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Parallels in Sources of Trauma, Pain, Distress, and Suffering in Humans and Nonhuman Animals


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It is widely accepted that animals often experience pain and distress as a result of their use in scientific experimentation. However, unlike human suffering, the wide range of acute, recurrent, and chronic stressors and trauma on animals is rarely evaluated. In order to better understand the cumulative effects of captivity and laboratory research conditions on animals, we explore parallels between human experiences of pain and psychological distress and those of animals based on shared brain structures and physiological mechanisms. We review anatomical, physiological, and behavioral similarities between humans and other animals regarding the potential for suffering. In addition, we examine associations between research conditions and indicators of pain and distress. We include 4 case studies of common animal research protocols in order to illustrate incidental and experimental factors that can lead to animal suffering. Finally, we identify parallels between established traumatic conditions for humans and existing laboratory conditions for animals.
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Journal of Trauma & Dissociation
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Parallels in Sources of Trauma, Pain,
Distress, and Suffering in Humans and
Nonhuman Animals
Hope Ferdowsian MDMPH
& Debra Merskin PhD
Physician's Committee for Responsible Medicine; Department of
Medicine, George Washington University, Washington, DC, USA
School of Journalism & Communication, University of Oregon,
Eugene, Oregon, USA
Available online: 24 Jan 2012
To cite this article: Hope Ferdowsian MDMPH & Debra Merskin PhD (2012): Parallels in Sources
of Trauma, Pain, Distress, and Suffering in Humans and Nonhuman Animals, Journal of Trauma &
Dissociation, 13:4, 448-468
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Journal of Trauma & Dissociation, 13:448–468, 2012
Copyright © Taylor & Francis Group, LLC
ISSN: 1529-9732 print/1529-9740 online
DOI: 10.1080/15299732.2011.652346
Parallels in Sources of Trauma, Pain,
Distress, and Suffering in Humans
and Nonhuman Animals
Physician’s Committee for Responsible Medicine; Department of Medicine, George
Washington University, Washington, DC, USA
School of Journalism & Communication, University of Oregon, Eugene, Oregon, USA
It is widely accepted that animals often experience pain and
distress as a result of their use in scientific experimentation.
However, unlike human suffering, the wide range of acute, recur-
rent, and chronic stressors and trauma on animals is rarely
evaluated. In order to better understand the cumulative effects
of captivity and laboratory research conditions on animals, we
explore parallels between human experiences of pain and psy-
chological distress and those of animals based on shared brain
structures and physiological mechanisms. We review anatomical,
physiological, and behavioral similarities between humans and
other animals regarding the potential for suffering. In addition,
we examine associations between resear ch conditions and indica-
tors of pain and distress. We include 4 case studies of common
animal resear ch protocols in order to illustrate incidental and
experimental factors that can lead to animal suffering. Finally,
we identify parallels between established traumatic conditions for
humans and existing laboratory conditions for animals.
KEYWORDS distress, ethics, posttraumatic stress, stress
It is widely acknowledged that nonhuman animals (hereafter, animals)
often experience pain and distress in the course of their use in scien-
tific experimentation (Gregory, 2004; Recognition, 2009). However, human
Received 11 August 2011; accepted 20 October 2011.
Address correspondence to Debra Merskin, PhD, School of Journalism & Communi-
cation, University of Oregon, Eugene, OR 97403. E-mail:
Downloaded by [University of Oregon] at 16:26 19 June 2012
Journal of Trauma & Dissociation, 13:448–468, 2012 449
interventions to minimize pain and distress in animals commonly focus on
reducing the numbers of animals used and making changes to specific pro-
tocols rather than evaluating the suffering individual animals experience
over the course of their lifetimes. This differs from the consideration of
human suffering, in which researchers examine the impact of acute, recur-
rent, and chronic trauma on individuals. Because animals are frequently used
in research, there is an ethical imperative to better understand the cumulative
effects of captivity and the rigors of laboratory research on animals.
In 1789, moral philosopher and legal scholar Jeremy Bentham noted
that it is the ability to suffer, not the ability to reason, that should be the
“insuperable line” (1789/1836, p. 236) that deter mines the treatment of other
beings, including infants, adults with particular disabilities, and animals.
According to Bentham,
A full-grown horse or dog is beyond comparison a more rational, as well
as a more conversable animal, than an infant of a day or a week or even
a month, old. But suppose the case were otherwise, what would it avail?
The question is not, Can they reason? Nor, Can they talk? But, can they
suffer? (p. 236)
Knowledge of pain, psychological distress, and suffering in humans and
other animals has evolved significantly since Bentham’s statement was first
published. Only in relatively recent history have scientists and physicians
acknowledged that human infants experience pain (Bellieni & Buonocore,
2010; Chamberlain, 1989). Furthermore, some have suggested that babies
and young children may experience more pain than adults because they
have not yet developed a mechanism that may reduce pain severity
(Dombrowski, 1997; Pluhar, 1993). As articulated by the International
Association for the Study of Pain (2007), “Pain is always subjective,” and
“the inability to communicate verbally does not negate the possibility that an
individual is experiencing pain” (Merskey & Bogduk, 1994, p. 211). Although
this statement was intended to apply to infants and other humans unable to
articulate their experiences, it can also be applied to nonhuman animals.
Suffering has been characterized in several ways. For example,
DeGrazia (2002) has posited that suffering occurs “when the source of pain is
unknown, when the meaning of the pain is dire, or when the pain is appar-
ently without end” (p. 35). Suffering has been defined as an unpleasant
subjective experience (Singer, 2006) or a “state of severe distress associ-
ated with events that threaten the intactness of the person” (Cassell, 2004,
p. 32). Although sometimes used synonymously with physical pain, suf fer-
ing can also originate and manifest psychologically. Perhaps more broadly,
suffering has been described by Morton and Hau (2002, p. 459) as “a nega-
tive emotional state which derives from adverse physical, physiological, and
psychological circumstances, in accordance with the cognitive capacity of
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450 H. Ferdowsian and D. Merskin
the species and the individual being, and its life’s experience.” Dawkins
(2008) has suggested that animal suffering can be measured empirically
through the evaluation of emotional states, as indicated by behavioral and
physiological parameters. Suffering can be defined as a set of negative emo-
tions such as fear and pain and recognized operationally as states caused
by negative reinforcers (Dawkins, 2008). Thus, suffering can manifest as
physical or mental experiences or both.
