Numb to the world: Degradation desensitization and environmentally responsible behavior

Alexandra C. Alhadeff, MEM 20151


This study aims to explore the psychological effects of environmental degradation. The author proposes the concept of Degradation Desensitization (DD), which characterizes the loss of sensitivity to a previously aversive degradation stimulus, due to consistent exposure to that stimulus. The researcher predicts (i) that humans are averse to environmental degradation, and (ii) that consistent exposure to environmental degradation can lead to DD. Finally, the researcher hypothesizes that DD can lessen the likelihood that an individual will engage in environmentally responsible behaviors (ERBs).

A total of 147 middle and high school students were selected and randomly assigned to either a control or experimental group. In Parts I and III, 33 students participated in one-on-one and focus group semi-structured interviews. In Part II, over the course of four days, students in the experimental group were exposed to videos containing environmental degradation stimuli (EDS), while students in the control group watched videos that did not contain EDS. Students completed a survey before and after each viewing to assess their emotional and attitudinal changes and heart rate was monitored. Finally, students were given juice cartons following each viewing and their recycling behavior with respect to the empty cartons was observed. Results showed that students in the experimental group felt significantly more negative during and after the baseline video than students in the control. Further, younger participants felt more negative towards EDS than did older participants. Middle school students felt more negative with each subsequent video, but no similar effect was significant for high school students. Finally, on the third day, students in the experiment were significantly less likely to recycle than those in the control. Participants have a mental model of DD and were able to provide personal experiences, which align with the phenomenon, suggesting more legitimacy to the hypothesis.

It is hoped that this study will contribute to an understanding of the psychological effects of environmental degradation as well as the current literature on ERB.


On August 1 1955, a telling photograph was featured in Life magazine. The photograph depicted cans, frozen foods containers, disposable diapers, garbage bags, and a paper tablecloth falling from the sky like rain onto a smiling couple who were raising their arms towards the tumbling sea of trash. The caption underneath the photo read, “Throwaway living: disposable items cut down household chores.” The photograph reflected a paradigm shift away from the pre-World War II ‘waste not want not’ philosophy of living and toward a more wasteful zeitgeist.

A general rise in middle class income after World War II and the widespread availability of credit led to the age of consumerism and, consequently, the age of trash (Whiteley 1987). This increased consumption led to significantly higher levels of waste (Whiteley 1987). Waste is a critical form of environmental degradation that can be directly perceived by humans. This degradation raises the question: Why would individuals like the couple in the Life magazine photo smile in the face of something that should naturally cause aversion?

Some environmentalists and researchers assume that those who possess adequate knowledge of the environment will take adequate measures to protect it (Kollmuss & Agyeman 2002). Yet, this assumption is not fully supported by the wealth of literature on environmentally responsible behavior. Specifically, the current literature does not sufficiently explore how consistent exposure to environmental degradation can affect one’s attitudes towards the environment. Such exposure to environmental degradation may numb an individual’s concern for environmental problems in general, a response known as desensitization. Ultimately, desensitization may reduce an individual’s urge to engage in environmentally responsible behavior. The purpose of this study is to investigate whether exposure to environmental degradation leads to environmental desensitization and thus a decreased tendency to engage in environmentally responsible behavior.

Research question and objections

The purpose of this study was to examine biological, behavioral, and self-reported behavioral responses to environmental degradation. The guiding question in this research was: Does consistent exposure to environmental degradation lead to environmental desensitization and/or decreased likelihood of engaging in environmentally responsible behavior (ERB)? According to the Oxford English Dictionary, to degrade is “to lower in character or quality; to debase.” Thus, degradation of the environment involves the reduction of the quality of any aspect of the environment (e.g., air, water, soil). Quality implies a comparison between an original state and the status quo and consequently, for quality to change, there must be a change in state. By environmentally responsible behavior, the research refers to conscientious actions undertaken by individuals in order to mitigate negative impacts (by themselves, or others, or both) on the environment.

Specifically, the author addressed the following research questions:

  1. Are people averse to environmental degradation?

  2. Does consistent exposure of an individual to environmental degradation lead to degradation desensitization?

  3. Does degradation desensitization decrease the likelihood that an individual will engage in environmentally responsive behavior?


Research context

The study was conducted in the International School of Curitiba, Curitiba, Brazil (ISC, -25.368693, -49.327079), an independent private coeducational college preparatory school. The school enrolls roughly 500 students from pre-toddler (3 years old) through grade 12 (18 years old). ISC was selected because of its extensive representation of global cultures, including students from over 30 countries. Students at ISC are involved in several programs and activities where they learn to appreciate and protect the environment.

