Islamic psychology or Ilm-al Nafsiat refers to the study of the Nafs (meaning "self" or "psyche" in Arabic) in the Islamic world, particularly during the Islamic Golden Age (8th–15th centuries) as well as modern times (20th–21st centuries), and is related to psychology, psychiatry and the neurosciences.
Some of the advances in medieval Islamic psychological thought included the establishment of the first mental hospitals, the development of a clinical approach to mental illness, and the development of an experimental approach to the study of the mind. In the 20th and 21st centuries, attempts to revive psychological concepts from medieval Islamic thought have been attempted by modern Muslim psychologists and Islamic scholars.
In medieval Islamic medicine in particular, the study of "mental illness was a speciality of its own", and was variously known as "diseases of the mind," al-‘ilaj al-nafs (approximately "curing/treatment of the ideas/soul/vegetative mind," also translated more simply as "psychotherapy"), al-tibb al-ruhani ("the healing of the spirit," or "spiritual health") and tibb al-qalb ("healing of the heart/self," or "mental medicine").
This Quranic verse summarized Islam's attitudes towards the mentally ill, who were considered unfit to manage property but must be treated humanely and be kept under care by a guardian, according to Islamic law. This positive neuroethical understanding of mental health consequently led to the establishment of the first mental hospitals in the medieval Islamic world from the 8th century, and an early scientific understanding of neuroscience and psychology by medieval Muslim physicians and psychological thinkers, who discovered that mental disorders are caused by dysfunctions in the brain.
In the philosophy of mind, certain hadiths indicate that dreams consist of three parts, and early Muslim scholars also recognized three different kinds of dreams: false dreams, patho-genetic dreams, and true dreams.
One of the earliest Muslim psychological thinkers was Abu Bakr Muhammad Ibn Sirin (654–728), who was renowned for his Ta’bir al-Ru’ya and Muntakhab al-Kalam fi Tabir al-Ahlam, a book on dreams. The work is divided into 25 sections on dream interpretation, from the etiquette of interpreting dreams to the interpretation of reciting certain Surahs of the Qur'an in one's dream. He writes that it is important for a layperson to seek assistance from a an Alim (Muslim scholar) who could guide in the interpretation of dreams with a proper understanding of the cultural context and other such causes and interpretations. Al-Kindi (Alkindus) (801–873) also wrote a treatise on dream interpretation entitled On Sleep and Dreams.
In consciousness studies, al-Farabi (Alpharabius) (872-951) wrote the On the Cause of Dreams, which appeared as chapter 24 of his Book of Opinions of the people of the Ideal City, was a treatise on dreams, in which he was the first to distinguish between dream interpretation and the nature and causes of dreams.
Avicenna (Ibn Sina) (980-1037), while he was imprisoned in the castle of Fardajan near Hamadhan, wrote his famous "Floating Man" thought experiment to demonstrate human self-awareness and self-consciousness and the substantiality of the soul. He referred to the living human intelligence, particularly the active intellect, which he believed to be the hypostasis by which God communicates truth to the human mind and imparts order and intelligibility to nature. His "Floating Man" thought experiment tells its readers to imagine themselves suspended in the air, isolated from all sensations, which includes no sensory contact with even their own bodies. He argues that, in this scenario, one would still have self-consciousness. He thus concludes that the idea of the self is not logically dependent on any physical thing, and that the soul should not be seen in relative terms, but as a primary given, a substance. Avicenna also wrote about the potential intellect (within man) and active intellect (outside man) and that cognition cannot be produced mechanically but involves intuition at every stage. As an analogy, he compares the ordinary human mind to a mirror upon which a succession of ideas reflects from the active intellect. He writes that a mirror can be rusty at first (i.e. before acquiring knowledge from the active intellect), but when the mirror is polished (i.e. when one thinks), the mirror can then readily reflect light from the Sun (i.e. the active intellect).