Here we address the following questions, drawing on Bentham
(1789/1836): In what ways do animals suffer physically and psychologically
as a result of their use in laboratory r esearch, and what are some of the gen-
eral factors that can lead to their suffering? In order to address our central
questions, we review anatomical, physiological, and behavioral similarities
between humans and other animals as they relate to the capacity for pain,
psychological distress, and suffering. We draw upon an evolutionary frame-
work that acknowledges convergence and divergence across species (Brüne,
2008; Cantor & Joyce, 2009; Marino, 2002; Stevens & Price, 2000). We also
explore evidence regarding the association between laboratory research con-
ditions, including captivity, and indicators of pain and psychological distress.
We identify parallels between established traumatic conditions for humans
and existing laboratory conditions for animals. Finally, we examine four case
studies of common animal research protocols in order to illustrate research
conditions that can lead to animal suffering.
Despite the obvious challenge posed by the fact that animals are generally
unable to report their physical and emotional states to humans, studies from
multiple disciplines provide objective evidence of animals’ abilities to expe-
rience pain. In fact, much of what experts understand about animal pain
stems from studies in which animals were intentionally exposed to painful
or distressful experiences.
Partially as a result of homologous anatomical structures and physio-
logical mechanisms, animals demonstrate coordinated responses to pain and
many emotional states and responses that are similar to those of humans.
As defined by the International Association for the Study of Pain (2007), pain
is “an unpleasant sensory and emotional experience associated with actual
or potential tissue damage, or described in terms of such damage” (p. 1979).
In its specific application to animals, Zimmermann (1986, p. 16) modified
the definition to include “an aversive sensory experience caused by actual or
potential injury that elicits progressive motor and vegetative reactions, results
in learned avoidance behavior, and may modify species-specific behavior,
including social behavior.”
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Journal of Trauma & Dissociation, 13:448–468, 2012 451
Anatomical and Physiological Similarities
In vertebrates, pain and proprioception are mediated by somatosensory
neurons of the trigeminal and dorsal root ganglia, which terminate in the
skin and other tissues. Somatosensory stimuli trigger electrical impulses that
are interpreted by the central nervous system (Lumpkin & Bautista, 2005).
Invertebrates have also demonstrated coordinated responses to painful stim-
uli. Cephalopods, such as octopuses, demonstrate well-organized nervous
systems that include brain centers concerned with sensory analysis, memory,
learning, and decision making (Hochner, Shomrat, & Fiorito, 2006; Mather,
2008). These areas of the cephalopod brain have been compared with the
cerebral cortex of vertebrates. As Mather (2008) has suggested, the conver-
gence of brain functions of invertebrate brains to those of vertebrates may
be even more relevant than anatomical comparisons.
Rather than taking a scala naturae or hierarchal approach, one can
explain similarities and differences in emotional processes across species
by the ways in which humans and animals have adapted to different eco-
logical niches (Shettleworth, 1998). Analgesics can modify pain responses
in animals as they do in humans. Pain may result in physiological changes
involving the heart, kidneys, immune system, and other organ systems that
are critical to disease progression and recovery (Gregory, 2004). Animals can
experience acute or immediate pain, as well as slow crescendo pain, such as
the pain of inflammation, visceral pain, and neuropathic pain. Although the
nociceptive pathways of pain are fairly well described, the molecular mech-
anisms involved in pain perception and the neurological responses to tissue
and neuronal injury are not well understood in humans or other animals.
This complicates the ability to adequately prevent, r ecognize, and treat pain
in animals. The pain and discomfort associated with disease (also called
sickness behavior) can be at least partially explained by shared cytokine-
mediated responses that can r esult in lethargy, depression, anorexia, sleep
disturbances, and enhanced sensitivity to pain (Dantzer & Kelley, 2007).
Cytokines have sickness-inducing properties, partly as a result of the acti-
vation of the hypothalamic–pituitary–adrenal (HPA) axis. Sickness behavior
occurs in mammals and birds (Dantzer & Kelley, 2007), and it is now under-
stood that communication systems that link the immune and central nervous
systems, although nonspecific, are biologically critical for survival and recov-
ery. However, the sickness response can become maladaptive, resulting in a
variety of chronic inflammatory diseases and depression.
Pain may be experienced differently depending on genetic and environ-
mental differences. Genotype may affect susceptibility to heat or other forms
of pain, and sensitivity to pain and pain-related traits may in part be heri-
table (Lariviere & Mogil, 2010). Factors such as sleep deprivation have also
been associated with pain perception, although the direction of causality is
sometimes unclear (Lautenbacher, Kundermann, & Krieg, 2006). In addition
to individual differences, other physical and psychological stressors can
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452 H. Ferdowsian and D. Merskin
contribute significantly to the perception of pain as well as to an individual’s
ability to cope with pain.
Behavioral Similarities
Animals express pain in ways similar to humans, including through
avoidance behaviors, abnormal postures, guarding to protect an affected
area, vocalizations such as whimpering, aggression, and physiological and
endocrine responses, among others (Gregory, 2004). Furthermore, the antic-
ipation of pain can result in mood and behavioral changes that exacerbate
psychological distress (Ploghaus et al., 1999).
