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Georgiy Korobeynikov
Introduction
The aging changes of psychophysiological functions are
very serious and multifactorial. Modern gerontological research
shows a decline in the sensory-motor reaction, deterioration
of information processing and perception as well as reduction
of mental capability with aging (Katzman, Tarry, 1983, Arlinger,
1989; Carella, 1990, Monk, 1990, Arbuckle, Conney, Milne &
Melchior, 1994 ). However, the age-related decline of perception
and information processing leads to an increased fatigue and
deterioration of the cognitive functions, especially memory
and thinking (Gallagher T.J., Wagenfeld M.O., Baro F., Haepers
K.,1994; Falkenstein, Hohnsbein, Hoorman, 2000).
At the same time, the following physiological adaptation
reactions arise which prevent the aging process. The adaptation
theory of aging is based on this concept (Frolkis, 1989-1993).
According to the terminology for aging development, proposed
by Frolkis (1993), the whole period of human development from
fertilization to human death can be viewed as the etagenesis,
which includes ontogenesis, mezogenesis and geterontogenesis.
One may assume that perception and informational processing
capability in the aging people are determined by the balance
between aging and vitauct processes (life extension). Unfortunately,
studies on the visual perception and informational processing
capability in aging are lacking.
Methods
Human subjects (80 males and 90 females) belonging to
the three age groups (30-39, 40-49 and 50-60 years) were examined.
The visual perception and information processing were studied
by a special computer test with three algorithm changes.
First algorithm.
Four digits (from 0 to 9) are presented on the computer's
monitor randomly. The subjects were requested to perform a
combination digit test, the task was to calculate (in mind)
the number of digits transposed on the display. The aim of
each presented digits road was to transpose in the increasing
order.
For example:
5 2 3 4 -initial order
2 5 3 4 - first transposition
2 3 5 4 -second transposition
2 3 4 5 - final transposition, the result.
Thus, the result of this task consists of "3" transpositions
which need four digits on the display in the increasing order.
To answer, a person must press the computer's key "3".
Second algorithm.
Four digits (from 0 to 9) are presented on the computer's
monitor randomly. The subjects were requested to perform a
combination digit test, the task was to calculate (in mind)
the number of digits transposed on the display. The aim of
each presented digits road was to transpose in the decreasing
order.
For example:
0 4 7 8 -initial order
0 4 8 7 - first transposition
0 8 4 7 -second transposition
8 0 4 7 -third transposition
8 0 7 4 -fourth transposition
8 7 0 4 -fifth transposition
8 7 4 0 -final transposition, the result.
Thus, the result of this task consists of "6" transpositions
which need four digits on the display in order to calculate
(in mind) the number of digits transposed on the display in
the decreasing order. To answer, a person must press the computer's
key "6".
Third algorithm.
Seven digits (from 0 to 7) are presented on the computer's
monitor randomly. In each figure, one digit is absent. The
subjects were requested to find a missing digit among the
following seven digits.
For example:
0 4 7 6 5 1 2
The result of this task consists of digit "3",
which is missing in this row. To answer, a person must press
the computer's key "3".
The time and the accuracy of performing each assignment were
registered for each person. The duration of a whole informational
process was 9 minutes (3 minutes for each test). The used
model of visual perception and informational processing was
submitted as part of the computer's system of psychophysiological
capacity diagnosis (Polyakov, Burov, Korobeinikov, 1993).
Based on the testing results, the following psychophysiological
parameters were determined: attention volume (AV) and operational
thinking coefficient (OT):
AV = (Nr / N)* 100% (1)
where
Nr - the number of tasks performed successfully,
N - the number of all tasks performed.
OT = (Nr / T)* 100 (2)
where
T - average time of solving a test problem (msec).
100 - coefficient.
For the evaluation of time perception, we used a modified
"individual minute" test proposed by Halberg, 1978
(time perception error, 
T).
The memory function was determined by using a method for
measuring short-term memory volume (MV), which consists in
estimating the correctly memorised digits among twelve two-digit
figures presented for a subject on a display within 30 s.
The use of traditional statistical methods analysis for study
of the visual perception and informational processing capability
in aging was insufficient. The application of informative
mathematical methods to the study of these processes was more
correct. The information processing was studied by informative
mathematical methods. According to entropy of systems by C.Shannon,
(1948) and Glushkov V. (1974), Glushkov has proposed the self-organisation
theory. One of the major parameters of the system organisation
(as a reflection of the information processing) is the following
organisation measure:
(3)
where
R - measure of system organisation (by Glushkov, 1963);
H - current entropy;
Hm - maximum entropy.
