Franklin M. Henry

Increased Response Latency for Complicated Movements and A “Memory Drum” Theory of Neuromotor Reaction

Abstract The theory proposes a nonconscious mechanism that uses stored information (motor memory) to channel existing nervous impulses from brain waves and general afferent stimuli into the appropriate neuromotor coordination centers, subcenters, and efferent nerves, thus causing the desired movement. A consequent hypothesis requires that the simple reaction time will become longer when the response movement is required to be of greater complexity. Data obtained on college men and women, and 12- and 8-year-old boys, are in agreement with the hypothesis. Replacing a very simple finger movement with an arm movement of moderate complexity slows the reaction by about 20 percent; additional complexity produces a further slowing of 7 percent. The speed of the arm movement is considerably faster in college men than in younger boys or in college women. The correlation between reaction time and speed of movement averages approximately zero. Individual differences in ability to make a fast arm movement are about 70...

Use of simple reaction time in motor programming studies: a reply to Klapp, Wyatt and Lingo.

Following a more explicit explanation of the 1960 memory-drum theory and the reasons for using the simple (rather than choice) RT method in testing predictions based on it, the eight experiments utilizing large-scale precued arm movements constrained as to directional accuracy are reviewed. In all cases, increasing complexity of the movement consistently increased response latency; control RT levels agreed with well-established typical values for auditory and visual stimuli. Following practice the complexity effect leveled off, retaining a significant latency differential. Results from experiments varying duration of a held movement position (with movement minimal and complexity invariant) are not relevant to these studies.

Variable and constant performance errors within a group of individuals.

The correct individual single score for a within-S series of errors e about the target (for k trials) is E= √∑e(2) /k= √V(2) +C(2); the commonly used absolute error AE under-represents or deletes the variable error component V. In correlational analysis, the constant error score should be C absolute and V should be used unsquared in order to avoid curvilinearity; in general, r patterns across Ss are not predictable from within-Ss relations. While V and C are necessarily independent within Ss, they usually exhibit substantial correlation across Ss; evaluation of the role of each is sometimes important. Linearity of regression is demanded; it, rather than non-skewness, is shown to be the important assumption in using r. If relations involving algebraic C are of interest, the correlation index may be required because of U-shaped regression. Several common statistical misinterpretations are discussed.

Absolute Error vs "E" in Target Accuracy.

The composite error E (i.e.,√ (v(2) + c(2)) yields a multiple R approximating unity with the variable error v and constant error c, however, v is not adequately represented in all of the absolute error scores Ae as verified by a lower multiple correlation.

Relationships between Individual Differences in Strength, Speed, and Mass in an Arm Movement

Abstract According to physics, the equation F = 2 md/t 2 determines the force F required to move a mass m through a distance d in t seconds. Two experiments were performed on college men (n = 35 and 30) in which a lateral arm movement of approximately 90 deg. involving about 4 ft. of hand travel, was made at maximum speed. The movement time t, the effective arm mass m, and the static dynamometer strength s of the muscles were measured for each subject. The reliability of individual differences in all measures was above .96. There was no significant correlation between static strength and “strength in action” computed from arm mass and speed of movement. The results agree with the concept that strength as ordinarily measured is determined by a neuromotor coordination pattern rather than the ultimate physiological capacity of the muscle. The neuromotor pattern energizing the muscle is different during movement. Absence of correlation is another example of the high specificity of neuromotor coordination skil...

Prediction of World Records in Running Sixty Yards to Twenty-Six Miles

Abstract Previous attempts to formulate the mathematical relationship between velocity and elapsed time (or distance) in running records have failed to account for the sprint events and have been empirical rather than theoretical. In the present study, a velocity equation is developed which consists of the sum of three exponential terms having fatigue constants or ks characterizing the muscle energy supply systems—the alactate and lactate oxygen debts and the glycogen reserve. A subtractive exponential term represents the acceleration factor in the sprints. Using this equation, record speeds for 100 yds. and longer distances are predicted with an error of less than 1 per cent; for the 60 meter—60 yd. sprints, with errors of 2 and 3 per cent.

Stimulus Complexity, Movement Complexity, Age, and Sex in Relation to Reaction Latency and Speed in Limb Movements

Abstract Reaction latency and time required for basic limb movements made at maximal speed were measured in 402 subjects including both sexes and several ages within the range 8–30 years. Variation of stimulus type and complexity as well as movement type and complexity had no influence on the amount of correlation between reaction and movement times. Neither age nor sex influenced the amount of correlation, which was close to zero under all conditions even though reaction and movement time reliabilities were high. It was shown that differential conditions of “set” and/or other factors could cause the appearance of correlation. Women reacted slower than men, but the difference (less than .01 sec.) was considered unimportant. They averaged 22 percent slower in movement time than men. Subjects less than 18 years of age reacted and moved slower than adults.

Neuromotor Specificity and Increased Speed from Strength Development

Abstract Arm strength, effective arm mass, and speed in a lateral adductive arm movement were measured in 62 college men and remeasured ten weeks later. During this interval, half of the subjects were given weight training exercise that did not involve the movement, while the other half remained inactive in order to provide a control group. The average of the training group improved significantly in speed, strength, and strength/mass ratio, whereas the average of the control group declined. There was no correlation between individual differences in speed and strength/mass ratio, but individual changes in the ratio correlated significantly (r = .405) with individual changes in speed. Reaction time was not improved by weight training.

Factorial Structure of Speed and Static Strength in a Lateral Arm Movement

Abstract Speed of movement in a lateral adductive arm swing was timed at seven equidistant points on an arc of 120 degrees. Static strength and effective arm mass were measured in the movement position. Data obtained on 36 men and 36 women were subjected to a centroid factor analysis. The structure for both sexes consisted of a single common factor for arm speed and a substantial item-specific factor for the first 17 cm. of movement, suggesting that the velocity curve probably consisted of two components. The correlations between the strength/mass ratios and speeds of movement were almost zero, except in the middle phase of the action, where the relationship was .29 for men and .27 for women (.36 and .34 when corrected for attenuation). These very low correlations supported the hypothesis of neuromotor specificity. Circumferential speed for women was 17 percent slower than for men, partly because their arms were shorter. In angular speed, the sex difference was only 5 percent.

Influence of Motor and Sensory Sets on Reaction Latency and Speed of Discrete Movements

Abstract College men and women were tested as to reaction time and speed of an arm movement using both motor-oriented and stimulus-oriented set. The results confirmed a hypothesis based on neuromotor coordination theory that predicted slower movement and greater reaction latency when the motor set was used. However, the 20 percent of subjects who had a natural motor set tendency moved faster with an enforced motor set than with an enforced sensory set. The conditions of enforced set caused a moderate positive correlation between reaction and movement times. Women subjects reacted and moved slower than men, but were similarly influenced by the two enforced set conditions. Their natural set tendency was definitely stimulus-oriented, while men tended to have a neutral orientation.