1. Problem Solving and Decision Making

What is problem solving?

1. two states: current position and goals

2. route between two are not clear

3. route takes multiple steps

What are three characteristics of problem solving?

• is purposeful - goal-directed

• controlled processes - not fully automatic

• lack appropriate knowledge to generate immediate solution

Example of problem solving: making a cup of tea

• doesn’t need to be a controlled process if you know where things are and what to do

What did Goel & Grafman find studying an architect with a frontal lesion?

• asked them to design a lab/office space

• struggled to progress from problem structuring to problem solving

• poor final design due to problem solving difficulties

What is involved in a well-defined problem?

current position, possible moves and goal well specified e.g., Chess

What is involved in an ill-defined problem?

current position, possible moves and goal not well specified e.g. most problems in life

What is involved in a knowledge-rich problem?

only solvable via relevant knowledge e.g. chess

What is involved in a knowledge-lean problem?

• can be solved without needing prior knowledge

• all information contained in presentation of problem

• e.g. most lab-based examples

What is involved in the Monty Hall Problem?

1. Pick a door

2. One of the other 2 doors opened, revealing a goat

3. Two doors left, do you keep with the door you selected in (1) or switch to the remaining door?

What is the point of insight in problem solving?

• point at which the solution to problem is suddenly seen

What is the two string problem? SS

What did Metcalfe and Wieve (1987) find regarding insight?

• participants rated “warmth” during problem solving task - proximity to goal/solution

• for problems that often included “insight”, sudden increase in “warmth” i.e. rapid, sudden progress

• for problem that often solved without insight, gradual increase in “warmth” - i.e., slow accumulation to goal

What did Jung-Beeman et al (2004) find regarding insight?

• remote associates test

• fence, card, master - post

• indicate “insight” for particular trials

• increased activity in superior temporal gyrus

What did Ellis et al (2011) find regarding the conscious and unconscious aspects of the experience of insight?

• Anagram task: KAFMS

• record eye-movement during task

• participants report sudden solution

• however, gradual decrease in fixations on non-relevant letter

• gradual accumulation of knowledge despite subjective experience of ‘ah ha’

• might it be unconscious

How can the debate regarding insight be summarised?

• insight is ‘real’ in the sense that people experience it

• however, it may not be a separate cognitive process - higher order processes may gradually arrive at solution but we only become aware once threshold reached

• However, does ‘gradual accumulation’ concept make sense for all complex problem solving tasks

How can insight be facilitated? simple first one

hints - e.g. two string problem

How can insight be facilitated?

• incubation

• stop directly thinking about the problem for a period of time

• most have experienced the feeling of solving a problem during this

• Sio & Ormerod (2009) - meta-analysis

• incubation led to small but consistent improvements in problem solving, particularly for problems that required more ‘creative’ solutions

How can insight be facilitated?

• sleep

• wagner et al (2004)

• often told to ‘sleep on it’

• wagner found that sleep increased insight - number strings where a “hidden rule” is present

What did Newell and Simon suggest regarding problem solving strategies?

• problem solving from an information processing perspective (e.g., like a computer)

• limited short-term memory capacity

• complex information processing serial

• can’t hold all steps in mind at once

• trade-off: accuracy vs computational complexity (and vs time)

• rely heavily on ‘heuristics’ - computationally cheap rules of thumb that can produce reasonably accurate answers

What is involved in means-end analysis with heuristics?

• form sub-goal to minimise distance between current location and goal, move towards sub-goal

• however, (1) requires info about location of final goal and (2) what is better strategy to move away from final goal (e.g., in maze)

What is involved in hill climbing in heuristics?

• change present state to one closer to end goal

• simpler than means-end, as no explicit ‘sub-goal’

• analogous to climbing hill by always moving to next highest point - can get caught in local maxima

What is involved in planning as another strategy for problem solving?

• planning before trying to reach goal

• useful when reaching goal involves sequence of behaviour - e.g. making a cup of tea

What did Koppenol-Gonzalez et al (2010) find regarding planning as another strategy for problem solving?

• tower of london task

• participants who spent longer deliberately planning moves before acting performed better, with fewer errors than those who didn’t plan

What is involved in progress monitoring as another strategy in problem solving?

• track progress towards goal and switch strategy if progress is slow

• MacGregor et al (2001): performance worse when ppts thought progress being made

• when ppts realised progress was slow, they were more likely to switch strategies

• However, how is ‘progress’ measured or defined

• what defines whether ‘progress’ is fast/slow?

How is expertise defined?

high level of knowledge and performance in a given domain acquired through a long period of systematic study/practice

How is expertise related to problem solving?

• lab tasks are often knowledge-lean. Abstracted away from real world knowledge e.g. tower of london

• expertise important for solving many real-world problems - problems in real world often knowledge-rich

What did DeGroot find regarding expertise in problem solving?

• chess

• experts remember positions on chess board, but not better memory in general

What are the different kinds of processes relevant to expertise in problem solving?

chess

fast processes

• charness et al (2001): eye movements in first few seconds to more ‘relevant’ pieces in experts

• burns: high correlation between normal and ‘blitz’ chess

slow processes

• as time to make move decreases, skill differences less predictive of outcome

• longer time to make moves leads to better performance

How does medical expertise relate to problem solving?

• medical decisions really matter - sometimes life or death - unlike chess

• serious problem - false negative <=30% in diagnosis of certain diseases via X-ray

• Krupinksi et al: breast biopsies by pathologists in training, reduction in number of fixations/image, fewer fixations on non-diagnostic regions

• Kundel et al: mammograms of possible breast cancer, mean search time around 27 secs, but time to fixate on cancer - around 1.13 (less than 1 for experts). correlation between speed of fixation on cancer and overall detection performance

What is functional fixedness in experience gone bad?

• the inflexible focus on the usual function of an object

• can’t see novel use of object to solve problem

What is “mental set” regarding experience gone bad in problem solving?

• we tend to use a familiar strategy that was successful in the past, even when it is not appropriate

• Bilalic et al (2008): chess experts don’t always find the quickest route to victory. Often find longer solution based on familiar strategy

What is involved in the representational change theory?

• Ohlsson argued that we often encounter a block or impasse when solving a problem because we have represented it wrongly - we typically need to change the problem representation for insight to occur

1. constraint relaxation: inhibitions on what is regarded as permissible are removed

2. re-encoding: some aspect of the problem representation is reinterpreted

3. elaboration: new problem information is added to the representation