Behavioral observations have been important in ascertaining when
and how animals experience pain. However, just as there are variations
in the expression of suffering within human populations, there are also
differences across species and between individual animals. Because of evo-
lutionary pressures, some animals may be more likely than others to use
certain response behaviors. For example, many animals develop mecha-
nisms that suppress signs of acute and chronic pain, particularly during times
of extreme fear (Gregory, 2004; McGowan, Stubbs, & Goff, 2007). Animals
vulnerable to predation may attempt to hide signs of pain in attempts to
enhance survival (Moberg & Mench, 2000) but may experience psychological
sequelae. Animals often exhibit fearful, avoidant, and hypervigilant behav-
iors considered parallel to those expressed by traumatized humans (Cohen,
Matar, Richter-Levin, & Zohar, 2006).
The brain demonstrates significant plasticity. Although form and function
are guided by genetic factors, environment and experiences help shape
brain structure, function, and activity. In anxiety and depressive disorders,
the combination of stressors overwhelms normal physiological responses,
sometimes causing structural and physiological changes. The structures and
neuroendocrine mechanisms associated with these conditions are shared
across a wide range of animals.
Fear, anxiety, and relevant reactions and responses serve as an organ-
ism’s first line of defense (Kim & Gorman, 2005; Lang, Davis, & Ohman,
2000). Some of these responses are dependent upon the activation of a
common subcortical circuit (Lang et al., 2000; Panksepp, 2004). As a result,
reactions associated with fear occur much more quickly than do slower,
language-based appraisals (Lang et al., 2000). The absence of certain neu-
rological structures may also be relevant to suffering because animals with
less organized neural circuits may demonstrate less flexibility and have more
limited coping mechanisms. Some animals may suffer more than humans
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Journal of Trauma & Dissociation, 13:448–468, 2012 453
would in an analogous situation because of their inability to understand
what is happening to them, make sense of their plight, escape from it, or
alter their conditions.
Mammals share a large number of brain regions associated with emo-
tional affect, including the amygdala, hippocampus, hypothalamus, and
prefrontal cortex, among other areas (Broom, 2010; Murray, 2007; Panksepp,
1982, 1998, 2004; Rolls, 2005). As a result, there are homologies in attach-
ment disorders, depression, complex anxiety disorders, and persistent
disorders of social behavior (Brüne, 2008). For example, fear r esponses are
stored as memories and linked to the amygdala and can be expressed in
mammals as anxiety disorders and specific phobias (Brüne, Brüne-Cohrs,
McGrew, & Preuschoft, 2006; Kim & Gorman, 2005). The hippocampus,
found in all vertebrates, is involved in memory storage and retrieval and may
explain some of the similarities in chronic psychopathology across species.
In humans and other animals, chronic posttraumatic stress has been asso-
ciated with decreased hippocampal volumes (Gregory, 2004) and changes
to other areas of the brain, including the prefrontal cortex (Gregory, 2004;
Otani, 2004), perhaps because of recurrently and chronically elevated lev-
els of cortisol, followed by downregulation of the HPA axis (Cohen et al.,
2006; Gregory, 2004). Abnormalities of the HPA axis have been identified
in animals who have been confined, restrained, or isolated and after sur-
gical procedures (Gregory, 2004). Moreover, studies have indicated that
hypothalamic nerve growth factor levels are responsive to and modified by
psychological stimuli, most likely associated with anxiety and fear (Alleva
& Francia, 2009). Similar anatomical changes have also been noted across
species. For example, captivity of only a few weeks duration can reduce the
volume of the hippocampus of birds by as much as 23% (Tarr, Rabinowitz,
Imtiaz, & DeVoogd, 2009), potentially resulting in memory deficits.
Variations of posttraumatic stress disorder have been described in chim-
panzees and other animals (Bradshaw, Capaldo, Lindner, & Grow, 2008;
Brüne et al., 2006; Ferdowsian et al., 2011). Mice show persistent fear and
increases in sensitized fear related to hyperarousal, emotional blunting, and
social withdrawal, as seen in posttraumatic stress disorder (Siegmund &
Wotjak, 2006). A study of juvenile rats designed to model childhood trauma
found that exposing the rats to litter soaked in predator (cat) urine increased
the likelihood that they would develop long-term behavioral disruptions
thought to represent posttraumatic stress symptom equivalents. When the
rats were exposed a second time in adulthood, the responses persisted
(Cohen et al., 2006).
Researchers have also described signs of depression in animals, includ-
ing nonhuman primates, dogs, pigs, cats, birds, and rodents, among others.
For example, learned helplessness and other characteristics of depres-
sion, such as anhedonia, have been described in mice and other animals
(Strekalova, Spanagel, Bartsch, Henn, & Gass, 2004). Mice also demonstrate
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454 H. Ferdowsian and D. Merskin
empathic responses when painful stimuli are inflicted on individuals they
know (Langford et al., 2006).
Pain and distress are commonly experienced in the laboratory as a result
of experimental protocols or incidentally (Balcombe, Barnard, & Sandusky,
2004; Carbone, 2004; Newcomer, 2000; Panksepp, 2004). Potential sources
of pain and distress are present from birth (or even the prenatal period) to
death and can include birth conditions, maternal separation, confinement,
cage transfers, handling, painful procedures, social isolation, restraint, and
deprivation of simple needs (e.g., adequate sleep, food, water, and shel-
ter). For use in research, animals are regularly transported from a breeding
facility or natural habitat to a laboratory. Animals also experience social
deprivation, the inability to fulfill natural behaviors (e.g., hygienic practices,
natural movement), lack of natural habitat, conditions of over- or understim-
ulation, and witnessing of harming and killing of peers. Many of these factors
resemble potentially traumatic conditions and consequences of human cap-
tivity that have been described elsewhere (Brenner, 2010). Here we explore
parallels between traumatic conditions for humans and common laboratory
conditions for animals and explore the similar pathologies resulting from
these conditions. Table 1 also illustrates cross-species parallels regarding the
potential for physical and psychological trauma.