The current entropy was determined by Shannon C.:
(4)
where
Pi - probability of i-state system;
n - number of system states.
Probability of i-state system in informational processing
was determined:
(5)
where
Nc - number of correct information processing;
N - number of total information processing.
Maximum entropy was determined:
Hm = log n, (6)
The number of system states for visual information processing
was determined as maximum number of one information processing
stimulus (according to first and second algorithm n = 6N,
for third algorithm n = N).
Results
The results of the study are presented in Table 1. It is seen
from the table that average data on the attention volume (AV),
short-term memory volume (MV), and operational thinking (OT)
are higher in men than in women. The time perception error
( T) is
greater in women vs. men. These data indicate the better cognitive
functioning in terms of perception, attention, memory and
thinking in men compared to women. The values for aging differences
between study parameters (AV, MV and OT) are lower in male
subjects aged 50-60 in comparison with their 30-39-year old
counterparts (p<0,05). The statistically significant differences
are seen in OT values between 40-49- and 50-60-year old male
groups (Table 1).
This circumstance points to the age-related decline in visual
perception and informational processing capability in men.
The dynamics in women differs from that of men. The statistically
significant differences between 30-49- and 50-60-year old
female groups are observed for the OP and T values (p<0,05).
The AV is decreased at age range 50-60 compared to 40-49 (Table
1).
No differences concerning the OT are seen between women in
groups aged 30-39 and 40-49 years (Table 1).
Table 1
Psychophysiological parameters in different age and sex groups
* - p < 0,05 compared to the men;
x - p < 0,05 compared to the previous age group.
Thus, aging is associated with the reduction of psychophysiological
functioning, visual perception and informational processing
capability in women, but these changes have not appeared to
be statistically significant in men, especially between age
groups 30-39 and 40-49.
The information processing has the probability of change in
the input parameters, if we understand the organisation as
an entropy system from chaos to higher determinism (Shannon,
1948). To study these class systems, we used the mathematical
methods from the informational theory (Antomonov, 1969; Glushkov,
1963).
The organisation measure of information processing in different
age and sex groups is presented in Table 2 (men) and Table
3 (women).
Table 2
The organisation measure of information processing in men
of different age groups
*-p < 0.05 compared to the first algorithm;
x - p < 0.05 compared to the previous age group.
The data presented in the above tables show a tendency to
the increase of organisation measure with changing of the
algorithm. This indicates a greater determinism of psychophysiological
organisation during adaptation to visual information processing.
A more simplified information processing structure, which
includes the third algorithm, was defined as the automatically
type. Statistically significant reduction of the organisation
measure in the second algorithm, compared to the first one
(p < 0,05), observable in the male group aged 40-49 years
was the exclusion (Table 2).
At the same time, the organisation measure of information
processing decreased with increasing age as the algorithm
changed. This points to a decrease of the determinism and
an increase of the stochastic organisation of the information
processing system.
The information processing stochastic organisation provides
a search for links, which are needed for the formation of
an optimal level of functional system (Korobeynikov, 1998,
1999). Thus, the stochastic organisation of information processing
system shows one of the forms of adaptation mechanisms, which
prevents aging reduction of mental capability. This conclusion
confirms the adaptation theory of aging proposed by Frolkis
(1993).
Table 3
The organisation measure of information processing in women
of different age groups
*-p < 0.05 compared to the first algorithm;
x - p < 0.05 compared to the previous age group.
However, the organisation measure evaluates the probability
of different psychophysiological states, but it does not evaluate
the operational structure of information processing.
Several authors (Sternberg, 1969, Rotenberg, 1987, Leonova,
1984, Chaichenko, Tomilina, 1994) have established the linear
mathematical relation between time reaction and the number
of correct information processing. The results of this investigation
are opposite to their findings, but they are consistent with
the data of Wickelgren (1977), presenting the speed accuracy
tradeoff as a negative accelerating exponential curve. The
following exponential model reflects the dependence of the
latent time of solution of a test problem on the correct sequence
of tasks to be performed:
Lg Y = a - bX, (7)
or
Y = exp(a - bX), (8)
where
Y - time of solving a test problem (msec)
X - number of tasks performed successfully.
According to the data of Sternberg (1969), Leonova (1984),
Rotenberg (1987), Chaichenko, Tomilina (1994), coefficient
a corresponds to the protraction of information processing
(perception, processing and motor reaction). Table 4 depicts
a coefficient a of a mathematical model information processing.