H. Chad Hillier writes the following on the contributions made by Averroes (Ibn Rushd) (1126-1198) to the field of psychology:
One of Avicenna's most influential theories in psychology and epistemology is his theory of knowledge, in which he developed the concept of tabula rasa, a precursor to the nature versus nurture debate in modern psychology. He argued that the "human intellect at birth is rather like a tabula rasa, a pure potentiality that is actualized through education and comes to know" and that knowledge is attained through "empirical familiarity with objects in this world from which one abstracts universal concepts" which are developed through a "syllogistic method of reasoning; observations lead to propositional statements, which when compounded, lead to further abstract concepts." He further argued that the intellect itself "possesses levels of development from the material intellect (al-‘aql al-hayulani), that potentiality that can acquire knowledge to the active intellect (al-‘aql al-fa‘il), the state of the human intellect at conjunction with the perfect source of knowledge.
In the 12th century, the Andalusian-Arabian philosopher and novelist Ibn Tufail (known as "Abubacer" or "Ebn Tophail" in the West) first demonstrated Avicenna's theory of tabula rasa as a thought experiment in his Arabic novel, Hayy ibn Yaqzan, in which he depicted the development of the mind of a feral child "from a tabula rasa to that of an adult, in complete isolation from society" on a desert island. The Latin translation of his work, entitled Philosophus Autodidactus, published by Edward Pococke the Younger in 1671, had an influence on John Locke's formulation of tabula rasa in An Essay Concerning Human Understanding, which went on to become one of the principal sources of empiricism in modern Western philosophy, and influenced many Enlightenment philosophers, such as David Hume and George Berkeley.
Avicenna was the first to divide human perception into five external senses (the classical senses of hearing, sight, smell, taste and touch known since antiquity) and five internal senses which he discovered himself: the sensus communis (seat of all senses) which integrates sense data into percepts; the imaginative faculty which conserves the perceptual images; the sense of imagination which acts upon these images by combining and separating them, serving as the seat of the practical intellect; Wahm (instinct) which perceives qualities (such as good and bad, love and hate, etc.) and forms the basis of a person's character whether or not influenced by reason; and intentions (ma'ni) which conserve all these notions in memory.
Al-Ghazali (Algazel) (1058-1111) stated that the self has motor and sensory motives for fulfilling its bodily needs. He wrote that the motor motives comprise of propensities and impulses, and further divided the propensities into two types: appetite and anger. He wrote that appetite urges hunger, thirst, and sexual craving, while anger takes the form of rage, indignation and revenge. He further wrote that impulse resides in the muscles, nerves, and tissues, and moves the organs to "fulfill the propensities."
Al-Ghazali was also one of the first to divide the sensory motives (apprehension) into five external senses (the classical senses of hearing, sight, smell, taste and touch) and five internal senses, which he was able to describe more accurately than Avicenna. The five internal senses discovered by al-Ghazali were: common sense (Hiss Mushtarik) which synthesizes sensuous impressions carried to the brain while giving meaning to them; imagination (Takhayyul) which enables someone to retain mental images from experience; reflection (Tafakkur) which brings together relevant thoughts and associates or dissociates them as it considers fit but has no power to create anything new which is not already present in the mind; recollection (Tadhakkur) which remembers the outer form of objects in memory and recollects the meaning; and the memory (Hafiza) where impressions received through the senses are stored. He wrote that, while the external senses occur through specific organs, the internal senses are located in different regions of the brain, and discovered that the memory is located in the hinder lobe, imagination is located in the frontal lobe, and reflection is located in the middle folds of the brain. He stated that these inner senses allow people to predict future situations based on what they learn from past experiences.
In The Revival of Religious Sciences, al-Ghazali also writes that the five internal senses are found in both humans and animals. In Mizan al Amal, however, he later states that animals "do not possess a well-developed reflective power" and argues that animals mostly think in terms of "pictorial ideas in a simple way and are incapable of complex association and dissociation of abstract ideas involved in reflection." He writes that "the self carries two additional qualities, which distinguishes man from animals enabling man to attain spiritual perfection", which are 'Aql (intellect) and Irada (will). He argues that the intellect is "the fundamental rational faculty, which enables man to generalize and form concepts and gain knowledge." He also argues that human will and animal will are both different. He writes that human will is "conditioned by the intellect" while animal will is "conditioned by anger and appetite" and that "all these powers control and regulate the body." He further writes that the Qalb (heart) "controls and rules over them" and that it has six powers: appetite, anger, impulse, apprehension, intellect, and will. He states that humans have all six of these traits, while animals only have three (appetite, anger, and impulse). This was in contrast to other ancient and medieval thinkers such as Aristotle, Avicenna, Roger Bacon and Thomas Aquinas who all believed that animals cannot become angry.