Curitiba is the capital city of the southern state of Parana, Brazil, and is a global model for urban development. Its successful recycling program “Lixo que nao é Lixo” (Garbage that is not Garbage) was commended by United Nations Environment Programme (Benton-Short & Short 2013, p.253). The city-wide environmental education initiative has been successful in involving 70% of the community residents, who now separate household organic and inorganic waste. Moreover, two-thirds of the city’s garbage is recycled (Rabinovitch 1992). Therefore, it can be assumed that the people of Curitiba are sensitive to, or at least aware of, the waste problem.


A group of students at ISC were invited to participate in the study (n = 147) via purposeful sampling. The sample was comprised of middle and high school students (11-17 years old). The students were primarily upper-middle to upper class. On a five-point scale, students were asked whether they had mostly lived in urban (1) or rural (5) environments, and the extent to which they generally engaged in ERB (1 = never, 5 = always), including recycling, water- and energy-saving measures.


Participants were randomly assigned to degradation (treatment) vs. non-degradation (control) experimental groups. Participants were informed that a study regarding waste perceptions would be conducted, but they were not aware of the desensitization aspect of the research. The study had three objectives: first to determine whether students showed aversion to waste imagery; second if consistent exposure to waste imagery led to desensitization to that imagery; and third whether desensitization affected their likelihood of engaging in ERB.


Data collection was performed in three distinct parts. In Part I, students were randomly assigned their treatment group, and one-on-one and focus group semi-structured interviews with fifteen students in each group were conducted. On day 1 of Part II, the experimental group completed a questionnaire regarding their background, current emotional state, and relationship with the natural world. Next, they were shown 5 minutes of video containing environmental degradation stimuli (EDS) from the film Trashed (2012), an award-winning documentary about waste, whereas the control group watched a 5-minute origami instructional video. Each participant’s heart rate was monitored before, during, and after exposure. After watching the video, participants were asked a series of questions regarding their current emotional state on a five-point scale (1 = negative, 5 = positive), as well as their relationship with the environment and how various scenes of the video made them feel. Students were given a complimentary juice carton, which had been marked with a number associated with each student. Students watched 15 minutes from the documentary on days 2, 3, and 4, during which the same measurements as on day 1 were taken. In Part III, the researcher conducted semi-structured interviews with the same students selected for interviews in Part I.



On day 1, participants were asked a series of questions about their background, including their sex, age, and the countries in which they had lived. On days 1, 2, 3, and 4, students were also asked questions related to their perceptions of trash and environmental degradation. Questions from the Environmental Identity Scale (Clayton 2003) were included to measure the students’ Nature Connectedness (NC), a proxy for environmental sensitivity. A total NC Score was calculated based on students’ responses. Students were also asked to rate their emotional state and perception of power on a five-point scale (1 = negative, 5 = positive) before and after each video.

Behavioral observation

During the interview, students were given a complimentary juice carton, which had been marked with a number associated with each student. Participants were observed as they disposed of the cartons. While classes were in session, the researcher inspected all recycling containers and collected the disposed cartons.


Students’ heart rate was monitored prior to exposure, during, and after using a heart rate monitor with chest strap (Pyle PHRM-22).


Semi-structured interviews were conducted with 33 students and were designed to assess environmental degradation perceptions of 11–17 year olds before and after the treatment. To ensure anonymity, students were identified using a random number during recording and transcripts. Initial interviews were 20–30 minutes in length and consisted of 15 questions to probe each student’s Nature Connectedness, cultural background, ERB, and perception of power. An additional 15 questions in the final interviews were designed to identify changes post-experiment. The interviews were either one-on-one or focus groups consisting of two or three students. A thematic analysis approach (Boyatzis 1998) was applied, and for each interview the transcript was coded on the basis of the selected themes. After reviewing the transcripts, the following themes emerged:

  1. Culture

  2. Environmentally responsible behavior

  3. Nature connectedness

  4. Environmental degradation

  5. Power

  6. Degradation desensitization

Several sub-themes were identified within each of these themes, and these were used to further assess the interview data.


Student background

A total of 147 students were invited to participate in the experiment, though not all students were present every day. On day 1, 114 students were present (62 male and 52 female). These students represented 36 countries, with over half having lived in two countries or more. Students’ ages ranged from 11 to 17 years (mean = 14 yrs, standard deviation = 0.7). On a scale from 1 (urban) to 5 (rural), students had spent most time in urban environments (M = 2.1, SD = 0.96).

Students were asked to rate the extent to which they engaged in ERB (1 = never, to 5 = always). Students reported that they often recycled (M = 3.8, SD = 0.9), and engaged in water-saving (M = 3.6, SD = 0.9) and energy-saving behaviors (M = 3.6, SD = 1.0). A moderate positive correlation was found between an individual’s nature connectedness score on day 1 and recycling (Pearson product-moment correlation, r = 0.30, n = 111, p = 0.002), water conservation (r = 0.40, n = 111, p < 0.001), and energy conservation behavior (r = 0.33, n = 111, p < 0.001).

