1584 Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013
Journal of Food, Agriculture & Environment Vol.11 (3&4): 1584-1591. 2013
Science and Technology
Meri-Rastilantie 3 B, FI-00980
Received 12 July 2013, accepted 22 October 2013.
Human emotional and psycho-physiological responses to plant color stimuli
Mohamed EL Sadek 1*, 2, Sato Sayaka 1, Eijiro Fujii 1, Eid Koriesh 2, Eman Moghazy 2 and Yehia Abd El Fatah 2
1Graduate School of Horticulture, 648 Matsudo Matsudo-shi Chiba 271-8510, Chiba University, Japan.
2Department of Horticulture, Faculty of Agriculture, 41522, Suez Canal University, Egypt. *e-mail: firstname.lastname@example.org
Studies have shown that plants have both physiological and psychological benefits for people. Such studies have investigated the value of plants or
flower colors in human being, but they typically have not considered how the color might also influence eye movement, emotional status and brain
activity of the individuals.This study focused on the relation between plant variegation and human psycho-physiological functioning. Twenty-nine
undergraduate students (14 males and 15 females) participated in this study to measure their psycho-physiological responses to five different foliage
colors of Hedera helix L. Each plant was presented for 60 s in no particular order. During the exposure time eye movements were recorded by eye
mark recorder as well as 47 channels of near-infrared spectroscopy (NIRS) were used to measure the brain activity in the frontal, temporal, parietal
and occipital lobes. The participants were asked to describe their impressions towards each plant category on a five-point scale based on the semantic
differential questionnaire (SD). The results showed that the participants pay less attention through eye movements for the common and ordinary
colors. The cerebral blood flow (CBF) increment was correlated with the degree of attention settled by the participants to the visual. The results also
revealed variant responses for each color in both eye movements and brain activity. Moreover each color correlated with some emotional responses,
thereby each color is recommended for specific situations. The outcome may have some practical applications to the environment. The dark green
colored plants can be used to make a place more relaxing and calming. While the green-yellow and bright green colored plants can be used to make a
place more pleasant, exciting and brightness additionally, they increase a sense of strength. On the other hand, the red plants can be used in a place
where high concentration are required and to create a luxurious environment.
Key words: Plant variegation, Hedera helix, brain activity, eye movement, SD, emotional response.
Experimental studies have confirmed that positive emotions have
a beneficial effect on human health. For example, Davidson and
colleagues have shown that individuals with a positive affective
style have a higher level of immune function than those with a
negative affective style 1. Also, it has been known for a long time
that negative emotions are related to a higher prevalence and
severity of disease. Recent evidence has suggested that certain
types of plants promote emotional stability in human, as by
facilitating psychological calming, reducing stress, fatigue, etc 2.
Meanwhile, the belief that plants are beneficial for people in
healthcare environments is more than one thousand years old
and appears prominently in Asian and western cultures 3.
Additionally, during the middle ages in Europe, monasteries
created elaborate gardens to bring pleasant feeling and promote
healing 4. People have begun to use plants to decorate the office
environment since the 1960s 5. A number of studies have
investigated the effects of indoor plants on outcomes relevant to
effectiveness and well being of office workers. Lohr et al. 5 and
Nakamura and Fujii 6 reported that stress-reducing responses occur
when people are in a room with interior plants added, showing
that plants alone could evoke the response. Moreover, Hartig et
al. 7 and Ulrich et al. 8 found that subjects viewing nature settings
dominated by vegetation or natural scenery showed relief from
stress, mental fatigue and had lower levels of fear and anger in
contrast to those who were shown movies with urban settings.
The effects were evidenced by positive changes, for instance,
lower blood pressure, muscle tension, and skin conductance. Most
of the above studies have examined the visual effects of natural
landscape or interior plants on individuals. So far, however, only
very limited studies have specially investigated the influence of
plant colors on human responses, although, color is an inseparable
part of our everyday lives, and its presence is evident in everything
we perceive. Additionally, it is widely recognized that colors have
also a strong impact on human emotions and feelings 9-11.
Moreover, some colors may be associated with several different
emotions and some emotions are associated with more than one
color. For instance, Saito 12 found that the color black elicited both
negative and positive responses among Japanese participants,
and the black was often a preferred color among young people.
Recently, researchers have shown an increased interest in
examining flowering plant color preferences and their effects on
human perception. Behe et al. 13 examined the effect of flower
color on the choice of plant. The results showed that red and
lavender flowers were preferred over white and pink ones.
However, a simulated blue flower color was preferred least of all.
