Using Sex Differences to Link Spatial Cognition and Program Comprehension

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Using Sex Differences to Link Spatial Cognition
and Program Comprehension

• Maryanne Fisher, Anthony Cox, Lin Zhao
• Presenter Manas Hardas
• Program Comprehension, Spring 2008

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Authors
Lin Zhao Dalhousie University Graduated in 2007
Maryanne Fisher Department of Psychology Saint
Mary's University Research Interests
Intrasexual Competition, Gender and Program
Comprehension
Anthony Cox Faculty of Computer Science
Dalhousie University Research InterestsHuman
Factors in Computing, Program Comprehension, and
Tool Use/Evaluation
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Whats it about?

• Spatial cognition and program comprehension are
  cognitively similar tasks
• Navigation through real maps (sort of spatial
  cognition) is similar to navigation through code
  (sort of program comprehension!)
• Navigation through real maps is done using survey
  maps or route maps approach. Whereas navigation
  through code is done using top down or bottom up
  approach.

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Continued

• Route maps based approach bottom up approach
  cognitively low risk approach typical to
  women
• Survey maps based approach top down approach
  cognitively high risk approach typical to men
• Assuming of course that a high risk taker will
  always take high risks and low risk taker will
  always take less risks

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Introduction

• New cognitive skills are developed on previously
  acquired skills. Each new task doesnt need whole
  new set of skills ! (Chown et.al. 95, Clark 89)
  
• Program comprehension being relatively new, the
  cognitive skills required for it must be
  developed from existing ones ! i.e. spatial
  cognition.
• Navigation skills in real-space is similar to
  those in virtual space (Vinson, 99).

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Codespace

• Mental map of source code codespace
• Mental maps or codespace uses spatial imagery
  (Green 95,97, Douce et.al. 99)
• Thus mental map concepts are in context of
  space !
• Programmers must form mental maps because they
  dont navigate sequentially and can jump between
  code artifacts (Mosemann and Wiedenback 01).
• Thus,
• navigation of source code ? program comprehension
• navigation of source code ? navigation in real
  time
• navigation in real time ? spatial cognition
• Therefore, program comprehension ? spatial
  cognition !!!

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Program Comprehension
Program Comprehension

• source code
  mental models
• Topdown Form hypothesis and go on validating
  or dismissing them going from high level to low
  level of abstraction (Brooks 83, Soloway et.al.
  84)
• Bottom-up Construct control flow program model
  to concept based situation model going from low
  level to high level of abstraction (Pennington
  87)
• Opportunist Based on experience use as needed
  (von Mayrhauser 94)
• However all strategies need software navigation.

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Spatial cognition

• A process composed of a series of psychological
  transformations by which an individual acquires,
  stores, recalls, and decodes information about
  the relative locations and attributes of the
  phenomena in their everyday spatial environment.
  (Downs and Stea 73)
• Simply put, cognitive skills that enable you to,
• learn
• memorize
• remember
• and interpret
• objects, their location and other attributes
  (length, width, physical proximity etc.) in a 3-D
  space.
• Just like driving (navigating) your car !

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Spatial cognition elements

• Way finding Ability to find your way using
• Landmarks
• Route maps sequence of instruction involving
  landmarks
• Survey maps topological maps describing spatial
  layout
• 75 of population use route maps (Appleyard 69)
• Person uses strategies on individual preference
  (Aginsky 97)
• Person uses multiple strategies (Kitchin 97)
• People with better sense of direction used
  multiple strategies and switched more
  appropriately (Kato and Takeuchi 2003).

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Elements of spatial cognition continued

• Object location memory Ability to recall
  position of objects
• Different levels of abstraction (recalling where
  your toe is, is way different than recalling
  where the student center is!)
• Ability measure using test developed by Silverman
  and Eals (1992), modified by James and Kimura
  (1997) to also include location shift or location
  exchange.

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Elements continued

• Mental rotation Ability to manipulate a 3-D
  object such that we can visualize the object from
  different perspective.
• Measure using Vandenburg and Kuse (1978) mental
  rotation test. Given a 2-D image, identify its
  3-D image from different solutions.
• Thus spatial cognition is a complex task
  consisting of way finding, object location and
  mental rotation like tasks which are often
  performed opportunistically as is program
  comprehension.

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Difference between men and women!