Hypothesis 1: Are people averse to environmental degradation?

An independent-samples t-test was conducted to compare emotional change in participants who had been exposed to EDS during the first viewing (n = 47) and those who had not (n = 52). The emotional change variable was calculated by taking the difference between self-reported emotions before and during the video and before and after the video. There was a significant difference in the emotional change of the experimental (M = -1.55, SD = 1.25) and the control (M = -0.44, SD = 1.03) groups before the viewing and during the viewing (t97 = 4.834, p < 0.001). Additionally, there was a significant difference in the emotional change of the experimental (M = -1.06, SD = 1.15) and the control (M = -0.23, SD = 0.83) groups before and after the viewing (t97 = 4.380, p < 0.001). That is to say, there was a larger negative change in emotional state during and after exposure to EDS when compared to exposure to control imagery (Fig. 1).

Fig. 1. Mean emotional change prior vs. during EDS exposure and prior vs. after EDS exposure in experimental (E) and control (C) condition.

A paired-samples t-test was conducted to compare emotional state prior to exposure to EDS and emotional state during the baseline exposure (day 1). There was a significant difference between the self-reported emotional state prior (M = 3.95, SD = 0.87) and during (M = 2.55, SD = 0.899) exposure to EDS imagery in the experimental group (t54 = 8.47, p < 0.001). Emotional state became more negative during exposure to EDS. Further, there was a significant difference between the self-reported emotional state prior to (M = 3.95, SD = 0.870) and after exposure (M = 2.93, SD = 8.13; t54 = 7.35, p < 0.001). Self-reported emotional state prior to (M = 3.80, SD = 0.903) and during (M = 3.36, SD = 1.017) exposure differed significantly in the control group (t55 = 3.316, p = 0.002). Similarly, a significant difference was also found between self-reported emotional state prior to (M = 3.80, SD = 0.903) and after exposure to control stimuli (M = 3.55, SD = 0.952, t55 = 2.297, p = 0.025).

Younger students were more likely to be concerned about the environment. Student age was positively correlated with both trash-dependent emotions (Pearson correlation: r = 0.24, n = 114, p = 0.009) and environmental degradation-based emotions (r = 0.19, n = 114, p = 0.042), on a 1–5 scale (Fig. 2).

Fig. 2. Relationship between age and degradation-based emotion (left), and trash-based emotion (right) (1 = negative, 5 = positive). The size of each point is proportional to the number of students.

To further explore the effect of age, students’ self-report data were divided into two groups: middle (n = 69) and high school (n = 45). An independent samples t-test was conducted to compare trash-based emotions between middle (M = 1.67, SD = 0.76) and high school students (M = 1.98, SD = 0.69). Middle school students felt significantly more negative towards trash (t112 = -2.213, p = 0.029; Fig. 3).

Fig. 3. Difference in trash-based emotion between middle and high school students.

Further, students’ nature connectedness score (1–5) on day 1 was positively correlated with their perceived power to improve environmental problems (Pearson correlation, r = 0.41, n = 111, p < 0.001), as well as their feelings towards nature (r = 0.22, n = 111, p = 0.023), but showed a negative correlation with their feelings towards environmental degradation (r = -0.22, n = 111, p = 0.022).

Hypothesis 2: Does Degradation Desensitization exist?

Students’ ratings of emotion during the videos were analyzed using a mixed-design ANOVA with a within-subjects factor of exposure (day 1, day 2, day 3, day 4) and a between-subjects factor of group (control, experiment). Between subjects factors revealed a main effect of group (ANOVA, F1,70 = 49.99, p < 0.001), such that the mean emotion rating was more positive in the control than in the experiment. The predicted within-subjects effect of exposure was not significant (F3,210 = 0.64, p = 0.591). The interaction between exposure and group was also not significant (F3,210 = 1.16, p = 0.325; Fig. 5 left).

Similarly, students’ ratings of emotion after the videos were analyzed using a mixed-design ANOVA with a within-subjects factor of exposure (day 1, day 2, day 3, day 4) and a between-subjects factor of group (control, experiment). Between subjects factors revealed a main effect of group (F1,70 = 52.19, p < 0.001), such that the mean emotion rating was more positive in the control than in the experiment. The predicted within-subjects effect of exposure was not significant (F3,210 = 0.91, p = 0.437). The interaction between exposure and group was also not significant (F3,210 = 0.46, p = 0.711; Fig. 4 right).