Additionally, Todorova et al. 14 examined color preferences in
street plantings. They concluded that users preferred flowers with
bright colors. More recently, some researchers have reported on
observed psycho-physiological effects of plant colors. Li et al. 15
examined people responses to different colors and the data
Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013 1585
suggested that green and purple plantscapes appear to be more
effective in relaxing the body, reducing anxiety and improving
mood, compared with red, yellow, and white plantscapes. Also, a
number of studies have reported that green plants are useful for
improving cerebral activity and creating a comfortable
environment16, 17. Although people receive information from the
environment through five senses, it is estimated that for the sighted,
more than 70% is derived through visual perception18. Eye
movements, which provide the simplest and the most accurate
way to extract information from the participant’s visual
environment, largely determine which of the selected information
is due for further processing 19. Meanwhile, eye movement should
be an indicator of humans’ psychological status 20. As the visual
information perceived by the eyes is conveyed to the brain, the
aim of this study, therefore, was to investigate the impacts of
colors on eye movements and brain activity is being actively
pursued in order to determine color effects on human psycho-
physiological responses. Although plant colors have been largely
unexamined, as colors have to stimulate positive feelings,
variegated plants might well be able to stimulate desire responses
of promoting calm and relaxation. Therefore, we seek to a more
thorough explanation for human psycho-physiological changes
in response to a range of different plant colors, by means of testing
eye movements, cerebral blood flow (CBF) and administering
semantic differential questionnaire (SD) to participants. The effects
of the colors on responses of males versus females were also
compared. The findings presented here help provide a better
understanding of the human visual cognitive responses to
different foliage colors. Furthermore; the findings may be useful
in helping indoor landscape designers to determine the most
suitable plant color for a particular environment.
Methods and Materials
Participants: Twenty-nine healthy right-handed volunteered
undergraduate students (14 males and 15 females; aged 19-24
years) with normal or corrected-to-normal visual acuity and no
history of neurological illness were recruited for the study. Each
subject was asked to sign a liability consent form and was given
a brief outline of the proceedings of the experiment without
identifying which plant colors would be used in the experiment.
The study was conducted in accordance with ethics rules of Chiba
Visual stimuli: In order to present different plant colors stimuli of
the same shape to the participants (to distinguish color effects
only), five varieties with different foliage colors of Hedera helix
L. (English ivy), which include Pittsburgh (dark green), glacier
(green-white), gold child (green-yellow), light finger (bright green),
and Pittsburgh (red) were selected (Fig. 1). Twenty-four samples
of each plant were put into one tray with the dimension of 60 x 40
cm2 in order to make a group and to show it as one for each plant
color (Fig. 2). A tray without plant was displayed for 1 min before
each plant category as control.
Psycho-physiological measurements: Eye tracking and eye
fixation were recorded using an Eye Mark Recorder with the cornea
and pupillary reflex method (EMR-9, NAC Image Technology Co.,
Ltd. Japan). Fluctuations in cerebral activity resulting from the
visual stimuli were measured by multichannel near-infrared
Figure 2. Experimental setting, measuring brain activity and eye
movements recording during exposure to stimuli.
Figure 1. Hedera helix L. varieties used in the experiment
as visual stimuli.
spectroscopy (NIRS; OMM-2001; Shimadzu Co., Ltd., Japan).
NIRS directly monitors regional relative changes of hemoglobin
concentration in the cerebral blood flow (CBF) 21. This method
requires only compact experimental systems but is less restrictive,
allowing the subject to freely move in his seat, unlike functional
magnetic resonance imaging and positron emission tomography
testing which require subjects to remain in a supine position 22, 23.
Measurement was limited to the right hemisphere of the brain
only due to its control over emotion and image creation 24, 25. Forty
seven measurement locations, referred to as channels (ch)
were located in the frontal, parietal, temporal, and occipital
lobes (Fig. 3). These brain locations correspond with feeling,
judgment, premotor, motor, somatosensory, cognition, visual,
auditory, and memory functions 26, 27.
The direct impressions evoked by the plant color were examined
via the questionnaire using semantic differential (SD) methods,
which have been found to be a reliable and valid way to quantify
subjective feelings about external stimuli 28-30. In this study, 17
pairs of contrary adjectives were used, designed to rate the
participants’ feelings and impressions on a five-point scale from 1
(most positive) to 5 (most negative) 17, 31.
Experimental setting and procedure: The participants were
tested individually in an electromagnetic shield room at Chiba
University, with keeping the external factors such as temperature,
relative humidity and light consistent. The room had no windows.
Participants were first instructed by the experimenter about the
1586 Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013
Figure 3. Localization of functions in the brain. According to the
theory of localization of the brain function, 47 channels
corresponded with feeling (ch1, 3), judgment (ch2, 4, 5, 6, 8, 9),
premotor (ch7, 11, 12, 16), motor (ch13, 17, 18, 20, 21),
somatosensory (ch22, 25, 26, 27, 29, 30, 31, 34, 35), memory
(ch15, 19, 23, 24, 33), cognition (ch38, 39, 40, 41, 43), visual
(ch42, 44, 45, 46, 47), auditory (ch28, 32, 36, 37), and speech
(Broca, ch10, 14) functions.
procedure and how the instruments will be used, while helping
the participants to adapt to the experimental environment. They
were also instructed to turn off mobile phones. An informed
consent was signed, stating they could withdraw from the
experiment at any time. The participant sat on a comfortable chair
in the most comfortable position 50 cm away from the tested plants
(Fig. 2). The psycho-physiological recording devices were placed
behind the participant to minimize interference from the
instruments. During each trial, the NIRS electrodes and eye
movement’s detector were installed to the participant. The
measuring conditions of cerebral activities were checked, and
calibration for eye movement was carried out. The participant was
instructed to relax and close his eyes and limit his movement.