Severed Bonds and Social Deprivation
Animals of many species rely upon early parental support for their devel-
opment. Animals also commonly form bonds with conspecifics for adequate
TABLE 1 Common Potential Sources of Trauma in Humans and Other Animals
Physical trauma Psychological trauma
Deprivation of basic needs, including
water, food, sunlight, and sleep
Social deprivation and neglect or social
Withholding of adequate nutrition Isolation or inability to seek solitude
Inadequate provision of shelter, sanitation,
and hygiene
Sensory deprivation or overstimulation
Restriction of physical activity or exercise Deprivation of the ability to fulfill
natural behaviors or loss of autonomy
Invasive procedures, including sharp and
blunt trauma, burns, induced diseases,
unnecessary surgical procedures, and
forms of death
Threats to physical integrity or threats
of death
Withholding of adequate health care Witnessing of painful or distressful
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Journal of Trauma & Dissociation, 13:448–468, 2012 455
social support and development. Among both humans and animals, if a par-
ent is not present early in life, offspring are likely to develop stereotypic
behaviors (Bowlby, 1969, 1973, 1980; Latham & Mason, 2008). Maternally
deprived animals develop a suite of changes in neurotransmitter activity and
anxiety and stress responses, including increases in stereotypic behaviors
(Gregory, 2004; Latham & Mason, 2008; Lutz, Well, & Novak, 2003; Mason,
Although developmental periods vary widely by species, deprivation-
induced stereotypic behaviors are fairly typical. It is common for laboratory
animals to be separated from their mothers earlier than would be the case
if they were “free living” (Latham & Mason, 2008). Interruption in maternal
care, or restricted access to mothers who are sometimes less able to care
for their young because they themselves were also maternally deprived, cre-
ates distress in animals that can extend beyond infancy and adolescence.
For example, laboratory mice are typically separated from their mothers
at 20 days (Würbel & Stauffacher, 1997), whereas free-living rodents are
weaned around 35 days (Latham & Mason, 2004). Bar biting and other abnor-
mal behaviors have been described in mice used in laboratory research as
a response to premature weaning, thwarted attempts to suckle, or unpleas-
ant cage experiences (Callard, Bursten, & Price, 1999; Waiblinger & Konig,
2004; Würbel & Stauffacher, 1997). Among mouse pups, precocious wean-
ing contributes to anxiety and aggression (Kikusui, Isaka, & Mori, 2005).
Kittens who are removed too early from their mothers often display anxi-
ety and exhibit wool-sucking behaviors (Bowen & Heath, 2005). Premature
separation from mothers also leads to a range of adverse behavioral and
social effects in primate infants (Dettling, Feldon, & Pryce, 2002; Harlow,
Dodsworth, & Harlow, 1965; Novak, Meyer, Lutz, & Tiefenbacher, 2006;
C. M. Rogers & Davenport, 1969). Stereotypic and self-directed behaviors
have been described in peer-reared rhesus macaques and chimpanzees, par-
ticularly those who spent their first few months in incubators (Bloomsmith,
Baker, Ross, & Pazol, 2002; Champoux, Metz, & Suomi, 1991; Erwin, 1986;
Lutz et al., 2003).
Prolonged Isolation and Sensory Deprivation
Among humans, solitary confinement is associated with increased risk for
psychopathology, including symptoms of depression and anxiety (Andersen
et al., 2000; Brenner, 2010). Even in conditions in which they choose to be in
a temporarily isolating environment, such as polar expeditions, individuals
frequently experience depression, anxiety, paranoia, and physical symptoms
such as headaches and impaired cognition (Suedfeld & Steel, 2000).
Animals who are purposefully bred for research or captured from the
wild are routinely confined to cages prior to and during experimental pro-
tocols. Cats, dogs, rodents, nonhuman primates, and other animals are
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456 H. Ferdowsian and D. Merskin
inherently social but are frequently kept under conditions of prolonged iso-
lation and sensory deprivation. As a result, animals can exhibit abnormal
behaviors such as whole-body stereotypies and self-mutilation, which can
be traced to maternal deprivation, confinement, sensory deprivation, isola-
tion, and other laboratory experiences (Avgustinovich & Kovalenko, 2005;
Brüne et al., 2006; Latham & Mason, 2008; Lutz et al., 2003). Standard lab-
oratory housing also appears to cause changes in nonhuman primates’ and
rodents’ brain regions (Kozorovitskiy et al., 2005) important to memory, such
as the hippocampus.
Isolation and lack of social stimulation can contribute to distress, par-
ticularly among animals whose natural behaviors are highly social and
involve seeking and play (Smith & Taylor, 1996). For example, tail biting,
stereotypies, and neurotic behaviors are often exhibited in pigs without
access to stimulation (Rollin & Kesel, 1995). Littermate-deprived kittens have
demonstrated prolonged separation effects and failed to develop social com-
munication skills (Guyot, Bennett, & Cross, 1980; Guyot, Cross, & Bennett,
1980). Dogs who are isolated and deprived of sensory stimulation also
exhibit a variety of behavioral pathologies ranging from crying to domi-
nance aggression (Gregory, 2004; Panksepp, Herman, Conner, Bishop, &
Scott, 1978). Other manifestations in dogs, such as fear, generalized anxi-
ety, obsessive-compulsive disorder, predatory aggression, noise phobia, and
impulse control, often appear in the first few years of life when neural
systems are maturing (Overall, 1994, 2005; Overall & Dunham, 2002).
Sensory Overstimulation, Sleep Deprivation, and Circadian Cycle
Exposure to florescent light and disruption of sleep cycles are typical tools
in the interrogation of humans (Cusick, 2006; Saar & Novak, 2005). Sounds
are used for similar purposes and can result in symptoms such as ear pain,
anxiety, disorientation, and disrupted cognition (Brenner, 2010, p. 473).
