder and tacking this to the wall. In Duncker’s terms, the participants were “fixated” on the box’s normal function of holding thumbtacks and could not re-conceptualize it in a manner that allowed them to solve the problem. For instance, participants presented with an empty tack box were two times more likely to solve the problem than those presented with the tack box used as a container.

Candle box problem diagram.

More recently, Frank and Ramscar (2003) gave a written version of the candle problem to undergraduates at Stanford University. When the problem was given with identical instructions to those in the original experiment, only 23% of the students were able to solve the problem. For another group of students, the noun phrases such as “box of matches” were underlined, and for a third group, the nouns (e.g. “box”) were underlined. For these two groups, 55% and 47% were able to solve the problem effectively. In a follow-up experiment, all the nouns except “box” were underlined and similar results were produced. The authors concluded that students’ performance was contingent on their representation of the lexical concept “box” rather than instructional manipulations. The ability to overcome functional fixedness was contingent on having a flexible representation of the word box which allows students to see that the box can be used when attaching a candle to a wall.

When Adamson (1952) replicated Duncker’s box experiment, Adamson split participants into 2 experimental groups:

  • Preutilisation; and
  • No preutilisation.

In this experiment, when there is preutilisation, meaning when objects are presented to participants in a traditional manner (materials are in the box, thus using the box as a container), participants are less likely to consider the box for any other use, whereas with no preutilisation (when boxes are presented empty), participants are more likely to think of other uses for the box.

The Two-Cords Problem

Birch and Rabinowitz (1951) adapted the two-cord problem from Norman Maier (1930, 1931), where subjects would be given 2 cords hanging from the ceiling, and 2 heavy objects in the room. They are told they must connect the cords, but they are just far enough apart that one cannot reach the other easily. The solution was to tie one of the heavy objects to a cord and be a weight, and swing the cord as a pendulum, catch the rope as it swings while holding on to the other rope, and then tie them together. The participants are split into 3 groups: Group R, which completes a pre-task of completing an electrical circuit by using a relay, Group S, which completes the circuit with a switch, and Group C which is the control group given no pre-test experience. Group R participants were more likely to use the switch as the weight, and Group S were more likely to use the relay. Both groups did so because their previous experience led them to use the objects a certain way, and functional fixedness did not allow them to see the objects as being used for another purpose.

Barometer Question

The barometer question is an example of an incorrectly designed examination question demonstrating functional fixedness that causes a moral dilemma for the examinator. In its classic form, popularized by American test designer professor Alexander Calandra (1911-2006), the question asked the student to “show how it is possible to determine the height of a tall building with the aid of a barometer?” The examinator was confident that there was one, and only one, correct answer. Contrary to the examinator’s expectations, the student responded with a series of completely different answers. These answers were also correct, yet none of them proved the student’s competence in the specific academic field being tested.

Calandra presented the incident as a real-life, first-person experience that occurred during the Sputnik crisis. Calandra’s essay, “Angels on a Pin”, was published in 1959 in Pride, a magazine of the American College Public Relations Association. It was reprinted in Current Science in 1964, reprinted again in Saturday Review in 1968, and included in the 1969 edition of Calandra’s The Teaching of Elementary Science and Mathematics. In the same year (1969), Calandra’s essay became a subject of an academic discussion. The essay has been referenced frequently since, making its way into books on subjects ranging from teaching, writing skills, workplace counselling, and investment in real estate to chemical industry, computer programming, and integrated circuit design.

Current Conceptual Relevance

Is Functional Fixedness Universal?

Researchers have investigated whether functional fixedness is affected by culture.

In a recent study, preliminary evidence supporting the universality of functional fixedness was found. The study’s purpose was to test if individuals from non-industrialized societies, specifically with low exposure to “high-tech” artefacts, demonstrated functional fixedness. The study tested the Shuar, hunter-horticulturalists of the Amazon region of Ecuador, and compared them to a control group from an industrial culture.

The Shuar community had only been exposed to a limited amount of industrialised artefacts, such as machete, axes, cooking pots, nails, shotguns, and fishhooks, all considered “low-tech”. Two tasks were assessed to participants for the study: the box task, where participants had to build a tower to help a character from a fictional storyline to reach another character with a limited set of varied materials; the spoon task, where participants were also given a problem to solve based on a fictional story of a rabbit that had to cross a river (materials were used to represent settings) and they were given varied materials including a spoon. In the box-task, participants were slower to select the materials than participants in control conditions, but no difference in time to solve the problem was seen. In the spoon task, participants were slower in selection and completion of task. Results showed that Individuals from non-industrial (“technologically sparse cultures”) were susceptible to functional fixedness. They were faster to use artefacts without priming than when design function was explained to them. This occurred even though participants were less exposed to industrialised manufactured artefacts, and that the few artefacts they currently use were used in multiple ways regardless of their design.