While the participant rested with his eyes closed, the first plant
category was placed on a table covered with a black cloth at the
participant’s eye level to ensure a straight line of the sight of the
object without having to move his head. Then the examiner asks
the participant to open his eyes. The CBF and eye movements
were recorded for 60 s, after being asked to close eyes again.
Afterwards the other categories took place and the sequence was
repeated with each category. After completing the psycho-
physiological measurements, the participant was asked to fill out
the SD questionnaire for each plant color separately. Order of the
plants presentation was randomized across the participants. The
total procedure lasted approximately 40 min for each participant
Figure 4. Sequence of color exposure and associated experimental events. The 29 subjects were
measured individually. Each plantscape color was presented in random order during the experiment.
Data analysis: The number of eye fixations is the visual points
fixed on 0.2 s or longer on the visual stimulus. This is based on the
fact that more than 0.2 s is required to consciously recognize the
stimuli 32 and eye fixation durations for 1 min after exposure to the
visual stimuli were analyzed by EMR-dFactory ver. 2.0. Steel-
Dwass multiple comparison tests were used to statistically compare
responses among the tested plants.Regarding CBF, the data were
analyzed separately for each channel (ch). The cerebral changes
during exposure to the plant categories were examined by
comparing the means of each 30-s interval starting with the last 30
s of the rest period before plant presentations. This was assumed
to represent the most stable states of the brain and physiological
activity during the rest period. A paired t-test (two-sided) was
used to compare the physiological changes between rest and
exposure periods. The cerebral activity analysis used fluctuations
in oxygenated hemoglobin (oxy-Hb) as the index of cerebral
changes, where increased oxy-Hb is associated with increased
cerebral activity. The changes were separately computed in 47
measurement locations of the brain. The Wilcoxon signed rank-
sum test (two-sided) was used to verify the differences in
psychological effect assessed by the SD scale. SD data were
analyzed by comparison of rating scores among the tested plants.
Statistical validation of psychological, physiological data and
verbal evaluation were established at P < 0.01 and p < 0.05, P <
Results and Discussion
Eye movements: As can be seen from Figs 5 and 6, fixation
durations and numbers of eye fixation were affected by the plant
categories. Male participants data show a significant difference
between green-white and dark green plants (P = 0.0403). These
results reveal that the green-white plant tended to generate longer
fixations duration of eye movement compared with the dark green
plant. Concerning, eye fixation number, there was a significant
difference between the same two plants (P = 0.0820). Results from
the current study indicate that male participants carefully observed
the details of the green-white plant as evidenced by long fixation
duration and higher fixation numbers of eye movements compared
with their responses to the dark green plant.
With regard to female participants, no significant differences
were found among the tested plants with respect to eye fixation
durations. Whereas, regarding eye fixation number there were
significant differences between green-yellow and dark green (P =
0.0359), and also, between green-yellow and green-white (P =
0.0067). These results reveal that female participants carefully
observed and saw the details of the green-yellow plant to a greater
extent than the dark green or green-white species.
Although the view of plant varieties is fairly similar, different
results in eye movements were obtained.
It means that different colors or variation
in color makes some plant type less
attractive, as in the case of the dark green
plants evidenced by lower fixation number
and shorter duration of eye movements
among the male participants, while other
types appear more interesting, attractive
or fantastic as in the case of green yellow
plant for the female participants. Longer
fixations are usually associated with extra
Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013 1587
Number of eye fixation
Dark green RedBright greenGreen-yellowGreen-white
Figure 5. The number of eye fixation among Hedera helix varieties
for 60 s when the subjects (males and females) are viewing the
cognitive demand, informative visual information at the fixated
region, and/or display complexity 33-35. Broadly, longer fixation
durations and higher fixation number of eye movements revealed
that the participants spend more time for interpreting those visual
stimuli 36, 37. The extra fixation duration on the plants may be
correlated with the detailed analysis of color features.
Impression evaluation: Fig. 7 presents the results of
psychological survey of the responses to the 17 pairs of emotional
words that were provided in association with the stimuli of the
five foliage plant varieties. The results reveal that people do have
different responses for different colors. Based on the results
obtained from the males’ responses, the dark green plant was
ordinary, natural and common color for the participants;
furthermore it induced feelings of stability and calmness. However,
the green-white plant was associated with the lowest number of
positive responses because it was evaluated as being pale, weak,
Eye fixation duration
Figure 6. Comparison of eye fixation duration among Hedera helix varieties
for 60 s after exposure to visual stimuli.
cool and passive. On the other hand, green-yellow and bright
green plants were generally seen to be bright and showy and
to elicit positive emotions including happiness and strength.