Fig. 4. Student’s emotions during (left) and after (right) watching either the experiment (Trashed) or control (origami) videos. Results shown are for mixed ANOVAs with a within-subjects factor of exposure (day 1, day 2, day 3, day 4) and a between-subjects factor of group (control, experiment)

Two DD variables were calculated through the difference between trash-based and degradation-based emotions prior to the first treatment and after the final treatment. Though no significant difference was found between the control and experimental groups, when high school students and middle school students were taken separately, significant relationships were revealed. Middle school students (M = -0.33, SD = 0.83) in the experiment reported a significantly greater change in the negative direction environmental degradation post-treatment than middle school students in the control (M = 0.26, SD = 0.75; t59 = -2.945, p = 0.005; Fig. 5 left). While high school students showed no significant change, middle school students became more sensitive to environmental degradation after the treatment, which contradicts the alternate hypothesis that students would become less sensitive.

Further, though there was no significant difference in Nature Connectedness between middle and high school students in the treatment group on day 1, by day 4, middle school students (M = 31.19, SD = 4.45) reported a significantly higher NC score than high school students (M = 28.69, SD = 4.06, t55 = -2.197, p = 0.032).

Students’ heart-rate during the videos were analyzed using a mixed-design ANOVA with a within-subjects factor of exposure (day 1, day 2, day 3, day 4) and a between-subjects factor of group (control, experiment). The predicted within-subjects effect of exposure (F3,123 = 1.769, p = 0.16) and between-subjects effect of group (F1,41 = 2.81, p = 0.101), were not significant. The interaction between exposure and group was also not significant (F3,123 = 0.895, p = 0.45).

Behavioral observation: Hypothesis 3: DD lessens the likelihood that an individual will engage in ERB.

A chi-square test of independence was performed to examine whether individuals in the experimental group were less likely to recycle than those in the control. Though no significant relationship was found on the first day (X2(1, N = 142) = 0.037, p = 1.00), and second day (X2(1, N = 142) = 0.22, p = 0.694), we do see a trend towards significance on the third and fourth days. A significant relationship was revealed on day 3 (X2(1, N = 142) = 5.04, p = 0.030). Significance was not reached on day 4 (X2(1, N = 142) = 1.96, p = 0.186; Fig. 5 middle).


Sixty-four children (ages 11–17) participated in in-depth semi-structured one-on-one and focus group interviews regarding their perceptions of environmental degradation. The interviews were analyzed using grounded theory (Maxwell 2012) and identified power as being the overarching theme supporting the theory of DD, reinforced by cultural factors, and nature connectedness. More specifically, participants described a relationship between their assumed exposure to environmental degradation, perceived locus of control and how likely they were to engage in ERB. Participants also discussed how their cultural and familial upbringing informed their perceptions of the natural world.

Students were asked to rate on a five-point scale (1 = no power, and 5 = powerful) their locus of control (“Power to Change”) before and after the treatment. An independent-samples t-test was conducted to compare perceived locus of control between participants in the control group (n = 11) and the experiment (n = 21). There was a significant difference between perceived power before and after the treatment in the control (M = 0.546, SD = 0.282) and experimental (M = -0.429, SD = 1.363) conditions before the viewing and during the viewing (t30 = 2.116, p = 0.043; Fig. 5 right).

A single sample t-test was conducted to determine the degree of sensitivity of students in the experimental group (n = 21) to trash imagery. Students were asked to rate their sensitivity on the first and last videos on a five-point scale (1 = not sensitive, and 5 = very sensitive). Students were significantly more sensitive to the images in the first video (M = 2.90, SD = 1.04) compared to the images in the last video (M = 2.62, SD = 1.28; t20= 2.905, p < 0.001).

Fig. 5. Effect of degradation desensitiazation on student’s emotion and behavior. Mean degradation based emotion change pre- and post-four day treatment for middle school students (left). Proportion of students who recycled juice cartons after each treatment (middle; C = control, E = experiment). Change in power perception before and after treatment for control and experimental condition (right).


Hypothesis 1: People are averse to environmental degradation

The findings from this experiment are consistent with the hypothesis that exposure to environmental degradation imagery (EDS) may have a detrimental effect on emotion. Participants reported a significant change in emotion in the negative direction when exposed to EDS. When participants were asked to rate their emotions after the video, their emotional states did not return to pre-exposure levels, which was consistent with the original hypothesis. This finding suggests that EDS may induce negative emotions at the time of exposure and that these negative emotions are sustained.

An aversive response to environmental degradation is consistent with the aesthetic judgment component of the Biophilia Hypothesis (Kellert & Wilson 1995). “If through evolution, certain natural landscapes have promoted human survival and reproductive success, then … such landscapes nurture the human physiology and promote a sense of emotional well-being” (Kahn 1997). By extension, images of a degraded natural landscape may induce negative emotions. Harm to that landscape may be seen as harm to self. This experience can most aptly be described with the neologism solastalgia.