Similarly, environmental factors such as light, human interaction, cage
cleaning, sound, and transport can all influence well-being in animals
(Castelhano-Carlos & Baumans, 2009). Laboratory conditions can be noisy,
bright, and confusing to animals (Rollin & Kesel, 1995). Noises common
in human environments can be frightening to animals because of their
lack of familiarity and animals’ greater sensitivity to sound (Clough, 1982).
Ventilation systems, movement of equipment, human voices, vocalizations of
other animals, and the operation of equipment all contribute to the stressors
of the laboratory environment (Faith & Hessler, 2006). The effects of sound
on human and animal neuroendocrine, cardiovascular, and sleep functions
have been well documented. Loud noises can impair cardiovascular func-
tion, HPA axis regulation, hippocampal and memory encoding activity, and
amygdala activity (Brenner, 2010; Day, Nebel, Sasse, & Campeau, 2005;
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Journal of Trauma & Dissociation, 13:448–468, 2012 457
Gregory, 2004). Sleep deprivation among humans and animals has been
found to increase the risk for impaired immunological, cardiovascular, and
cognitive performance (Caldwell & Redeker, 2005; Kales et al., 1984; N. L.
Rogers, Szuba, Staab, Evans, & Dinges, 2001). For example, sleep depriva-
tion has been found to cause hyperarousal in mice (Lopez-Rodriguez, Kim,
& Poland, 2004) and aggressive behavior, weight loss, and adverse changes
in physiological parameters in rats (Rechtschaffen & Bergmann, 2002; Webb,
1962). Sleep deprived mice and rabbits have demonstrated impairments in
immune function (Toth, 1995).
Threats to Physical Integrity and Life
Among human political prisoners and detainees, threats of death, mock exe-
cutions, exposure to extremes in temperature, confinement to overly small
spaces, and injuries are common torture techniques that induce significant
fear and anxiety (Brenner, 2010). Techniques such as water boarding can
result in feelings of helplessness and fear of death. Likewise, intentionally
exposing animals to predator threats (Cohen et al., 2006), placing them in
positions in which they will be subjected to aggressive behaviors by con-
specifics (Van der Meer, Van Loo, & Baumans, 2004), provoking aggression,
or repeating procedures that have caused physical or psychological distress
in the past can cause animals to exhibit evidence of anticipatory anxiety
(Pfaff, 2002). In fact, foundational experiments that led to theories of learned
helplessness and clinical depression involved conditioning dogs and mice
with inescapable electric shocks (Seligman, 1972; Seligman & Maier, 1967).
Similar findings have been described in other animals.
We reviewed common animal research protocols to identify research condi-
tions that can contribute to pain, distress, and suffering. The cases reviewed
include the forced swim test commonly conducted with mice, spinal cord
injury experiments in cats, cardiac pacing studies in dogs, and toxicity
studies using monkeys. General details of these protocols are provided
here. Furthermore, we explore some of the experimental and incidental
harms associated with each research protocol, building upon the foundation
provided previously.
Mice: Forced Swim Test
A common research protocol that uses mice is the forced swim test (see
Figure 1). Although many of the primary symptoms of depression, such
as low self-esteem, guilt, and suicidal ideation, are difficult or impossible
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458 H. Ferdowsian and D. Merskin
FIGURE 1 Forced swim test.
to elicit from animals (Castagné, Moser, & Porsolt, 2009), the forced swim
test is commonly used in preclinical antidepressant efficacy screening
protocols (Petit-Demouliere, Chenu, & Bourin, 2004). This experimental
protocol is designed to demonstrate symptoms of depression, including
learned helplessness, in rodents. In the forced swim test (also known as the
behavioral despair test), mice are placed in containers of water of which
they cannot touch the bottom or from which they cannot escape. The time
rodents spend swimming, struggling, and floating is measured. Some mice
struggle throughout the entire scheduled session, whereas others eventually
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Journal of Trauma & Dissociation, 13:448–468, 2012 459
become passive and float, moving only enough to keep their eyes and
noses above water. Resignation (behavioral despair, learned helplessness) is
used as a primary behavioral parameter for antidepressant activity (Porsolt,
Brossard, Hautbois, & Roux, 2001). Periods of immobility are measured in
relationship to pharmaceutical intervention.
As a result of the forced swim test, researchers have reported profound
chronic changes in biological and behavioral parameters in rodents (Becker
et al., 2008). Behavioral despair, induced hyperactivity of the HPA axis, loss
of body weight, and hypothermia often occur after the stress of the proto-
col. The prolonged immobility of the forced swim test amplifies feelings of
Cats: Spinalization
Cats are used in spinal cord injury experiments, in which they are anes-
thetized and intubated while a laminectomy is performed (Marcoux &
Rossignol, 2000). The cats’ spinal cords are then severed with surgical scis-
sors and an absorbable hemostat is placed to fill the space, followed by
suturing of the wound. The wounds remain partially open to reveal the
spinal cord, and S-hooks are attached through which pressure is admin-
istered to approximate weight-bearing loads. The cats awaken paralyzed.
After surgical intervention, the cats are placed in individual cages, with
daily interventions including manual bladder expression and cleaning of
their hindquarters.
Dogs: Ventricular Pacing
Dogs are used in ventricular pacing studies, in which their heart rates
are elevated for extended periods of time to approximate heart failure in
humans. Although the normal heart rate for adult dogs is 70–120 beats per
minute, cardiac pacing protocols dictate rapid pacing from 130 to more than
600 beats per minute (Ahlberg, Ripplinger, Skadsberg, Iaizzo, & Mulligan,
2007; Everett et al., 2000; Khoury et al., 2009). Tachycardia is maintained, in
some cases for days and weeks at a time. Protocols include surgical inter-
vention, instrumentation, rapid atrial or ventricular pacing, pharmacological
intervention, and euthanasia. Cardiovascular consequences include severe
ventricular arrhythmias, changes in hemodynamic parameters (e.g., blood
pressure and vascular resistance), physiological changes (e.g., heart rate, car-
diac output, stroke volume, contractility and relaxation), and death (Ahlberg
et al., 2007; Everett et al., 2000; Khoury et al., 2009).
