fixedness problems
Functional fixedness problems require an unfamiliar item/object to be used in a novel way to reach the solution (e.g., Duncker, 1945; Maier, 1931,1945). As past experiences can inhibit general problem solving (James, 1890; Reason, 1990), it is not surprising that in solving functional fixedness problems, our experiences and
functional attributes (Keane, 1989), and an unwarranted impasse may result that can only be overcome through representational change (Ohlsson, 1992). This is consistent with what Reason (1990) proposed. That is, in cognitively underspecified situations solvers tend to default to high frequency responses. To overcome functional fixity, a specific form of representational change is required in that the solution generated must include a novel, unusual function for an object mentioned in the problem specification (Dunker, 1945; Maier, 1931). Therefore, similar difficulties are encountered in solving both verbal insight problems, studied in Chapter 4, and functional fixedness problems, as it is the unhelpful reliance on past habits which impedes performance on both types of problems. The remainder of this section provides a brief discussion of the evidence in support of functional fixity to demonstrate the importance of divergent thinking in overcoming functional fixity.
A number of experiments have attested to the existence o f functional fixedness (Adamson, 1952; Birch & Rabinowitz, 1951; Duncker, 1945; Frank & Ramscar, 2003; Maier, 1931). For example, Maier (1931) found that participants were unable to generate a novel function for pliers in the two-string problem until the experimenter provided a hint. Duncker’s (1945) candle problem is perhaps more famously known for demonstrating functional fixedness. Participants were set the task of attaching a candle to a wall so that it can bum upright, with only some matches and a box of drawing pins. Duncker found that participants tried to attach the candle directly to the wall with the drawing pins, or to glue it to the wall by melting it. It was concluded that participants were ‘fixated’ on the box’s normal function o f holding the drawing pins and could not reconceptualise it as a platform to solve the problem.
Adamson (1952) replicated experiments using functional fixedness problems conducted by Dunker (1945) due to limited original data. Participants in the
experimental ‘pre-utilisation’ condition experienced initial functions for objects in the problems which were intended to inhibit problem solutions (i.e. boxes in the candle problem were presented with items in them so their function as a container was prevalent). Control participants were given the problems without any pre-utilization so no prior functions for items were displayed (i.e. boxes were presented empty to participants). The solution rate for the experimental condition was more than twice than that of the control condition. These findings provided further support for functional fixity and suggested that those who utilise an object for a particular function in the past will have greater difficulty solving problems that require a novel function for that object. That is, past experiences reinforce the typical function of an object which has a pervasive effect on problem solving.
Both Adamson (1952) and Duncker (1945) used the same situation for the pre utilisation and new task, therefore it was difficult to determine what aspect of the tasks was most difficult for participants. Furthermore, there was no control for the experience participants had with objects prior to the experiment (Mayer, 1992). To overcome these criticisms, Birch and Rabinowitz (1951) adapted Maier’s (1931) two- string problem. They presented two experimental conditions with different pre-tasks while a control condition received no pre-task. Findings demonstrated that the situational context influenced what function is generated for a given object. In particular, participants’ previous experience (gained during the pre-task) led them to use objects in a certain way and functional fixedness did not allow them to perceive the objects to be used for another purpose. Thus, the context of a problem can also have a strong inhibitory effect in solving functional fixedness problems, as a habitual response results in the formation of an incorrect representation which consequently prevents the solver from generating a novel or unusual function for an object.
More recently, Frank and Ramscar (2003) found that performance on Duncker’s (1945) candle problem was dependent on participants’ lexical
representation o f the concept ‘box’ rather than the instructional manipulation i.e., when noun phrases such as ‘box of matches’ were underlined, or only when nouns such as ‘box’ were underlined, or when the same instructions used in the original experiment were employed. They suggested that overcoming functional fixity in the candle problem is dependent on having a flexible representation o f the word ‘box’ in order to realise that the box can serve as a platform to attach the candle to the wall.
The above studies illustrate that functional fixity can prevent divergent,
flexible thinking i.e., thinking that entails generating numerous solutions to a problem (e.g., different uses for a brick), which may be an underlying process in insight
problem solving (DeYoung et al., 2008; Gilhooly, Fioratou, Anthony, & Wynn, 2007; Gilhooly & Murphy, 2005). DeYoung et al. (2008) suggested that breaking frame (similar to breaking out of functional fixedness; Dunker, 1945) and divergent thinking were two broad cognitive abilities that both independently predicted insight. That is, breaking frame is necessary to avoid persevering with an incorrect problem
representation, while divergent thinking is necessary to generate elements of a new representation. Further, flexibility also independently predicted insight, thus
suggesting that the ability to switch between perspectives may be an important aspect of divergent thinking.
Chrysikou (2006) utilised training in functional fixedness problems but tested performance across a range of different test problems which included verbal insight, visuo-spatial and functional fixedness problems. Training entailed participants
completing an Alternative Categories Task (ACT), which is a variation o f the Unusual Uses Test (Christensen & Gilford, 1958). The task was presented in the form of a
questionnaire and required participants to generate up to six common categories for 12 items including a shoe and a fork. For example, it was stated that for ‘shoe’, the common category was ‘item used as a footwear’. The Alternative Categories with Critical Items Task (ACT-C) was similar to ACT but participants in this condition were also given items that were critical to solving the test problems e.g., ‘box’ which is of importance to solving Duncker’s (1945) Candle problem. Although the training appeared to be specific to solving functional fixedness problems, a training effect (57%) was found across all test problems even when the critical item was not included in the task. It appears that the training encouraged divergent thinking, which is
particularly important in solving functional fixedness problems, although in this case it encouraged participants to assess alternative interpretations in triggering
representational change, as suggested by the positive training effect.
The above studies support the Gestalt ( Kohler, 1924; Wertheimer, 1945) and representational change (Knoblich et al., 1992, 2001; Ohlsson, 1992) perspectives of insight problem solving as past experiences trigger stereotypical responses, which in this case is a typical function of an object, that impede problem solving. Perhaps more importantly, the results draw attention to the role of restructuring or representational change in overcoming functional fixity. In other words, a switch in representation is needed to access low probability hypotheses that tend to be overridden by default, high probability hypotheses that in most situations are correct (Patrick et al., 1999). For example, in Maier’s (1931) two-string problem, participants were unable to restructure their initial interpretation of the function of the pliers to serve as a pendulum weight without experimenter intervention (Adamson & Taylor, 1954). Similarly, solvers were unable to consider the box in the candle problem to serve as a platform to hold the candle (Dunker, 1945). It could be argued that that these
problems were made more difficult because real objects were provided within the problem context. Consequently, this may have strengthened the habitual response concerning the typical function of a particular object, therefore making it harder for the solver to overcome functional fixity. On the whole, research indicates that training to overcome functional fixity needs to be devised that encourages divergent thinking such that participants generate several uses for familiar objects in the hope o f
facilitating restructuring. Hence, the common function for an object, that is usually unhelpful, is abandoned early on during problem solving.