Solastalgia is “the distress that is produced by environmental change impacting on people while they are directly connected to their home environment” (Albrecht et al. 2007). A loss of ecosystem health can violate one’s sense of place and threaten well-being. Consistent with this theory, as predicted, the researcher found a significant relationship between a student’s connectedness to the natural world and her emotions stirred by environmental degradation. The higher the student scored in Nature Connectedness (NC), the more negative that student typically felt towards environmental degradation. It was clear through the interviews that students perceived the effects of environmental harm to transcend the environment itself and affect them personally. Some indicative quotes from student interviews include:

  1. It [environmental degradation] hurts us, it hurts the environment. We should make our planet so we can live a better life in it. (student #133)

  2. It affects us even indirectly. It is causing damage to us. (#122)

  3. We are killing ourselves by cutting down trees. Bebendo o proprio veneno [Drinking our own poison]. (#31)

  4. We do this to other people and to ourselves. (#34)

  5. They [people] are contributing to degradation and making their life worse. (#130)

  6. Earth doesn’t belong to us. We belong to the Earth. (#31)

All of the above students drew a connection between harm to the environment and harm to themselves. Though all the comments above demonstrate clear environmental concern, the reason behind the concern warrants further analysis.

Schultz (2001) outlines a tripartite classification of environmental concern: egoistic (care for self), altruistic (care for others), and biocentric (care for the biosphere). The form of environmental concern will depends on the individual’s interconnectedness with nature. The author proposes “objects (e.g., plants, animals, other people) are valued because of the degree to which they are included within an individual’s cognitive representation of self” (Schultz 2001). Those with higher perceptions of interconnectedness will display stronger biocentric concerns (Schultz 2001). Quotes 1 and 3 illustrate both egoistic concerns and biocentric concerns founded on the awareness of consequences for oneself or the communal or collective self, as signified by “us” or “ourselves” If the students are in fact referring to the communal “us,” this would indicate altruistic concern as well. Quote 4 clearly demonstrates both an egoistic and altruistic concern in that the student includes both others and himself in his construction, Quote 5, on the other hand, is altruistic only. Quote 6 appears to reflect only biocentric concern, with perhaps implicit egoistic and altruistic concerns insofar as what is good for the Earth would be good for everyone who belongs to the Earth.

Students’ concern for the environment, of whichever classification, was evident in the language they used to describe EDS. Students invariably used negative words such as bad, scared, sad, sickened, guilty, disgusted, and disappointed, to describe the EDS in the videos. Students 31 and 132 reported feeling physical pain or sickness in response to EDS:

You think you own the world. I feel like my heart is squeezing… I feel grief mixed with anger. (#31)

I feel sickened. It [environmental degradation] is like using drugs… you shouldn’t do something you know is going to be bad for you long-term. (#132)

The description of Student 31’s “heart squeezing” indicates an actual physical pain in addition to emotional pain, as stated by his “grief mixed with anger.” Student 132’s drug simile, in addition to associating environmental degradation with physical sickness, reflects the long-term temporal impact of environmental harm. This acknowledgment is especially notable given that, most people, when considering whether to engage in ERB, postpone the environmental penalty for the immediate gain of convenience. Collectively, the quotes make it clear that environmental degradation affects people on an emotional level and may negatively affect their well-being in the short- or long-term.

The effect of culture

Though the researcher contends that aversion to environmental degradation is universal, there is great variability in the individual, group, and cultural characteristics of the participants. The present study’s participants represent 36 countries, and over half have resided in at least two countries. Hence, these students have a unique and plural view of home as well as plural views of the environment. Understandably, their conceptions are not fixed, but malleable, shifting over geographical space and time. Many students could readily differentiate between environmental perceptions in the different places where they had lived. Below are several excerpts from interviews describing changes in ERB or environmental perception with the changing of home:

Student 81 was born in Curitiba but moved to France as a toddler where she lived for seven years. Student 81 then moved to Russia and back to France before returning to Curitiba in 2013. She stated:

Russia and France are very different. There was more pollution [in Russia], I can see it in the air: cars, factories [are causing the pollution]. I could smell and see the pollution. I never did that [recycling] in Russia. Mother stopped recycling in Russia. (#81)

Curitiba is better than in France. People put more effort into recycling and protecting the environment. I think it depends on the culture. (#81)

Though Student 81 did not know why her mother stopped recycling in Russia, she did acknowledge the power that culture has played on her conception of the environment. Indeed, consistent with the student’s observations, Moscow currently has no recycling program and the practice is considered “very un-Russian” (McGrane 2014).

Prior to Brazil, Student 99 had lived in Germany, Russia, Portugal, and Switzerland.

In Switzerland people were very fond of waste. You always had to recycle, glass, plastic, all the trash had to be recycled even clothes. I didn’t recycle in Portugal. Switzerland was where I learned to recycle. Switzerland was neater [than Brazil]. (#99)

Student 99’s use of the word “fond” to describe waste is interesting. Clearly, she did not mean that the Swiss people liked waste, but that they put great emphasis or consideration on waste. Accordingly, she elaborated that the Swiss people managed waste more appropriately than in her current home of Curitiba. The same student later associates the word “trash” with sadness. She feels like her Brazilian peers are not as involved in ERB as she is.