Monkeys: Toxicology Tests
Monkeys are commonly used in toxicity tests in order to estimate the poten-
tial effects in and risks to humans (Dorato & Buckley, 2006; Gad, 2009;
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460 H. Ferdowsian and D. Merskin
Grote-Wessels, Frings, Smith, & Weinbauer, 2009; Korte, Vogel, & Osterburg,
1987). A typical method for studying acute systemic toxicity among primates
is “a pyramiding dosage design” (Gad, 2009, p. 215). Drugs are administered
in escalating amounts via oral, intravenous, and pulmonary routes, including
gavage. Monkeys are exposed to the highest tolerable levels (Hayes, 2007,
p. 1608), although death, particularly in reproductive and developmental
toxicology studies, is not unusual (Buse, Habermann, Osterburg, Korte, &
Weinbauer, 2003; Martin & Weinbauer, 2010).
Monkey fetuses and infants are used to investigate drug effects on
organogenesis; toxic doses are typically administered to the mothers during
pregnancy or lactation. Mothers are captured from the wild or purposefully
bred, shipped, caged, and repeatedly handled in the laboratory. Their
offspring often abort or die early. If infants survive, they are typically taken
from their mothers shortly after birth. In one protocol, colony-bred adult
female rhesus monkeys were purchased from China for use in Japan, where
the monkeys were kept in stainless steel cages (Yasuda et al., 2005). Male
monkeys were housed with female monkeys on Days 12, 13, and 14 of the
female monkeys’ menstrual cycles in order to induce sexual intercourse and
pregnancy. Pregnancy was confirmed with ultrasound after monkeys were
anesthetized with ketamine. Subsequently, pregnant mothers were weighed
every 20 days and injected with varying dosage levels of dioxin. Once the
babies were delivered, they lived with their mothers for 1 year and were
exposed to dioxin through breast milk. The young monkeys were weighed
every 10 days, then euthanized, so researchers could examine morbidity
and mortality associated with dioxin exposure. Morbidity included severe
dental disease.
The examples presented here highlight research conditions that can con-
tribute to pain, distress, and suffering. In addition to the pain and distress
associated with experimental protocols, animals also experience pain,
distress, and suffering as a result of routine aspects of the laboratory
environment. Thwarted opportunities to fulfill and express species-specific
behaviors can also result in suffering (Jensen & Toates, 1993; Rollin, 2010).
All of the cases described here include the potential for experimental
and incidental har ms, such as severed bonds and social deprivation, isola-
tion and sensory deprivation, the inability to fulfill natural behaviors, and
threats to animals’ physical integrity and lives. For example, mice used in
forced swim test protocols experience near-drowning and hypothermia as
well as sleep disruption and depression (which are goals of the experimen-
tal intervention), shipment, frequent handling and cage transfers, instrument
placement, and confinement.
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Journal of Trauma & Dissociation, 13:448–468, 2012 461
Likewise, spinal cord injury experiments expose cats to many of the
incidental harms incurred by mice in addition to life-threatening complica-
tions of spinal cord injury, including infection and shock. Cats are placed in
single-cage housing and prevented from fulfilling natural behaviors, lack
solitude and privacy, and are incapable of performing normal hygienic
Dogs also experience pain, distress, and suffering as a result of their use
in heart failure experiments. Like cats and mice, dogs are prevented from
forming normal bonds and engaging in normal socialization. Dogs experi-
ence threats to their physical integrity and lives (rapid ventricular pacing
and heart failure), overstimulation, disruption of natural sleep cycles, and
an inability to control or stop the pain and discomfort associated with the
Monkeys also experience experimental and incidental harms as a result
of their use in toxicology experiments. Experimental harms include severe
pain and repeated threats to their physical integrity and lives. Incidental
harms include conditions of capture and breeding, maternal separation and
deprivation, isolation, and transport, among others. These monkeys and their
offspring are also unable to fulfill natural behaviors such as socialization and
Anatomical, physiological, and behavioral similarities across species demon-
strate that animals experience pain and distress in ways similar or identical to
humans. There are also commonalities in the factors that contribute to pain,
distress, and suf fering in humans and other animals. Furthermore, animals’
vulnerability and dependence on humans while in captivity likely contribute
to their suffering.
Although researchers can never be certain of the details of the expe-
riences of other animals, or even other humans, animals have necessary
and sufficient structures, systems, and mechanisms from which pain, dis-
tress, and suffering can occur. We have not exhausted the list of potential
harms to animals as a result of their use in laboratory research. Rather, our
goal was to consider and illustrate shared conditions of suffering among
humans and other animals. It is also worth noting that, just as human sur-
vivors react and recover in a range of ways, depending on their severity of
exposure, developmental level, support systems, coping mechanisms, and
recovery environment, so may animals in certain circumstances. Not all indi-
viduals experience long-term physical or psychological sequelae of trauma.
Nevertheless, it is the potential for physical and psychological trauma that
inevitably contributes to the ethical considerations regarding the use of ani-
mals in research. These findings also have implications regarding other ways
in which animals are used by humans.
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Luxembourg: Office for Official Publications of the European Communities.
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... Moreover, although "all NHPs are housed with visual and auditory contact with conspecifics" ( [91], p. 4), and thus not necessarily in groups, this is certainly not enough to satisfy their complex social needs. Furthermore, depending on the experimental procedures and on the legal requirements of the countries in which NHPs are housed (see below), NHPs may also experience suffering from early maternal separation [92][93][94][95]. In Europe, for instance, macaques are usually weaned around 8 months [91], a developmental stage in which infants are still largely dependent on their mothers under natural conditions [96], whereas transgenic monkeys are usually separated from their mothers from birth (see [91]) with a strong negative impact on their behaviour and physiology [97]. ...