In the Encyclopedia of the Brethren of Purity (10th century), the Brethren of Purity discussed the soul, brain, and process of thought. They divided the soul into three parts: the vegetative, animal and rational human souls. The vegetative soul is concerned with nutrition, growth and reproduction; the animal soul is concerned with movement, sensation, perception and emotion; and the rational human soul is concerned with thinking and talking. Contrary to the Aristotelian view of the heart being the most important organ, the Brethren of Purity considered the brain as the most important organ of the body, due to it being responsible for higher functions such as perception and thought.
The Arab Muslim physician An-Naysaburi (d. 1016) wrote the Kitab al-Uquala al-Majanin, in which he used the term Mahwus for patients with delusions and hallucinations. He attempted to explain the phenomenon of madness and insanity in philosophical terms, rather than the psychopathological methods used by his contemporaries. He considered life as a blending of opposites such as health and disease, and wrote that reason is mixed with madness so that even the sane are never free from madness.
Ibn Miskawayh (941–1030) wrote the books Tahdhib al-Akhlaq (Cultivation of Morals) and Al-Fauz al-Asgar (The Lesser Victory), in which he gives psychological advice on certain issues, such as the fear of death, the need to develop traits to restrain oneself from faults, and the concept of morality. He also introduced the concepts of "self reinforcement" and response cost, where he advises Muslims who feel guilt to learn to punish themselves physically or psychologically through charity, fasting, etc.
Al-Ghazali (Algazel) (1058-1111) discussed the concept of the self and the causes of its misery and happiness. He described the self using four terms: Qalb (heart), Ruh (spirit), Nafs (soul) and 'Aql (intellect). He stated that "the self has an inherent yearning for an ideal, which it strives to realize and it is endowed with qualities to help realize it." He also stated that there are two types of diseases: physical and spiritual. He considered the latter to be more dangerous, resulting from "ignorance and deviation from God", and listed the spiritual diseases as: self-centeredness; addiction to wealth, fame and social status; and ignorance, cowardice, cruelty, lust, waswas (doubt), malevolence, calumny, envy, deception, and greed. To overcome these spiritual weaknesses, al-Ghazali suggested the therapy of opposites ("use of imagination in pursuing the opposite"), such as ignorance & learning, or hate & love. He described the personality as an "integration of spiritual and bodily forces" and believed that "closeness to God is equivalent to normality whereas distance from God leads to abnormality."
Ibn Bajjah (Avempace) (d. 1138) "based his psychological studies on physics." In his essay, Recognition of the Active Intelligence, he wrote that active intelligence is the most important ability of human beings, and he wrote many other essays on sensations and imaginations. He concluded that "knowledge cannot be acquired by senses alone but by Active Intelligence, which is the governing intelligence of nature." He begins his discussion of the soul with the definition that "bodies are composed of matter and form and intelligence is the most important part of man—sound knowledge is obtained through intelligence, which alone enables one to attain prosperity and build character." He viewed the unity of the rational soul as the principle of the individual identity, and that by its contact with the Active Intelligence, it "becomes one of those lights that gives glory to God." His definition of freedom is "that when one can think and act rationally". He also writes that "the aim of life should be to seek spiritual knowledge and make contact with Active Intelligence and thus with the Divine."
Ibn al-Nafis (1213-1288) dealt with psychology in his Commentary on Anatomy in Avicenna's Canon. He developed his own theories on hylomorphic psychology and philosophy, mostly on a theological basis. In particular, he made a distinction between the soul and the spirit, and he developed his own theory on the soul. He also crtiticized the ideas of Avicenna and Aristotle on the soul originating from the heart. Ibn al-Nafis rejected this idea and instead argued that the soul "is related to the entirety and not to one or a few organs." He further criticized Aristotle's idea that every unique soul requires the existence of a unique source, in this case the heart. Ibn al-Nafis concluded that "the soul is related primarily neither to the spirit nor to any organ, but rather to the entire matter whose temperament is prepared to receive that soul" and he defined the soul as nothing other than "what a human indicates by saying ‘I’.