“Following the Wrong Footsteps: Fixation Effects of Pictorial Examples in a Design Problem-Solving Task”

Investigators examined in two experiments “whether the inclusion of examples with inappropriate elements, in addition to the instructions for a design problem, would produce fixation effects in students naive to design tasks”. They examined the inclusion of examples of inappropriate elements, by explicitly depicting problematic aspects of the problem presented to the students through example designs. They tested non-expert participants on three problem conditions: with standard instruction, fixated (with inclusion of problematic design), and defixated (inclusion of problematic design accompanied with helpful methods). They were able to support their hypothesis by finding that:

  1. Problematic design examples produce significant fixation effects; and
  2. Fixation effects can be diminished with the use of defixating instructions.

In “The Disposable Spill-Proof Coffee Cup Problem”, adapted from Janson & Smith, 1991, participants were asked to construct as many designs as possible for an inexpensive, disposable, spill-proof coffee cup. Standard condition participants were presented only with instructions. In the fixated condition, participants were presented with instructions, a design, and problems they should be aware of. Finally, in the defixated condition, participants were presented the same as other conditions in addition to suggestions of design elements they should avoid using. The other two problems included building a bike rack, and designing a container for cream cheese.

Techniques to Avoid Functional Fixedness

Overcoming Functional Fixedness in Science Classrooms with Analogical Transfer

Based on the assumption that students are functionally fixed, a study on analogical transfer in the science classroom shed light on significant data that could provide an overcoming technique for functional fixedness. The findings support the fact that students show positive transfer (performance) on problem solving after being presented with analogies of certain structure and format. The present study expanded Duncker’s experiments from 1945 by trying to demonstrate that when students were “presented with a single analogy formatted as a problem, rather than as a story narrative, they would orient the task of problem-solving and facilitate positive transfer”.

A total of 266 freshmen students from a high school science class participated in the study. The experiment was a 2×2 design where conditions: “task contexts” (type and format) vs. “prior knowledge” (specific vs. general) were attested. Students were classified into 5 different groups, where 4 were according to their prior science knowledge (ranging from specific to general), and 1 served as a control group (no analogue presentation). The 4 different groups were then classified into “analogue type and analogue format” conditions, structural or surface types and problem or surface formats.

Inconclusive evidence was found for positive analogical transfer based on prior knowledge; however, groups did demonstrate variability. The problem format and the structural type of analogue presentation showed the highest positive transference to problem solving. The researcher suggested that a well-thought and planned analogy relevant in format and type to the problem-solving task to be completed can be helpful for students to overcome functional fixedness. This study not only brought new knowledge about the human mind at work but also provides important tools for educational purposes and possible changes that teachers can apply as aids to lesson plans.


One study suggests that functional fixedness can be combated by design decisions from functionally fixed designs so that the essence of the design is kept (Latour, 1994). This helps the subjects who have created functionally fixed designs understand how to go about solving general problems of this type, rather than using the fixed solution for a specific problem. Latour performed an experiment researching this by having software engineers analyse a fairly standard bit of code – the quicksort algorithm – and use it to create a partitioning function. Part of the quicksort algorithm involves partitioning a list into subsets so that it can be sorted; the experimenters wanted to use the code from within the algorithm to just do the partitioning. To do this, they abstracted each block of code in the function, discerning the purpose of it, and deciding if it is needed for the partitioning algorithm. This abstracting allowed them to reuse the code from the quicksort algorithm to create a working partition algorithm without having to design it from scratch.

Overcoming Prototypes

A comprehensive study exploring several classical functional fixedness experiments showed an overlying theme of overcoming prototypes. Those that were successful at completing the tasks had the ability to look beyond the prototype, or the original intention for the item in use. Conversely, those that could not create a successful finished product could not move beyond the original use of the item. This seemed to be the case for functional fixedness categorisation studies as well. Reorganisation into categories of seemingly unrelated items was easier for those that could look beyond intended function. Therefore, there is a need to overcome the prototype in order to avoid functional fixedness. Carnevale (1998) suggests analysing the object and mentally breaking it down into its components. After that is completed, it is essential to explore the possible functions of those parts. In doing so, an individual may familiarise themselves with new ways to use the items that are available to them at the givens. Individuals are therefore thinking creatively and overcoming the prototypes that limit their ability to successfully complete the functional fixedness problem.