Student 136 was born in Japan to Brazilian parents of Japanese descent. He lived in Japan for eleven years before coming to Curitiba in 2012. Below, Student 136 reflects on how his cultural background has affected his environmental concern:

People care about waste in Japan … that can be because of ecologic policy2 in Japan. I would say why people in Japan care about it. Personally, I don’t care about the environment as Japanese do because I am in Brazil now and have Brazilian background. Even if I don’t care much, in Japan I had to follow the rules of the community. (#136)

Student 136 asserts that his concern for the environment is not dependent on one’s country of residence, but on one’s cultural heritage. On the other hand, the extent of his ERB is entirely dependent on the rules and regulations of his country of residence. For this reason, there is a disconnect between his belief and practice. His behavior is not dictated by ideology.

Hypothesis 2: Degradation Desensitization exists

The study demonstrated mixed results regarding the hypothesis that, to the extent DD exists, it is the loss of sensitivity to a previously aversive degradation stimulus due to consistent exposure to that stimulus. DD should not be confused with the concept of Nature Deficit (Louv 2006) and the more general ‘nature disconnect’. Degradation Desensitization is different from other published concepts of nature disconnectedness for the following reasons proposed by the author:

  1. Whereas “disconnect” theories explore how humans have become estranged to nature in general, DD explores the specific psychological effects of degradation.

  2. Whereas disconnect can be assumed to be a general consequence of a multitude of catalysts described in the literature (Louv, 2006), desensitization is what allows the ‘disconnect’ to progress. In other words, desensitization is not fixed, but fluid, increasing over time. One can fall into deeper and deeper states of disconnect via progressive desensitization. Therefore, degradation and degradation desensitization have a reinforcing relationship. As degradation increases, so does desensitization, which allows degradation to continue.

DD may be linked to the personal amnesia component of Shifting Baseline Syndrome. Shifting Baseline Syndrome is “a cautionary tale referring to changing human perceptions of biological systems due to loss of experience about past conditions” (Papworth et al. 2009). This phenomenon can occur at the generational level, where knowledge is lost because younger generations are not “aware of past biological conditions” and on the individual level, where people “forget their own experiences” (Papworth et al. 2009). Over time, there is an incremental decrease of environmental standards.

Because DD is a time-dependent phenomenon, it was predicted that younger individuals would be more sensitive to EDS than older individuals. This was supported by the modest positive correlation between both age and trash dependent emotions and environmental degradation emotions. Younger students were more averse to trash and environmental degradation than their older counterparts. In fact, middle school students in the experimental group became more sensitive to environmental degradation and trash over the course of the treatment, which contradicts Hypothesis 2. Because desensitization is progressive, older students may be less impressionable. Kaplan & Kaplan (2002) describe the adolescent “time-out,” where adolescents had a lower preference for natural settings, compared to younger children: “adolescents appreciate natural settings, though apparently not as much as do younger children or adults. They favor places where they can be with their peers and activities that convey excitement and action” (Kaplan & Kaplan 2002).

Students were asked to envision a landfill and to describe how their emotions and senses would be affected after one day, one week, one month, and one year. On the first day, 97% of students expressed negative emotions associated with being in the landfill. After one week, 18% of students felt more negative, 39% felt the same, and 43% felt less negative. After one month, 21% of students more negative, 24% of students felt the same, and 55% felt less negative. After the first year, 94% of students felt like they would feel less negative or entirely accustomed. Some notable examples include:

[After one year] I would be numbed by the sight of so much trash. I wouldn’t be annoyed anymore. (#104)

On the first month I would become used to it … after a year, I would become less human. (#35)

Aldo Leopold’s adaptation of Descartes’ famous dictum from “I think therefore I am” to “As a land-user thinketh, so is he” (Kellert & Wilson 1995) may provide some insight into Student 35’s comment. While Descartes proposes an anthropocentric view of the human identity, Leopold’s is biocentric. Both reflect that people’s thoughts do not exist in a vacuum. The human identity is as much about selfhood as it is about the natural world. It follows that our connection to the natural world is an important part of what makes us human. Student 35 points out that she would be less human once she lost her sensitivity to the degradation about her.

The evidence seems to show that people believe in DD. However, the literature on affective forecasting (Wilson & Gilbert 2005) argues that people may wrongly predict the type, direction, intensity, and duration of future emotions. Therefore, students may have underestimated the degree to which they would be emotionally affected by the landfill. The inverse situation may also be true where students overestimated the impact of the landfill and underestimated the degree to which they would become desensitized. Interestingly, “people fail to anticipate how quickly they will cope psychologically with such events in ways that speed their recovery from them.” (Wilson & Gilbert 2005). Because desensitization is a return to emotional neutrality post stimulus, this may be another reason why an individual may underestimate desensitization. Participants have a mental model of DD and were able to provide personal experiences, which align with the phenomenon, suggesting more legitimacy to the hypothesis.

