Lab 3: Generalized Motor Programs

In Chapters 5 and 6 of your text, Schmidt and Wrisberg discuss the motor control concept of open-loop control and motor programs. As the text describes, the difference between the idea of a motor program (MP) and a generalized motor program (GMP) is that a GMP describes a pattern of movement or class of movements. So we walk at one kilometre per hour using the same pattern of movements as we do to walk at three kilometres per hour. In the older concept of a motor program the two speeds would have been assumed to be controlled by different programs. GMP theory suggests that surface features (called parameters) of a movement are changeable (e.g., walking speed), whereas the deep structure (which is often the relative timing of the action) is constant for actions controlled by the same GMP. This lab will explore these ideas with the hypothesis that handwriting is controlled by a generalized motor program.

Methodology

Participant

Two right-handed participants with fairly legible handwriting (both male or both female) will be tested. It will be necessary to procure a naïve observer who will make judgements about “movement style” (see dependent variable below). The observer should know nothing about the test conditions nor the research hypotheses.

Material/Equipment

All that is necessary are pieces of lined (note taking) paper and a medium ballpoint pen. For normally lined paper the lines are typically about 8 mm apart.

Procedure

On a single trial the participant will write the phrase, “John Smith loves pears”, using his/her normal writing style while attempting to be “neat”. Allow the participant 2-3 practice trials under each condition.

The phrase will be written under five different conditions:

  • phrase written (normal height) with the right (preferred) hand, with the writing spaced between two adjacent lines (i.e., a “t” would be approximately 8 mm in height and an “a” would be about 4 mm in height),
  • phrase written (double height) with right hand with the height of the letters doubled (i.e., an “a” would fill the space between adjacent lines and be 8 mm and a “t” would fill two spaces and be 16 mm in height)
  • phrase written (triple height) with the right hand (i.e., a “t” would be 24 mm in height and fill three spaces)
  • phrase written (normal height) with the left hand between adjacent lines,
  • phrase written (normal height) with the right hand, with the eyes closed.

The second participant is to perform under the same conditions as above.

Dependent Variable

Without sophisticated measurement equipment it is difficult to make a decision about whether actions are controlled by the same GMP. For example, Figures 5.7, 5.8, 6.1, and 6.3 have used different laboratory measurement techniques (Note: you will learn about these techniques in upper years of the Kinesiology program).

The first step in our process will be to convert all writing to the same height using a photocopy machine or a scanner. The preferred technique is to reduce the size of the larger writing conditions by 50% (double height) and 33% (triple height).

Without sophisticated equipment we cannot identify “deep structure” as indicated by relative timing or relative force, but people often have a “sense of this” simply by observing movement. For example, we have no difficulty “seeing” the difference between running and walking or the similarities between two walking speeds. We will refer to this as the “movement style”.

Using a naïve observer to make judgements about movement style, he/she will be asked to make the following visual comparisons:

  1. compare the three right handed conditions (different heights shrunk to similar sizes) for each of the two participants,
  2. compare the right and left hand conditions (normal height) for each of the two participants,
  3. compare the right hand condition (normal height) of participant one versus participant two,
  4. compare the eyes open and eyes closed right hand conditions (normal height) for each of the two participants.

For each comparison the observer is asked to say whether he/she feels the writing is “generally similar” or “generally dissimilar”. In either case, ask the observer to briefly explain their judgement (you may wish to refer to their comments in your discussion). It is assumed that a judgement of “generally similar” means the movement style was governed by the same GMP and “generally dissimilar” a different GMP.

Results

Prepare a figure or figures with all writing (electronically) made the same height (see Figure 5.9 in the text). Make sure the different conditions are clearly labelled. Either have one figure displaying all conditions for both participants or a separate figure for each type of comparison made by the observer (see #1 to #4 above).

Also prepare a table that summarizes all of the judgements made by the observer. For example, the table could have two columns labelled “similar” and “dissimilar” with separate rows for the different comparisons made.

Discussion

  1. Is handwriting controlled by a generalized motor program? Explain (you will want to refer to pages 139 to 143).
  2. Using the concept of open-loop control, explain whether it was possible for the performer to produce the desired output with eyes closed.

Form for write-up

  1. Maximum word count for report is 300 words.
  2. On top right (as a header) put your name, student number, and word count.
  3. Your report will have the following parts:
  • title (centred at top of page)
  • 1-2 sentences as introduction including your research hypothesis (what you think will happen.
  • results section (titled and centred “Results”) – clearly labelled table and figure(s).
  • discussion section (titled and centred “Discussion”) – number your answers to the questions (see above).

Marks

  1. Overall presentation of paper 20%
  2. Results (presentation quality & clarity of picture)30%
  3. Question one 30%
  4. Question two 20%