A CostBenefit Model of Choice: Walking and Saving Steps

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A Cost-Benefit Model of
ChoiceWalking and Saving Steps

• Stephen Bitgood
• Stephany Dukes
• Jim Shurbutt
• JACKSONVILLE STATE UNIVERSITY
• Presented at the 2005 Association for Behavior
  Analysis Annual Meeting in Chicago, IL

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Summary

• The walking patterns of people illustrate how
  costs (time and effort) as well as benefits
  (positive reinforcers) play a critical role in
  choice behavior. People tend to decrease the
  cost of walking by exerting the least amount of
  effort as reflected in movement patterns. In
  this presentation, studies from three
  environments are used to illustrate this economy
  of walking principle.

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Choice Behavior

• Choice behavior is strongly influenced by the
  cost/benefit ratio
• Both the benefits (positive reinforcers) and the
  costs (time and effort) influence the behavior
• Walking behavior is only one of many examples of
  cost-benefit choice behavior

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Other Models of Choice

• The discounting function and matching law are
  two, well-researched examples of choice behaviors
  that illustrate organisms maximize reinforcement
  and minimize costs
• We believe these models are special cases of the
  cost-benefit choice analysis.

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The Cost-Benefit Ratio

• Consider the simple relationship
• Choice f(benefits/costs)
• Where benefits positive reinforcers
• and costs time and effort
• This relationship has at least one very important
  implication!

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Implication

• Time and effort (costs) have a greater impact on
  choice behavior than the value of positive
  reinforcers (benefits).
• This mathematical relationship can be seen if
  costs are decreased while benefits are held
  constant compared with benefits increasing while
  costs are held constant
• This assumes an adequate level of reinforcer
  available

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Figure 1. Comparison of increasing benefits
versus decreasing costs
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Walking behavior

• Reinforcers reaching a destination exercise
  tension reduction, etc.
• Costs walking time amount of effort risks from
  traffic, etc.

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Examples of Reducing Costs

• New Urbanists communities are designed for
  walkability (5-10-min walk to the town center)
• Shoppers at big box retail stores typically try
  to find the parking space closest to the entrance

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Walking in Three Settings

• Shopping malls a study of pedestrian movement at
  intersections reveals patterns that save steps
• Museums several patterns of pedestrian movement
  are best explained by reducing time and effort
  (cutting the costs)
• University campus if driving between classes has
  lower costs than walking, students will choose to
  drive

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Reducing Costs by Saving Steps

• Our empirical observations in these three
  settings lead to the conclusion that people
  reduce the costs of walking by saving steps.
• The following figure of an intersection in a
  public setting illustrates how people can save
  steps

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Explanation of Figure 2

• The figure combines choice behavior (turning
  right or left, moving straight ahead) with side
  of walkway (right or left) to obtain six
  patterns.
• Four patterns represent least effort and two
  cross-over patterns (left side-right turn, right
  side-left turn) require more steps.
• If least effort is the most important variable,
  then few visitors will be observed in cross-over
  patterns.

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Walking in Shopping Malls

• The choice patterns at mall intersections were
  divided into Least steps and Most steps
  consistent with Figure 2.
• We observed four samples of pedestrians
  (N100-105) in two malls at three intersections
• Replicated across malls (2), intersections (3),
  and direction of traffic flow (sample 3 and 45
  at the same intersection from different
  directions)
• Included reliability check (samples 4 5)
• Protocol select first group to cross an
  imaginary line follow until past intersection
  record side of corridor and direction through
  intersection.

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Sample 1
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Sample 2
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Sample 3
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Samples 45
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Discussion

• Observed patterns
• Least effort choice patterns (very few
  crossovers)
• Majority of pedestrians were right-side walkers
  (but percentage varied depending on direction
  (presumably influenced by destination)
• Possible alternative explanations
• Cant argue destination influenced choice at
  intersection because there would be more
  crossover turning (right-left and left-right)
  also note replications (direction, intersections,
  etc.)
• Cant argue that oncoming crowds made it
  difficult to cross over because it was rarely
  very crowded (although crossover effort would be
  another example of least effort)

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Walking in Museums

• To avoid the onset of museum fatigue, visitors
  usually adapt walking patterns that conserve
  energy
• Although having visitors approach museum objects
  to view is the major goal of exhibit designers,
  this tendency is in conflict with the principle
  of least effort. An object must be highly
  reinforcing to break the least effort pattern

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Visitor movement involving least effort

• Patterns from the literature include
• Turning right (if visitors are walking on the
  right side since it involves fewer steps than
  turning left)
• Inertia (walking in a straight line unless an
  object attracts considerable attention)
• One-sided exhibit viewing
• Reluctance to backtrack to view all exhibits
• Exiting a gallery at the first open door

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Other evidence for least effort

• Number of words per exhibit label is critical
• As the number of words approaches 100, there is a
  considerable drop off of reading
• Visitors are less likely to view objects that
  requires walking extra steps from the main pathway

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Review of Museum Literature

• See Bitgood, S., Dukes, S. (in press). Not
  another step! Environment and Behavior

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Walking on Campus

• At JSU students have the option of driving or
  walking to class
• Since the cost of walking (time and effort) is
  greater than the cost of driving, the vast
  majority of students drive from one class to
  another
• To change the costs and benefits of walking and
  driving, two major changes are needed
• Reduce the cost of walking (classes closer
  together
• Increase the cost of driving (restrict driving,
  assign parking lots, etc.)

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JSU Campus park-walk project

• For a description of this project, please request
  paper from the authors.

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Contact information

• Stephen Bitgood, Ph.D.
• Professor of Psychology
• Jacksonville State University
• Jacksonville, AL 36265
• E-mail scbitgood_at_aol.com
• Ph. 256-782-5640