The changes of task algorithm result in the decline of coefficient
a. This dynamics corresponds to the increase of determinism
of information processing organisation.
Thus the reduction of perception and visual information processing
protraction is connected with strength of psychophysiological
organisation determinism.
The increase of visual information processing protraction
reflects the weakening of psychophysiological organisation
determinism with age.
According to the concept of short-term memory activity (Sternberg,
1969, Leonova, 1984, Rotenberg, 1987, Chaichenko, Tomilina,
1994), the information processing has two strategies of response
organisation.
The first strategy - successive comparison of positive elements
in short-term memory and test information by exhaustive quest.
When it is necessary, long-term memory for comparison of information
can be used.
Table 4
Coefficient a of mathematical model information processing
with change of the algorithm in different age and sex groups
The second strategy - processing by self-finishing quest
with a comparison between positive elements of short-term
memory, in accordance with the element in test information.
The first strategy of response organisation is more efficacious
than the second one, but it has higher protraction of one
information processing stimulus. Due to the increase in the
number of erroneous responses and the repetition of information
processing stimuli, the second strategy will have a longer
protraction of the information processing.
number of tasks
Table 5
Average time of solving a test problem and number of tasks
performed successfully in different age and sex groups
*-p < 0.05 compared to the first algorithm;
x - p < 0.05 compared to the previous age group.
Thus our data confirm the conception of short-term memory
processing (Sternberg, 1969; Band Guido, Kok, 2000). Table
5 depicts the average parameters of efficacy of visual perception
and information processing capability of different age and
sex groups. As it is seen in Table 5, the visual perception
and information processing capability depends on the strategy
of response organisation.
The strengthening of determinism of information processing
organisation under the influence of algorithm changes was
observed in age group 30-39 (Table 2, 3). The information
processing by exhaustive quest is present in this age group
(Table 4). The increase of visual perception and information
processing capability results in such response organisation
(Table 5).
The acceleration of involution process in age group 40-49
results in decline of the perception and information processing.
At the same time, the decrease of determinism of information
processing organisation is shown with the first algorithm
performed in women and with second and third algorithms performed
in men. There are changes of response organisation strategy
by self-finishing quest along with reduction of protraction
of one information processing stimulus in women group 40-49
(Table 4).
The result of this response organisation shows the stabilisation
of visual perception and information processing capability
(Table 5). Besides, there are no statistically significant
differences between women age groups 30-39 and 40-49 for parameters:
attention volume, short-term memory volume and operational
thinking coefficient.
The increase of stochastic organisation of visual information
processing has been seen in age group 50-60 (Table 2 and 3).
This finding corresponds to the strategy of self-finishing
quest response in short-term memory, in accordance with the
elements of test information. However, the number of correct
processing stimuli decline with not reliable changes of the
average time of solving a test problem in age group 50-60
(Table 5). At the same time, no changes in the operational
thinking coefficient between female age groups 40-49 and 50-60
have been found (Table 1).
Discussion
In our previous studies the concept of psychophysiological
stochastic organisation in the mental activity was substantiated
(Korobeynikov, 1998,1999,2001). According to this concept,
the psychophysiological stochastic organisation is a mechanism
for the quest of optimal mental activity. In the process of
aging involution, the adaptative-compensatory mechanisms of
decline of visual perception and information processing capability
protection get activated. One of these mechanisms is linked
with the psychophysiological stochastic organisation.
With age-related decline of perception and information processing
intensifies tension of the informational environment on older
people. As a result of the negative influence of aging, the
efficiency of the mental activity reduces. Decrease of the
visual perception and information processing capability with
age triggers a compensation of the psychophysiological adaptive
mechanisms with the change of an algorithm. The key mechanism
consists in the increase of the stochastic organisation of
information processing and change of the information processing
structure into a self-finishing quest response.
Strengthening of the determinism organisation of information
processing reflects an aging advancement and a decline of
cognitive functions, particularly the operational thinking.
The study has revealed a tendency to the increase of determinism
organisation along with the simplification of information
processing structure. The reduction of information processing
protraction is related with the high determinism of psychophysiological
organisation.
Increase of the determinism of information processing organisation
and change of the information processing strategy reflect
the psychophysiological mechanisms of life extension in the
aging involution of cognitive functions.
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Institute of Gerontology, Vyshgorodskaya
St. 67, 04114 Kiev, Ukraine; fax:+380-44 432 9956; e-mail:
admin@geront.kiev.ua
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