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Invasive research on primates (i.e., laboratory research that implies body manipulations causing pain or distress that is not aimed to directly improve the individuals’ well-being) has a long history. Although some invasive studies have allowed answering research questions that we could not have addressed with other methods (or at least not as quickly), the use of primates in invasive research also raises ethical concerns. In this review, we will discuss (i) recent advances in the study of primates that show evidence of complex behaviour and cognition, (ii) welfare issues that might arise when using primates in invasive research, (iii) the main ethical issues that have been raised about invasive research on primates, (iv) the legal protection that primates are granted in several countries, with a special focus on the principle of the 3Rs, and (v) previous and current attempts to ban the use of primates in invasive research. Based on this analysis, we suggest that the importance of a research question cannot justify the costs of invasive research on primates, and that non-invasive methods should be considered the only possible approach in the study of primates.
... Using these two principal criteria, Sneddon et al. (2014) show that animals in many taxa, including mammals, birds, amphibians and reptiles, fish, and arthropods, do physically feel pain. These findings are corroborated by Ferdowsian and Merskin (2012), who conclude that there are anatomical (major organs and tissues like liver, heart, and muscles), physiological (cortisol and beta-endorphin levels) and behavioural (seeking social companionship) similarities that are identical to how animals and humans experience pain. ...
Research on animal ethics continues to escalate in tourism but does so in the absence of a comprehensive statement on animal suffering. This paper aims to rectify this deficiency through two broad aims. The first is to define suffering and related terms and provide a brief statement on the science of suffering; highlight issues related to the ethics of animal suffering; and provide a brief discussion on policy and suffering. The second aim is to develop a roadmap to eliminate animal suffering in tourism as a priority. The theoretical framework adopted in this paper rests within care ethics and empathy.
... This minimum level of care does not protect an animal's interest in not suffering nor acknowledge any interest in honoring them if they appear to withhold consent for procedures or anything else done to them (Durham & Merskin, 2009). Animals suffer significantly not only physically but also psychologically when experimented upon, housed, and transported (Ferdowsian & Merskin, 2012). 3. Lyme disease is a bacterial infection from an infected black-legged tick (Lyme disease, 2019). ...
... , social sciences (Bastian, Costello, & Loughnan, 2011;Merskin, 2018;Ferdowsian & Merskin, 2012), and sciences (Bekoff, 2006), as well as philosophers (Regan, 2010) have asked over the centuries. ...
... Only recently, a study on wild living chimpanzees revealed the significance of maternal care on the survival of infant chimpanzees even beyond nutritional dependence 39 . Several studies demonstrated that atypical rearing conditions and traumatic experiences during this time period produce long-lasting negative effects in chimpanzees [40][41][42] , affecting among others, their social skills 43 , their personality profile 44 and their cortisol levels at an adult age 45 . Bradshaw et al. 46 and Ferdowsian et al. 47 supposed that traumatic early life experiences in chimpanzees cause symptoms which they defined as Complex Post-Traumatic Stress Disorder (PTSD), and these symptoms are comparable to those of human trauma survivors who suffered highly distressing events at an early age. ...
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Advances in the field of social network analysis facilitate the creation of multiplex networks where several interaction types can be analysed simultaneously. In order to test the potential benefits of this approach, we investigated the sociability of atypically raised chimpanzees by constructing and analysing 4-layered multiplex networks of two groups of former pet and entertainment chimpanzees (Pan troglodytes). These networks are based on four social interaction types (stationary vicinity, affiliative behaviour, allogrooming, passive close proximity) representing low- to high-level interaction types in terms of sociability. Using the tools provided by the MuxViz software, we could assess and compare the similarity and information gain of each these social interaction types. We found some social interaction types to be more similar than other ones. However, each social interaction type imparted different information. We also tested for a possible impact of the chimpanzees’ biographical background on the social interaction types and found affiliative behaviour as well as allogrooming to be affected by adverse early life experiences. We conclude that this multiplex approach provides a more realistic framework giving detailed insight into the sociability of these chimpanzees and can function as a tool to support captive care management decisions.
This article is an exploration of Psychological Operations, focusing on both the role which fear plays in Psychological Operations, and how the Russian Federation employed Psychological Operations in the War in Ukraine (2014–2021). A qualitative methodology is used to explore fear as a neurological, psychological and social phenomenon, and how it may be utilised in Psychological Operations. The author finds that Russia’s initial use of Psychological Operations was focused on making tactical gains against the Ukrainian military. Shock tactics, combined with strategic messaging, encouraged mass defections from the Ukrainian army and border guard, significantly degrading the combat effectiveness of Kyiv’s forces, and increasing the likelihood of victory for the Donbass secessionists. The case study is limited in scope to 2014–2021. The paper can thus be read as both an analysis of one element of Russia’s shaping phase prior to the 2022 invasion, and/or a framework for analysing the current stage of conflict.
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Contract Research Organizations (CROs) conducting toxicology studies on behalf of biopharmaceutical sponsors and others routinely provide supportive care for animals to minimize pain and distress on studies. A large number of guidance documents govern the care of experimental animals, however there is currently no uniform approach on the communication between sponsor and their CRO partners in providing a standard definition of and strategies for administering supportive care in toxicity studies. This survey was conducted by the CRO Outreach Working Group (WG), a part of the 3Rs Translational and Predictive Sciences (TPS) Leadership Group of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ Consortium), to better understand the provision of supportive care on nonclinical studies. The survey aimed to define supportive care strategies, identify alternatives to supportive care, and understand regulatory feedback and implications about supportive care decisions. The survey was distributed to members of the 3Rs Leadership Group of the IQ Consortium and several CRO partners, representing 35 organizations as potential respondents. The results of the survey from 13 respondents provided positive feedback that helped in highlighting the existing best practices for supportive care. Areas of enhancements identified included greater consistency in the inclusion of sponsor veterinarians on project teams for externalized studies, the timing of initiation of supportive care, and increased sharing of regulatory outcomes. Suggested best practices include creating a plan of action for veterinary care prior to study start, and enhancing information sharing regarding expected toxicities from previous study findings. Improved communication regarding supportive care will pave the way for enhanced 3Rs initiatives, refining the existing animal care paradigm and helping to ensure the most ethical toxicology study designs.