The Generic Parts Technique

For each object, you need to decouple its function from its form. McCaffrey (2012) shows a highly effective technique for doing so. As you break an object into its parts, ask yourself two questions. “Can I subdivide the current part further?” If yes, do so. “Does my current description imply a use?” If yes, create a more generic description involving its shape and material. For example, initially I divide a candle into its parts: wick and wax. The word “wick” implies a use: burning to emit light. So, describe it more generically as a string. Since “string” implies a use, I describe it more generically: interwoven fibrous strands. This brings to mind that I could use the wick to make a wig for my hamster. Since “interwoven fibrous strands” does not imply a use, I can stop working on wick and start working on wax. People trained in this technique solved 67% more problems that suffered from functional fixedness than a control group. This technique systematically strips away all the layers of associated uses from an object and its parts.

What is Depressive Realism?


Depressive realism is the hypothesis developed by Lauren Alloy and Lyn Yvonne Abramson that depressed individuals make more realistic inferences than non-depressed individuals.

Although depressed individuals are thought to have a negative cognitive bias that results in recurrent, negative automatic thoughts, maladaptive behaviours, and dysfunctional world beliefs, depressive realism argues not only that this negativity may reflect a more accurate appraisal of the world but also that non-depressed individuals’ appraisals are positively biased.

Refer to Defensive Pessimism.

Evidence (For)

When participants were asked to press a button and rate the control they perceived they had over whether or not a light turned on, depressed individuals made more accurate ratings of control than non-depressed individuals. Among participants asked to complete a task and rate their performance without any feedback, depressed individuals made more accurate self-ratings than non-depressed individuals. For participants asked to complete a series of tasks, given feedback on their performance after each task, and who self-rated their overall performance after completing all the tasks, depressed individuals were again more likely to give an accurate self-rating than non-depressed individuals. When asked to evaluate their performance both immediately and some time after completing a task, depressed individuals made accurate appraisals both immediately before and after time had passed.

In a functional magnetic resonance imaging (fMRI) study of the brain, depressed patients were shown to be more accurate in their causal attributions of positive and negative social events than non-depressed participants, who demonstrated a positive bias. This difference was also reflected in the differential activation of the fronto-temporal network, higher activation for non self-serving attributions in non-depressed participants and for self-serving attributions in depressed patients, and reduced coupling of the dorsomedial prefrontal cortex seed region and the limbic areas when depressed patients made self-serving attributions.

Evidence (Against)

When asked to rate both their performance and the performance of others, non-depressed individuals demonstrated positive bias when rating themselves but no bias when rating others. Depressed individuals conversely showed no bias when rating themselves but a positive bias when rating others.

When assessing participant thoughts in public versus private settings, the thoughts of non-depressed individuals were more optimistic in public than private, while depressed individuals were less optimistic in public.

When asked to rate their performance immediately after a task and after some time had passed, depressed individuals were more accurate when they rated themselves immediately after the task but were more negative after time had passed whereas non-depressed individuals were positive immediately after and some time after.

Although depressed individuals make accurate judgments about having no control in situations where they in fact have no control, this appraisal also carries over to situations where they do have control, suggesting that the depressed perspective is not more accurate overall. Note, however, that this finding alone does not imply depression as a cause; researchers did not control for philosophical factors such as determinism which could affect responses.

One study suggested that in real-world settings, depressed individuals are actually less accurate and more overconfident in their predictions than their non-depressed peers. Participants’ attributional accuracy may also be more related to their overall attributional style rather than the presence and severity of their depressive symptoms.

Criticism of the Evidence

Some have argued that the evidence is not more conclusive because no standard for reality exists, the diagnoses are dubious, and the results may not apply to the real world. Because many studies rely on self-report of depressive symptoms and self-reports are known to be biased, the diagnosis of depression in these studies may not be valid, necessitating the use of other objective measures. Due to most of these studies using designs that do not necessarily approximate real-world phenomena, the external validity of the depressive realism hypothesis is unclear. There is also concern that the depressive realism effect is merely a byproduct of the depressed person being in a situation that agrees with their negative bias.