Furthermore, participants felt more active in the presence of
the bright green plant. Similar results have been reported in
studies by Todorova 14 and Boyatzis 38 which concluded that
bright colors such as bright green and yellow had the highest
positive effects for people. On the other hand, the red plant
was highly affiliated with the descriptive words characteristic
and bringing out the feeling of warmth.
Regarding female participants, the dark green plant scored
high on the words comfortable and calm furthermore, it was
daily, natural and common color. These results are similar to
those studies 15, 18, which concluded that scenery containing
green plants is strongly associated with feelings of comfort.
As well, the results are in general agreement with the findings
of Saito 12 whose subjects found green material to be refreshing
and beautiful. Reasons given for positive responses to green
showed that green was associated with nature, grass, trees,
and would remind the viewers of outdoors and springtime,
responses consistent with Hemphill’s 9 findings. On the other
hand, while the green-white plant evoked a feeling of weakness,
in contrast, it had the highest rating as evoking a feeling of
spaciousness. This is an important finding for anyone who is
contemplating cultivating indoor plants and who may be
concerned about the spatial implications. The green-yellow
plant was seen to be showy, bright, active, strong and elicited
positive emotions including happiness. While, the bright green
plant stimulated feelings of being bright, cheerful and exciting.
The red plant prompted both positive and negative emotional
reactions; it was seen to be positive because it was associated
with characteristic, active and warm, while the negative aspects
of red included evoking feelings of unsteady, unquiet and
uncomfortable. Overall, therefore, the environments containing
dark green, green-yellow or bright green plants were found to
stimulate positive feelings such as calmness, brightness,
cheerfulness, activeness, and being beautiful and exciting, as
compared with green-white or red plantscape. The findings of
the current study are consistent with those of Hye et al. 17 and
Lee and Son39, who found that visual stimuli with yellow and
green slides induced feelings of steady, cheerful and increasing
the brightness of the environment. However, the red plant
provided feelings of warmth and activity, and created a luxurious
environment, findings that are comparable with the results of Hye
et al.17. Thus, we are able to conclude that plants with different
colors could be selected for use depending on the environmental
demands to create various styles of relaxing, pleasant and/or
The difference between impressions of both genders: It is clear
that there is a similarity between male and female participants’
responses except in some limited cases such as the dark green
colored plant evokes the feelings of activeness and brightness
for males more than females. Additionally, the white-green colored
plants stimulate the feeling of roomy for female more than male
participants. Furthermore, males had a sense of strength and
activity in the presence of the bright green colored plants more
than females. The red colored plant is showy, daily and depressed
for female more than male participants. On the other hand it was a
1588 Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013
Dark green RedGreen brightGreen-yellowGreen-white Dark green RedGreen brightGreen-yellowGreen-white
Figure 7. Semantic differential scale used by 29 Japanese students, males (left) and females (right), to describe Hedera helix verities.
favorite of males more than females. The color green elicited mainly
positive emotional responses, including the feelings of relaxation,
calmness as well as stable, comfort, daily, and natural.
Changes to cerebral activity by vision: Fig. 8 demonstrates the
brain activity and shows the channels where significant
fluctuations in oxy-Hb were observed by viewing the different
plant colors for male and female participants.
Male participants: While male participants were shown the dark
green plants, the cerebral activity was significantly sedated in the
feeling area (ch1, P <0.01), and the judgment area (ch2, P <0.01),
which controls concentration, attention and interest. These results
suggest that the dark green plants are effective in promoting
relaxation evidently by the oxy-Hb sedation at the feeling area.
The results of these data are in harmony with those of Hoshi et
al.40 that pleasant emotion was followed by decreasing levels of
oxy-Hb at two channels placed around the right ventrolateral
Figure 8. Changes in oxygenated hemoglobin (oxy-Hb) at the brain by vision of each color of Hedera helix for male
and female participants.
, Significant increases in oxyhemoglobin concentration at P<0.01; , significant increases in oxyhemoglobin concentration at P<0.05; , significant increase in
oxyhemoglobin at p<0.10; , significant decrease in oxyhemoglobin concentration at P<0.01; , significant decrease in oxyhemoglobin concentration at P<0.05; ,
significant decrease in oxyhemoglobin at P<0.10.
Dark green Green -white Green-yell ow Brigh t green Red
prefrontal lobe. Furthermore, Davidson and his colleagues 41
reported that induced positive and negative affective states shift
the symmetry in prefrontal brain electrical activity; with negative
affect increasing relative right-sided activation and positive affect
increasing relative left-sided activation.