Since I was little, my mother wanted to teach us the importance of recycling. She has this picture of a woman digging through a landfill … a big poster sized image. She kept that in her bedroom to remind us of how fortunate we were. As the years go on, we get less and less affected by the picture. (#56)

When I was a kid, the whole thing about animals getting caught in pieces of plastic really concerned me, but after a while it started to appear in every single animation, movie, documentary, and school, and by now, I’m not that concerned about it anymore. (#145)

Two students described similar stories where their aversion to air pollution in Curitiba lasted only a few months, because they became accustomed to it.

When I came here [Curitiba] from Japan, I think it [air pollution]really bad, but then I get used to it, so I don’t even feel it is bad anymore. I think [I got used to it in] a couple of months. (#136)

Air pollution. When I was in Canada, I was fine and didn’t have problems with asthma, but when I came back [to Curitiba], I have problems with asthma. It really annoys me because I don’t have as much conditioning. It smells different here. But you just learn to live with it. It took me half a year [to get used to it]. (#132)

Beyond their theoretical conception of DD, students also appeared affected by DD after watching videos depicting EDS over the course of several days. For example, the researcher found that participants felt significantly less sensitive to EDS on day 4 when compared to day 1.

That’s just what happens: after being exposed to information for too long, people adapt and get used to it. (#145)

You shut it out unconsciously because either you shut it out or you feel bad about yourself. (#132)

Our mind blocks out bad experiences so we don’t feel bad. Form of defense of the human mind. (#34)

It impresses me that humans stop getting impressed. It is human nature to get used to things. We must adapt. Keeping people continuously impressed is difficult because they’ll get used to it over time. (#116)

Based on their responses, the participants acknowledged DD both on a theoretical level and in their own apparent DD after watching videos depicting EDS.


The results confirmed that the DD participants experienced was very much a function of locus of control. Generally, students felt “overwhelmed” by the scope of environmental problems and did not believe they had the power to improve environmental problems. A common trend was the feeling that one’s power did not extend the boundary of one’s own personal actions or immediate community.

[Regarding power to improve environmental problems] Not global problems, but in your community of course. You can always try to clean up the trash, find out if it’s being taken care of problem. One person is not big enough to reach out to the world. Only if something extraordinary happens can someone affect the world. (#56)

We do have some power; if I have an idea I can spread it to family and other people and they can incorporate it in their lives. We have a small reach in our communities. (#143)

Further, students agreed that they had no power alone, but did have some power if they were part of a collective effort.

We have no power alone, but doing the work together we can help the environment. (#43)

They are just one person and there are so many other people; they see the trash even if you pick it up the next day it’s going to be there again.  It’s never going to get better and unless anybody else helps. (#99)

Yet, participants acknowledged that when an individual feels like the scope of a problem is beyond her grasp and thus its resolution, in her mind, impossible. Any action in the face of such an impossibility is then deemed worthless. This problem—this perceived impossibility—in essence, is ignored.

A lot of times, there are big problems elsewhere in other countries that everyone tends to ignore because they can’t do anything about it. Things that are too big that people can’t take care of are things people tend to ignore. Things that go on in the news or things that go on in our communities that we cant control. (#56)

It’s very complicated because these problems are so big. You are just one person, your actions are so small. You feel powerless; but if we don’t do it who is going to? It is part of your duty to take care of it. (#142)

Can’t do anything about it. Can take one thing [trash] out, but there is so much more. (#94)

The researcher found a strong positive correlation between NC and perception of power via the surveys. Students who scored higher on the NC scale were more likely to feel that they had the power to improve environmental problems. Accordingly, the less sensitive a student was to environmental problems, the less likely they were to feel they have the power to make a difference. Such students described becoming accustomed to things they felt they had no power to change.

After the initial frustration, we realize we’re useless. See it and get used to it. (#31)

At first I felt horrible. After some time I felt helpless and stopped paying attention. (#27)

If no one is recycling, no one wants to start because there are so many other people who don’t do it, especially when they feel like it won’t make a difference so they get used to it. They decide not to do something. They do not want to be the first person. (#99)

People say we can’t make a difference so we don’t get our hopes up. It is a noble dream, but no more than a dream. (#145)

Power affects my behavior. If I can make a difference, I will recycle. (#27)

Indeed, while students recognized the scope of the problem, some felt helpless while others felt empowered to at least address environmental problems on a personal level.

Hypothesis 3: Degradation Desensitization lessens the likelihood that an individual will engage in ERB.