• Risk taking It is well established that men
  take more risks than women (Daly and Wilson
  2001)
• More code more mistakes. Therefore, women must
  tend to write shorter pieces of code and compile
  more often ? women must be using more bottom-up
  lower risk approach to assist their style of
  debugging!
• Persons risk taking behavior remains constant.
  (reference needed)
• Thus, women bottom-up approach low level of
  abstraction similar to landmark (object)
  identification use route-based navigation
• Huge leap in assumptions !!!
• women can just be better designers!
• risk taking in social life may not necessarily
  imply risk taking in software development! (maybe
  rash driving has a correlation)

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differences continued

• Men top-down approach high level abstraction
  similar to mental rotation used by survey
  based navigation !
• Assumption here is that, every person uses same
  skills to perform a particular task. Can I use my
  cognitive skills I developed to eat, for reading
  tasks. Or rather, can I use someone elses
  cognitive skills he/she developed to eat, to
  read?

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Comparing spatial cognition and program
comprehension

• Although it seems that there are similarities in
  both there are actually significant details when
  examined carefully.
• These differences are only brought out when
  discussed in context of sex differences i.e.
  risks involved in both
• Both have low risk tasks (route-based navigation
  and bottom-up program comprehension) and high
  risk tasks (survey-based navigation and top-down
  program comprehension) which are only brought to
  light when discussed in terms of men and women.

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Experimental validation

• Setup
• Test the use of spatial cognition (object
  location and mental rotation) as they are used in
  the codespace
• Participants asked to perform maintenance on 300
  line Java calculator program consisting of 1
  class and 10 functions (small code for high
  quality of experiments)
• Post maintenance questionnaire to test
• 30 participants (7 undergrad and 23 grad, 3 from
  Engineering, 2 from science and 25 from computer
  science)
• Half male with average age 27, half female avg.
  age 25

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Procedure

• Three tasks
• Switch positions of two buttons
• Change type of variable from primitive type
  double to class Double
• Change background color to blue and button to
  magenta

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Post maintenance tasks

• After maintenance, participants sort methods as
  they appeared in the code (test for recall,
  object location)
• Participants locate method in particular lines of
  code (0-75, 76-150 etc.) (test for location)
• Participants were then given pairs of methods and
  guess which occurred first (test for location
  with respect to another method)
• Participants guess length of methods (test for
  object recall)
• Participants were then given pairs of methods and
  guess LOC between the two methods (test for
  location w.r.t. each other)
• Participants take Vandenburg and Kuse mental
  rotation test.

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Findings

• Location and Object memory
• No significant difference between men and women!
  (a 0.05)
• Location memory significantly correlates with
  post maintenance task 1, 3 and method sort, but
  men perform bad in location memory task.
  Therefore correlation is a sequence of womens
  abilities.
• Womens location memory highly correlated to
  cards sort as against mens.
• Object memory not correlated for post maintenance
  tasks for either, however significantly
  correlated to womens maintenance tasks.

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Findings

• Mental Rotation
• No significant difference for either.
• Womens mental rotation did not significantly
  correlate but mens does for maintenance tasks.

Inference

• Women have high correlation for object memory
  and location memory which is a more route map
  based bottom up approach while men have
  significant correlation with mental rotation
  which is essentially a survey map based top down
  approach.

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Future Work

• Landmarks Beacons (sort of)
• Use for navigation by feature location
• Composition of landmarks by beacons
• Roles in program comprehension and spatial
  cognition
• Visual Subsystem
• Human visual system of contour identifies object
  and human visual location system determines
  spatial location (spatial cognition)
• How humans look for concepts in source code
• Risk taking during comprehension
• Risk taking behavior determines which approach
  for comprehension

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Conclusion

• Program comprehension is correlated to spatial
  cognition in terms of navigation
• Difference between men and women in risk taking
  highlight similarities between PC and SC.
• Complex model and experiment, not completely
  conclusive.
• Results can help in creating tailored tools for
  program comprehension (instead of tailored
  people!)
• Will help educators
• Depending on sex based differences, instruction
  can be tailored based on the population

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Thoughts

• Good paper!
• Well written and straight forward, has its short
  comings an makes some big assumptions but not
  hesitant to mention them.
• Conspicuously lacking in figures and tables
  because of unnecessarily complex non symmetrical
  experimentation or presentation of results.
• The idea of relating cognitive skills required to
  comprehend programs may be similar to cognitive
  skills required in spatial cognition is
  interesting. Should look at other tasks which
  could need similar skills, script/story/poetry
  writing?!!!

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Thank you! Questions?