On the other hand, during the stimulation with the green-white
plants, the cerebral activity was significantly sedated in the
judgment, memory and visual areas (ch9, ch23 and ch47, P <0.05,
respectively), as well as the motor area (ch13 and 18, P <0.05, P
<0.10, respectively). In contrast, the CBF was notably increased
in somatosensory area (ch31 and ch 35, P <0.10), which is strongly
associated with body senses, being responsible for processing
sensory information such as smell, taste, touch, vision, and sound.
Furthermore, the CBF was activated in the cognition area (ch38, P
<0.10 and ch40, P <0.05) which controls object recognition. In
contrast, the stimulation with the green-yellow plants showed
activity in brain areas including the motor area (ch17, P <0.01)
which controls muscles on the left side and the cognition area
Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013 1589
(ch40, P <0.05), while the cerebral activity was sedated in the
memory area (ch19, P <0.10) which controls emotional memory.
However, once the participants glimpsed the bright green plants,
the cerebral activity was sedated in the motor area (ch13, P<0.01),
while it was increased in cognition area (ch40, P<0.05). When
participants were shown red plants, cerebral activity was activated
in the judgment area (ch4, P<0.05) and cognition area (ch41,
P<0.10), but was sedated in the memory area (ch19, P<0.05). The
red plant had the opposite effect of triggering a more relaxed
evidently by the activation in the judgment area that controls
concentration and attention. It is apparent that the CBF was
activated in the cognition area while participants were viewing
green-white, green-yellow, bright green and red plants. However,
in the presence of the green-white, the CBF was sedated in the
visual area which integrates visual information, giving meaning
to what is seen by relating the current stimulus to past experiences
and knowledge. The current results are generally consistent with
those of Phan et al. 42 and Reiman et al. 43 that in the lateral surface
of the hemispheres, the oxy-Hb in the occipital cortex responsed
to visually evocative stimuli, but activation in the area was
independent on the type of emotion.
Female participants: Female participants showed some different
patterns of cerebral responses compared with males when viewing
the same plant colors. When female subjects were viewing the
dark green plants, the cerebral activity was activated in the premotor
(ch12, P <0.01) and cognition areas (ch40, P <0.05), while it was
sedated in the somatosensory area (ch31 P <0.10). In addition,
when the participants were viewing the green-white plants, the
cerebral activity was sedated in the somatosensory area (ch26, P
<0.05, ch27 and ch30, P <0.10) which controls body senses on the
left side as well as face, lips and tongue sense, and the vision area
(ch47, P <0.05) which involves specifically in perception of color
and vision motion, however, the cerebral activity was activated in
Activation of brain blood flow, sedation of brain blood flow
Table 1. Relationship among eye movement, impression response and brain activity in
the presence of the plantscape colors.
the judgment area (ch9, P <0.10). Regarding the green-yellow plant,
when the participants were viewing it, the cerebral activity was
significantly activated at the premotor area (ch16, P <0.05) which
is especially important in the conditional motor tasks and controls
motor and movement skills, and in the somatosensory area (ch27,
P <0.10) which controls the sensation of the body and skin, while,
it was sedated in the memory area (ch15, P <0.01). In the case of
the bright green plant, the cerebral activity was limited, only
activated in the motor area (ch20, P <0.10). Finally, when the
participants were viewing the red plants, the CBF was activated
at the premotor (ch7 and12, P <0.10) and motor areas (ch17, P
<0.10). In contrast, it was sedated in the judgment, somatosensory
and auditory areas (ch2, 27 and28, respectively, P <0.05), in addition
to the auditory area (ch36, P <0.10).
Relationship among eye movement, impression response and
brain activity of the participants in response to plant colors:
The results of the relationship among eye movement, emotional
status and brain activity in the presence of the plant color stimuli
are summarized in Table 1. The results of this study support those
of the previous studies and confirm that different colors of
plantscape can evoke different responses. It is apparent from this
table that the CBF increment was correlated with the degree of
attention settled by the participants with respect to the visual;
the finding is line with the results of Bondy et al. 44. Also,
somatosensory area activation was found to be linked to the
awareness of visual information, which increased duration and
fixation of eye movements, a finding similar to results reported by
Kleiser et al. 45 and Rees 46. When male participants viewed the
dark green plant, lower fixation numbers and shorter fixation
durations of eye movement, along with sedation in oxy-Hb in the
judgment area which controls concentration and attention were
observed. This result was possibly because the color is common
and ordinary in the subjects’ daily lives, as evidenced by the SD
survey. These results are consistent
with Ruggieri 47 and suggest that eye
movement when human actively think
about something is much active than
that when human think about something
passively. Furthermore, when the
participants reported calm and relax in
the presence of that plant in the SD
survey, sedation was also observed in
the feeling area, which is especially
important in stimulating the feeling of
relaxation. These results support the
view that green plants could be
incorporated further in parks or
hospitals in order to provide relaxing
and restorative surroundings. The
findings of the current study are
consistent with those of Li et al.15 and
Kaufman and Lohr 48 who concluded
that green plantscape was more effective
than other colors in promoting relaxation.