We noticed a trend towards significance in the behavioral observation, with the experimental group recycling significantly less on the third day after watching three video clips of EDS. This indicates the existence of a lagged effect, in support of DD, whereby the effects of the IDS did not occur on the subsequent day only but over the course of several days. This is further supported by the significant positive relationship found between NC score and ERB, showing a direct connection between environmental sensitivity and ERB. Hence, an individual that becomes increasingly less sensitive may be increasingly less likely to engage in ERB.

Though Phillips (1983) notes that heavyweight prize matches, a form of media violence, triggered “a brief, sharp increase in US homicides,” there was a distinct lag in the effect, whereby peak violence was observed on the third day. One cannot presume the third day difference in the present study can be attributed to random variations because the difference was statistically significant. Interestingly, there was no longer a significant effect on the fourth day, which can be ascribed to random fluctuations. On the fourth day, students may have guessed that their behavior was being monitored and thus would have been more likely to recycle.

The decrease in recycling behavior is consistent with desensitization findings in the realm of violent media. Bushman & Anderson (2009) noted that participants who played a violent videogame took 450% longer to help a victim in a staged violent encounter, than those who had not played a violent videogame. Further, the moderate positive correlations found between NC and ERB indicate a relationship between environmental sensitivity and behavior. The researcher reasons that EDS, and perhaps more generally, exposure to environmental degradation, can affect one’s likelihood to engage in ERB. As discussed in the prior section, this may be the result of the individual’s perception of the scope of the problem and her locus of control.

There may be limitations with relation to the representativeness of the sample, which included 140 students from the International School of Curitiba. Thus, the sample may be disproportionately well educated. Future research should examine a larger and more diverse subset of the population.

Moreover, future studies may observe whether similar effects are seen when different forms of EDS are displayed. For example, one group could view a film about deforestation and another on fishery collapse. After all, people will have differing opinions regarding which forms of environmental degradation are most important, and the degree to which they respond to the imagery may be dependent on such perceptions. It would also be interesting to determine the effects of environmental degradation in different forms, for example, imagery only, without accompanying sound, or in live viewing of degradation rather than video depictions. Indeed, the researcher would predict that walking on a landfill would impact participants more than a video in a classroom removed from the environment.


In this study, the author proposes a new construct, Degradation Desensitization (DD), which is the loss of sensitivity to a previously aversive degradation stimulus due to consistent exposure to that stimulus. The overall objective of this research is to further the current literature on the psychological effects of environmental degradation as well as the impacts of these effects on behavior. It is appreciated that the hypotheses put forth in this paper should be regarded as highly speculative at the present time. The author hopes that a deeper understanding of DD may allow for the development of a new framework to promote environmentally responsible behavior.

What is the practical use of knowing how people perceive degradation, waste and/or the environment? As our world undergoes anthropogenic changes, it is critical to examine how these changes affect our well-being and our relationship with the natural world. Only by understanding this relationship can we hope to achieve behavioral change. The experience of environmental degradation can leave people feeling defeated and powerless. Ultimately, these feelings may trigger certain defense mechanisms, which may act as a hindrance to ERB. Our ability to understand these dilemmas will directly inform our capacity to construct appropriate environmental engagement and communication frameworks. If DD does exist, we cannot hope to change behavior without first implementing a re-sensitization effort. This may come in the form of a marketing effort that emphasizes how people can personally be affected by environmental degradation. Showing the positive effects of ERB may counteract the feelings of hopelessness reflected in participants’ responses regarding the scope of environmental degradation. In order to understand re-sensitization, a secondary study is needed. The research project should be interdisciplinary, conducted in cooperation with psychologists and conservationists.

Once again, the results illustrate a significant link between emotions and exposure to environmental degradation and support the validity of the Degradation Desensitization phenomenon. Accordingly, the findings of the present study may serve to further the discourse on environmental sensitivity and environmentally responsible behavior.


I would like to express my sincere gratitude to my advisor Professor Michael R. Dove, Professor Gregory R. Samanez-Larkin, Professor Susan Clayton, Professor Amity Doolittle, Professor Stephen R. Kellert and Samuel Johnson for their invaluable research guidance. This project would not have been possible without the support of Vanessa Benaci, Julia Wuestefeld, and the International School of Curitiba. Last but not least, I would like to extend a special thank you to Dr. Simon Queenborough for his insightful comments and the Tropical Resources Institute of the Yale School of Forestry & Environmental Studies for their generosity.


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  1. Alexandra Alhadeff is a second year MEM candidate at the Yale School of Forestry & Environmental Studies, especially interested in the intersection between psychology, economics, and conservation.

  2. The “ecologic policy” referenced by the student is the Law for the Promotion of Sorted Collection and Recycling of Containers and Packaging, which has been in place in Japan since 1997 in an effort to reduce waste (Japanese Ministry of the Environment).