Principal Investigator:
James Fozard
Collaborating Investigators: Alan Welford, Arthur Norris, Nathan Shock.
Year First Collected: 1959
Year Last Collected: 1962
Frequency of Collection: Every visit, but varied depending on time and personnel constraints.
Subset Data Files on the VMS Cluster? Files info159.*, Inactive as of 11/97.
Available to all users authorized to access Common BLSA Data Set.
Data Type Notes:
(none)
Descriptive History:
Information Type 159 (4 cards)
Clarification of data element desciption:
Type 159 was used in 1961 and 1962. Type 151 was used from 1962 until 1981. Type 151
differs from Type 159 in two significant ways. On card one, col 68 of Type 151, right or
left-handed indicated. Type 151 but not Type 159 has cards five and six, both of which contain
qualitative interpretations of the performance of the participant. Card six was apparently very
seldom used. There are only eight records in the computer file. It is unlikely that the differences
between the cards will be of any impotence in analyses of the data.
The participant's main task was to alternate pencil taps between two targets. The time taken to
make 100 alternate taps was the time measure referred to in the documentation. In a control task,
the participant made repeated taps in the same target--no moving between two targets. The time
refers to the time required to complete 100 taps in the same target.
There were nine conditions in which the participant alternated between targets. The targets
themselves differed in width: small(S)=4mm; medium (M)=11mm and large (L)=32mm. The
separations between the two targets were narrow (N)=50mm, intermediate(I)=142mm, and wide
(W)=402mm. Thus SW on Card 01, cols 01-02 refers to small width, wide separation or
amplitude of movement.
For each separation, there were four measurements. Use Card 01, cols 01-10, SW, as the
example.
Cols 01-02 SW W1: width of shots (W') on the left-hand target
Cols 03-04 SW W2: width of shots (W') on the right-hand target
Cols 05-06 SW D1: distance between leftmost shot on a left-hand target and rightmost shot on a
right-hand target (A').
Cols 07-08 SW Time required for 100 alternate taps
This sequence is repeated for Targets SI, SN, MW, MI, MN.
Cols 61-62 width of shots for single target
Cols 63-65 time for 100 shots on single target
Cols 68-68 left or right handed
Card two
Cols 01-30 continues as in card one for LW, LI, LN.
Cols 31-40 tapping in a single target--as in card 1, 5-10cm and 10-15 cm refers to the
approximate height that the participant was to hold the pencil from the paper during the 100 taps.
Cols 41-49 three calculated values: Written documentation for the formulas is maintained in LSS
and explanation is in Brogmus (1991), copy of which is in LSS.
Cards 3-4
On first visits, the procedure was given twice, the second set was used. For repeat visits, data
from card one and two only are used--the test was not repeated a second time.
Descriptive history:
The goal was partly descriptive and partly designed to evaluate Alan Welford's reformualtion of
Fitts' law. Fitts' law related the time it takes to make a hand/arm movement to the width of the
target and the distance or amplitude between two targets. The law is defined with respect to
reciprocal movements between two targets. The basic formula is MT= a+blog2(2A/W) where
MT is movement time, A being the amplitude of the movement, W being the target width and a
and b being empirically derived constants.
The data were collected between 1962 and 1981. One report by Welford, Norris and Shock was
published in 1969. Data were collected without further analysis until the testing was stopped. A
second analysis of the cross-sectional and longitudinal data is described in the unpublished
master's thesis of George Brogmus (1991). The status as of July 1997 is that one report is under
review by a journal, and a second is in preparation. In the final years of his life, Welford was
able to contribute to the interpretation of the analyses. This resulted in a reanalysis of some of
Brogmus' work.
In ergonomics, Fitts' law is widely used. The value of the BLSA data is the refinement of Fitts'
law to take into account age and gender differences. The theoretical significance is it's
description of gender differences in strategy on the task across the adult lifespan and its
usefulness in relating changes in the relationship between movement speed and accuracy (or
consistency) of reciprocal movements.
Data collecting instruments:
Standard paper targets were used to collect data so that it was possible to measure the width of
the scatter of points in the targets. The only records are electronic. After removal of participant
identification, the original paper records were given to Dr. Max Vercruyssen who was in charge
of the team that analyzed the data.
The procedure for calculating the constants named in the data cards is contained in
documentation maintained in LSB. The discussion of the procedure and the analyses of the
results is contained in the master's thesis by Brogmus (1991) at the University of Southern
California; a copy is maintained in LSS.
Investigators:
JL Fozard 1985
Alan Welford was the person responsible for designing the study and supervising the initial
analyses. Coinvestigators were Arthur Norris and Nathan Shock. All are deceased. Initiation of
the more recent analyses was by JL Fozard, Ph.D. in LSB in 1989. The more recent analyses
were carried out by George Brogmus as part of his master's thesis research at the University of
Southern Califormnia, under the direction of Prof. Max Vercruyssen, whose address in 1997 is
1386 Frank Street, Honolulu, HI 98916, Tel. 808 734-8916. Support for the work was provided
by a professional services contract with the University of Southern California.
Related protocols: None.
Frequency of collection: Every visit, but varied depending on time and personnel
constraints.
Inclusion/Exclusion rules: All consenting participants.
Publications:
Brogmus GE. Effects of age and gender on speed and accuracy of hand movements: and the
refinements they suggest for Fitts' law. Unpublished Masters' thesis, University of Southern
California, 1991.
Welford AT, Norris AH, Shock NW. Speed and accuracy and their changes with age. Acta
Psychologica 1969;30:3-15.
Vercruyssen M, Brogmus GE, Welford AT, Fozard JL. Ongitudinal changes in speed and
accuracty of hand movements. J. Gerontol: Psychol Sci, submitted.