On the other hand, while the
participants reported that the green-
white plants were associated with
negative emotions such as passive, cool
1590 Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013
and weak, it was also observed that the CBF was sedated in the
motor area which controls muscles, in addition to the vision area,
which involves specifically the perception of color and vision
motion. In addition, in this case sedation was observed in the
judgment area, which controls concentration and attention
because the participants judged that the plant was ordinary. Saito12
further explained the possible influence of ancient Japanese
religion and mythology on the Japanese attitude to white. A number
of Saito’s subjects in Taipei expressed a negative feeling toward
white, indicating an association with the image of death. On the
other hand, in the presence of the green-yellow plant, the CBF
was increased in the motor area, as well; the participants reported
that they feel exciting, active and strong. Consequently, yellow
plantscapes could be incorporated in children’s activity areas and
in the office to improve energy and employees’ productivity.
Additionally, when participants felt that red plants are
characteristic and distinctive, it was noted that the plant received
more attention and concentration, as evidenced by the CBF
increment in the judgment area. These results are in accord with
those of Kuller et al. 49 who found that red color put the brain into
more excited state. Therefore, red plants could be used in situations
where high concentration is required, as well as to create a luxurious
environment. Finally it was observed that the CBF was activated
in the cognition area (which involves all aspects of perception,
thinking, reasoning, and remembering) in the presence of all plants
except the dark green one because the participants felt that the
green color was too commonplace. The authors found that the
amount of attention paid during the execution of the task
significantly affected the oxyhemoglobin concentration, thus
providing that the occipital activity can be influenced by attentional
For female participants, nevertheless, dark green plants were
effective in promoting a sense of strength, as evidenced by the
cerebral activation in the premotor area of the brain. According to
the SD survey, the green-white plant was preferred by the
participants overall, and the participants’ impression was
supported by the cerebral activation in the judgment area, which
controls concentration, attention and interest, and the cognition
area which involves all aspects of perception, thinking, reasoning,
and remembering. In contrast, sedation was observed in the
somatosensory area, which is involved in the integration of
sensory information and in the vision area. These results indicate
that green-white plants can diminish the sensation of body or
skin 51. Other SD survey results concern the green-yellow and
bright green plants, both varieties invoking exciting, active and
strong feelings, which was supported by the activation in the
premotor and motor areas of the brain. Finally, while the participants
were viewing the red plants, the cerebral activity tended to decrease
in the judgment, somatosensory and auditory areas. In addition,
this color was associated with the most negative description
according to the observers’ impression; the participants reported
they disliked it. Interestingly, it is apparent that oxy-Hb
concentration tended to diminish in judgement, somatosensory
and auditory areas when the participants were in a state of feeling
unsteady, unquiet and uncomfortable, the impression being of
dislike for the object. There are similarities between the attitudes
expressed by the participants in this study and those described
by Suzuki et al. 52 who examined brain activity during semantic
differential rating of drawing stimuli containing different affective
polarities. They reported that oxyhemoglobin concentration was
lower around the right superior temporal and partial regions and
especially in the somatosensory and auditory areas when subjects
were viewing a noisy or temperamental picture. Recent studies
have demonstrated that the brain is predominantly activated by
unfavorite colors over favorite colors 53. Although, positive and
negative emotions appear to be associated with different styles
of processing information, it is apparent that, in this study, the
brain activation patterns in response to visual stimulation with
favorite and unfavorite colors were different from each other. The
results revealed that the oxy-Hb increased and the brain was
activated in the case of positive emotions and vice versa, pleasant
and unpleasant emotions based on cerebral activity.
The present study was designed to investigate how viewing a
variety of different foliage colors, i.e. dark green, green-white,
green- yellow, bright green and red affects the psychological and
physiological reactions of both gender of Japanese people. The
evidences from this study confirmed that human do different
responses to the presence of different foliage colors. The
participants paid less attention through eye movements for the
dark green plants possibly because it was rated as common color
in their daily life. In the other hand it stimulated the feeling of
calmness and relaxing. In the case of the white plant, it was a
favored for females more than males. Additionally, the yellow color
plant stimulated positive emotions for both genders, however, it
attracted females attention more than males, moreover it increased
the sensation of the body and the skin for females. The red colored
plant created a warmth and luxurious environment, it helped males
to be more concentrated and draw their attentions, on the other
hand, it increased females activity. The outcome is practically
applicable for selecting subjective favorite colors in conjunction
with the interior and living environments. Plant colors can be
used to help people release stress and improve emotional status.
We would like to suggest that landscape and interiorscape
designers pay more attention in choosing foliage colors.
The authors are deeply grateful to all the students who agreed to
participate in the study as volunteers. This research was funded
with a grant from the Egyptian Ministry of Higher Education.
1Rosenkranz, M.A., Jackson, D.C., Dalton, K.M., Dolski, I., Ryff, C.D.,
Singer, B.H., Muller, D., Kalin, N.H. and Davidson, R.J. 2003. Affective
style and in vivo immune response: Neurobehavioral mechanisms.