Within the field of human research, respect for bodily liberty and integrity (summarily, bodily sovereignty) has arguably driven the creation and enforcement of relevant rules and regulations. These concepts are reflected in documents such as the Belmont Report, which emphasizes respect for autonomy and specific protections for individuals with compromised autonomous decision-making capacities. However, little to no attention is given to respect for the bodily sovereignty of nonhuman animals in research or other areas of society, despite its importance in determining health and well-being.
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Human and animal research both operate within established standards. In the United States, criticism of the human research environment and recorded abuses of human research subjects served as the impetus for the establishment of the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research, and the resulting Belmont Report. The Belmont Report established key ethical principles to which human research should adhere: respect for autonomy, obligations to beneficence and justice, and special protections for vulnerable individuals and populations. While current guidelines appropriately aim to protect the individual interests of human participants in research, no similar, comprehensive, and principled effort has addressed the use of (nonhuman) animals in research. Although published policies regarding animal research provide relevant regulatory guidance, the lack of a fundamental effort to explore the ethical issues and principles that should guide decisions about the potential use of animals in research has led to unclear and disparate policies. Here, we explore how the ethical principles outlined in the Belmont Report could be applied consistently to animals. We describe how concepts such as respect for autonomy and obligations to beneficence and justice could be applied to animals, as well as how animals are entitled to special protections as a result of their vulnerability.
Animal Physiotherapy is an essential reference guide for physiotherapists looking to apply the proven benefits of physiotherapy to the treatment of companion and performance animals. Animal Physiotherapy is a growing profession of physiotherapists who have broadened their expertise from the well-established human sphere to animals. The positive perception of physiotherapy in the human sphere, together with an increased awareness of options and expertise available for animals has resulted in a strong demand for physiotherapy for animals. For the physiotherapist this book provides essential applied background information on animal behaviour, nutrition, biomechanics and exercise physiology. For veterinarians and others who work with animals, the book reviews the scientific principles behind the practice of physiotherapy, and what it can achieve. Includes reviews of different physiotherapy techniques, drawing on both human and animal literature; Discusses approaches in small animal medicine as well as for elite equine athletes; Includes applied evidence-based clinical reasoning model, providing case examples.
This is a revised and expanded edition of a classic in palliative medicine, originally published in 1991, with three added chapters and a new preface summarizing our progress in the area of pain management. The obligation of physicians to relieve human suffering stretches back into antiquity. But what exactly, is suffering? One patient with cancer of the stomach, from which he knew he would shortly die, said he was not suffering. Another, someone who had been operated on for a minor problem-in little pain and not seemingly distressed-said that even coming into the hospital had been a source of pain and suffering. With such varied responses to the problem of suffering, inevitable questions arise. Is it the doctor's responsibility to treat the disease or the patient? And what is the relationship between suffering and the goals of medicine? According to the author of this book, these are crucial questions, but ones that have unfortunately remained only queries void of adequate solutions. It is time for the sick person, the author believes, to be not merely an important concern for physicians but the central focus of medicine. With this in mind, he argues for an understanding of what changes should be made in order to successfully treat the sick while alleviating suffering, and how to actually go about making these changes with the methods and training techniques firmly rooted in the doctor's relationship with the patient. © 1991, 2004 by Oxford University Press, Inc. All rights reserved.
In countries of origin, nonhuman primates compete for space with rapidly expanding human populations. The loss of primary habitat as a result of the encroachment of humans on previously undeveloped areas is clearly the most serious threat to wild primates. As primate ranges become restricted, competition within species (as well as between species) intensifies. At critical levels, populations exceed carrying capacities by so much that they cannot be sustained, and rapid declines in numbers result. It is necessary that optimal sizes for wild preserves be identified if conservation in natural settings is to achieve long-term success.
The book links the analysis of the brain mechanisms of emotion and motivation to the wider context of what emotions are, what their functions are, how emotions evolved, and the larger issue of why emotional and motivational feelings and consciousness might arise in a system organized like the brain. The topics in motivation covered are hunger, thirst, sexual behaviour, brain-stimulation reward, and addiction. The book proposes a theory of what emotions are, and an evolutionary, Darwinian, theory of the adaptive value of emotion, and then describes the brain mechanisms of emotion. The book examines how cognitive states can influence emotions, and in turn, how emotions can influence cognitive states. The book also examines emotion and decision-making, with links to the burgeoning field of neuroeconomics. The book describes the brain mechanisms that underlie both emotion and motivation in a scientific form that can be used by both students and scientists in the fields of neuroscience, psychology, cognitive neuroscience, biology, physiology, psychiatry, and medicine.
Among the cardinal principles of both toxicology and pharmacology is that the means by which an agent comes in contact with or enters the body does much to determine the nature and magnitude of an effect. However, a rigorous understanding of formulations, routes, and their implications to the design and analysis of safety studies is not widespread. And in the day-to-day operations of performing studies in animals, such an understanding of routes, their manipulation, means and pitfalls in achieving them, and the art and science of vehicles and formulations is essential to the sound and efficient conduct of a study. In this chapter we show that there are at least 26 potential routes of administration, of which 10 are commonly used in safety assessment.
This compact, easy-access guide to behavioral problems encountered in veterinary practice offers immediate and helpful advice for today's veterinary team. Instructor resources are available please contact your Elsevier sales representative for details. Coverage offers immediate advice to the veterinary team who are often presented with behavioral problems in their practice. Easy-to-read format includes introductions, medical differentials, underlying causes, diagnosis, action boxes, and summaries. Content refers the reader to other chapters throughout the book, so that information can be found quickly and easily. Helpful handouts, which can be photocopied, offer yet another way to further your learning experience.