Proceedings of the National Academy of Science 100(19):11148–11152.
2Lee, G. 2006. Visual preference in green roof sites. J. Korean Inst.
Landscape Architecture 34:32–38.
3Ulrich, R.S. and Parsons, R. 1992. Influences of passive experiences
with plants on individual well-being and health. In Relf, D. (ed.). The
Role of Horticulture in Human Well-being and Social Development.
Timber Press, Portland, OR, pp. 93–105.
4Gierlach-Spriggs, N., Kaufman, R. and Warner, S.B. 1998. Restorative
Garden: The Healing Landscape. Yale University Press, New Haven.
5Lohr, V.I., Pearson-Mims, C.H. and Goodwin, G. K. 1996. Interior
plants may improve worker productivity and reduce stress in a
windowless environment. J. Environ. Hort. 14:97–100.
6Nakamura, R. and Fujii, E. 1990. Studies of the characteristics of the
electroencephalogram when observing potted plants: Pelargonium
Journal of Food, Agriculture & Environment, Vol.11 (3&4), July-October 2013 1591
hortorum ‘Sprinter Red’ and Begonia evansiana. Technical Bulletin of
the Faculty of Horticulture of Chiba University 43:177-183.
7Hartig, T., Mang, M. and Evans, G.W. 1991. Restorative effects of
natural environment experiences. Environ. Behav. 23:3–26.
8Ulrich, R. S., Simons, R.F., Losito, B.D., Fiorito, E., Miles, M.A. and
Zelson, M. 1991. Stress recovery during exposure to natural and urban
environments. J. Environ. Psychol. 11:201–230.
9Hemphill, M. 1996. A note on adults’ color-emotion associations. Journal
of Genetic Psychology 157:275–281.
10Lang, J. 1993. Creating Architectural Theory: The Role of the Behavioral
Sciences in Environmental Design. Van Nostrand Reinhold, New York.
11Mahnke, F. 1996. Color, Environment and Human Response. Van
Nostrand Reinhold, New York.
12Saito, M. 1996. Comparative studies on color preference in Japan and
other Asian regions, with special emphasis on the preference for white.
Color Research and Application 21(1):35–49.
13Behe, B., Nelson, R., Barton, S., Hall, C., Safley, C.D. and Turner, S.
1999. Consumer preferences for geranium flower color, leaf variegation,
and price. HortScience 43:740–742.
14Todorova, A., Asakawa, S. and Aikoh, T. 2004. Preferences for and
attitudes towards street flowers and trees in Sapporo, Japan. Landscape
and Urban Planning 69(4):403–416.
15Li, X., Zhang, Z., Gu, M., Jiang, D-Y., Wang, J., Lv, Y-M., Zhang, Q-
X., and Pan, H-T. 2012. Effects of plantscape colors on psycho-
physiological responses of university students. J. Food Agri. Environ.
16Chang, C-Y. and Chen, P-K. 2005. Human response to window view
and indoor plants in the work place. HortScience 40:1354–1359.
17Hye, S.J., Jongyun, K., Ki, K.S. and Chun, H.P. 2012. Human Brain
Activity and Emotional Responses to Plant Color Stimuli. Color
Research and Application. pp. 1-10, (Consult web page < http://
onlinelibrary.wiley.com/doi/10.1002/col.21788/pdf > for further
18Song, J.E. 2004. Effects of Interior Plantscape in Office on Psycho-
physiological Improvement and Stress Alleviation of Indoor Workers.
PhD thesis, Konkuk University, Seoul, South Korea.
19Merchant, S. 2011. Eye movement research in aviation and
commercially available eye trackers today. Consult web page <http://
Eye_Tracking_Company_List.pdf> for further information..
20Arai, K. and Hasegawa, K. 2013. Method for psychological status
monitoring with line of sight vector changes (human eye movements)
detected with wearing glass. International Journal of Advanced Research
in Artificial Intelligence 2(6):65-70.
21Villringer, A. and Dirnafl, U. 1995. Coupling of brain activity and cerebral
blood flow: Basis of functional neuroimaging. Cerebrovasc. Brain Metab.
22Nakamura, N. 1996. Near-infrared spectrophotometer and the
application. Japanese Journal of Physiological Anthropology 1(2):
23Okamoto, M., Dan, H., Shimizu, K., Takeo, K., Amita,T., Oda, I.,
Konishi, I., Isobe, K.S., Suzuki, T., Kohyama, K. and Dan, I. 2004.
Multimodal assessment of cortisol activation during apple peeling by
NIRS and fMRI. Neuroimage 21:1275–1288.
24Silberman, E. K. and Weingartner, H. 1986. Hemispheric lateralization
of functions related to emotion. Brain Cogn. 5:322–353.
25Tucker, D.M. 1981. Lateral brain functions, emotion, and
conceptualization. Psychol. Bull. 89:19–46.
26Caplan, L.R. 1993. Brain-stem Localization and Function. Springer,
27Shepherd, I.F. 1901. Localization of Brain Function. Kessinger
Publishing, Whitefish, MT.
28Kang, J. and Zhang, M. 2010. Semantic differential analysis of the
soundscape in urban open public spaces. Build. Environ. 45:150–157.
29Lee, J., Park, B., Tsunetsugu,Y., Ohira, T., Kagawa, T. and Miyazaki, Y.
2011. Effect of forest bathing on physiological and psychological
responses in young Japanese male subjects. Public Health 125:93–
30Snider, J.G. and Osgood, C.E. 1969. Semantic Dfferential Technique: A
Sourcebook. Aldine, Chicago, IL.
31Jo, H., Lee, J. and Fujii, E. 2007. Physiological and psychological
effects of Oriental herbs scents based on cerebral blood flow and
semantic differential method. Environ. Inf. Sci. 21:207–212.
32Yarbus, A.L. 1962. Eye Movements and Vision. Plenum (Originally
published in Russian), New York.
33Hooge, I.T. and Erkelens, C. J. 1998. Adjustment of fixation duration
in visual search. Vis. Res. 38:1295–1302.
34Jacobs, A.M. 1986. Eye-movement control in visual search: How direct
is visual span control? Percept. Psychophys. 39:47–58.
35Salthouse, T.A., Ellis, C.L., Diener, D.C. and Somberg, B.L. 1981.
Stimulus processing during eye fixation. J. Exp. Psychol. Hum. Percept.
36Baker, M.A. and Loeb, M. 1973. Implications of measurement of eye
fixations for a psychophysics of form perception. Perception &
37Mackworth, N. H. and Morandi, A.J. 1967. The gaze selects informative
details within pictures. Perception & Psychophysics 7:173–178.
38Boyatzis, C.J. and Varghese, R. 1994. Children’ emotional associations
with colors. Journal of Genetic Psychology 155(1):77-85.
39Lee, J.S. and Son, K.C. 1999. Effects of indoor plant and various colors
stimuli on the changes of brain activity and emotional responses. J.
Kor. Soc. Hort. Sci. 40:772-776.
40Hoshi, Y., Huang, J., Kohri, S., Iguchi, Y., Naya, M., Okamoto, T. and
Ono, S. 2011. Recognition of human emotions from cerebral blood
flow changes in the frontal region: A study with event-related near-
infrared spectroscopy. J. Neuroimaging 21(2):94-101.
41Davidson, R.J., Chapman, J.P., Chapman, L.P. and Henriques, J.B.
1990. Asymmetrical brain electrical activity discriminates between
psychometrically-matched verbal and spatial cognitive tasks.
42Phan, K.L., Wager, T., Taylor, S.F. and Liberzon, I. 2002. Functional
neuroanatomy of emotion: A meta-analysis of emotion activation
studies in PET and fMRI. Neuroimge 16:331–348.
43Reiman, E.M., Lane, R.D., Ahern, G.L., Schwartz, G.E., Davidson,
R.J., Friston, K.J., Yun, L.S. and Chen, K. 1997 Neuroanatomy
correlates of externally and internally generated human emotion. Am.
J. Psychiatry 154:918–925.
44Bondy, S.C., Lehman, R.A. and Purdy, J.L. 1974. Visual attention
affects brain blood flow. Nature 248:440-441.
45Kleiser, R., Wittsack, J., Niedeggen, M., Goebel, R. and Stoerig, P.
2001. Is V1 necessary for conscious vision in areas of relative cortical
blindness? Neuroimage 13:654–661.
46Rees, G. 2007. Neural correlates of the contents of visual awareness in
humans. Philosophical Transaction of the Royal Society of London B
47Ruggieri, V. 1999. The running horse stops: The hypothetical role of
the eyes in imagery of movement. Perceptual and Motor Skills
48Kaufman, A.J. and Lohr, V.I. 2004. Does plant color affect emotional
and physiological responses. Acta Hort. 639:229-233.
49Kuller, R., Mikellides, B. and Janssens, J. 2009. Color, arousal and
performance - a comparison of three experiments. Col. Res. Appl.
50Cutini, S., Basso Moro, S. and Bisconti, S. 2012. Functional near infrared
optical imagining in cognition neuroscience: An introductory review. J.
Near Infrared Spectrosc. 20:75-92.
51FitzGerald, M.T. 1996. Neuroanatomy: Basic and Clinical. W.B.
52Suzuki, M., Gyoba, J. and Sakuta, Y. 2005. Multichannel NIRS analysis
of brain activity during semantic differential rating of drawing stimuli
containing different effective polarities. Neurosci. Lett. 375(1):53–58.
53Kim, T.H., Song, J.K. and Jeong, G.W. 2012. Neural responses to the
human color preference for assessment of eco-friendliness: A functional
magnetic resonance imaging study. Int. J. Environ. Res. 6(4):953-960.