Ali ibn Sahl Rabban al-Tabari's Firdous al-Hikmah written in the 9th century was the first work to study 'al-‘ilaj al-nafs (translated as "psychotherapy" from Arabic) in the treatment of patients. His ideas were primarily influenced by early Islamic thought and ancient Indian physicians such as Sushruta and Charaka. Unlike earlier physicians, however, al-Tabari emphasized strong ties between psychology and medicine, and the need for al-‘ilaj al-nafs and counseling in the therapeutic treatment of patients. He wrote that patients frequently feel sick due to delusions or imagination, and that these can be treated through "wise counselling" by smart and witty physicians who could win the rapport and confidence of their patients, leading to a positive therapeutic outcome. In his chapter on mental illness, al-Tabari first described thirteen types of mental disorders, including madness, delirium, and Fasad Al-Khayal Wal-Aqo ("damage to the imagination, intelligence and thought"). He also clearly highlighted mental illness as a speciality of its own.
The Tunisian Arab Muslim physician, Ishaq ibn Imran (d. 908), known as "Isaac" in the West, wrote an essay entitled Maqala fil-L-Malikhuliya, in which he first described psychosis, and also described a type of melancholia: the "cerebral type" or "phrenitis". He described the diagnosis of this mental disorder, reporting its varied symptoms. The main clinical features he identified were sudden movement, foolish acts, fear, delusions, and hallucinations of black people. This work was later translated into Latin as De Oblivione (On Forgetfulness) by Constantine the African.
The Persian physician Muhammad ibn Zakarīya Rāzi (Rhazes) (865-925) wrote the landmark texts El-Mansuri and Al-Hawi in the 10th century, which presented definitions, symptoms, and treatments for many illnesses related to mental health and mental illness. Razi's texts made significant advances in psychiatry. Razi also managed the mental ward of a Baghdad hospital. Such institutions could not exist in Europe at the time, because of European fears of demonic possession.
In the centuries to come, Islam would serve as a critical waystation of knowledge for Renaissance Europe, through the Latin translations of many scientific Islamic texts. Razi, al-Tabari and Ahmed ibn Sahl al-Balkhi were the first known physicians to study al-‘ilaj al-nafs.
Ali ibn Abbas al-Majusi (d. 982) discussed mental illness in his medical text, Kitab al-Malaki, where he discovered and observed a type of melancholia: clinical lycanthropy, associated with certain personality disorders. He wrote the following on this particular mental illness:
Avicenna (980-1037) often used psychological methods to treat his patients. One such example involved a prince of Persia who had melancholia and suffered from the delusion that he was a cow. He would low like a cow, crying "Kill me so that a good stew may be made of my flesh," and would not eat anything. Avicenna was persuaded to undertake the case, and sent a message to the patient, asking him to be happy, as the butcher was coming to slaughter him, and the sick man rejoiced. When Avicenna approached the prince with a knife in his hand, he asked, "Where is the cow so I may kill it." The patient then lowed like a cow to indicate where he was. By order of Avicenna in his role as the butcher, the patient was also laid on the ground for slaughter. When Avicenna approached the patient, pretending to slaughter him, he said, "The cow is too lean and not ready to be killed. He must be fed properly and I will kill it when it becomes healthy and fat." The patient was then offered food, which he ate eagerly and gradually "gained strength, got rid of his delusion, and was completely cured.
According to the psychologist Amber Haque, the medieval Islamic scholar Abu Zayd Ahmed ibn Sahl al-Balkhi (850-934) was "probably the first cognitive and medical psychologist to clearly differentiate between neuroses and psychoses, to classify neurotic disorders, and to show in detail how rational and spiritual cognitive therapies can be used to treat each one of his classified disorders."
Al-Balkhi classified neuroses into four emotional disorders: fear and anxiety, anger and aggression, sadness and depression, and obsession. According to Haque, al-Balkhi further classified three types of depression: normal sadness (huzn) which is "today known as normal depression", "endogenous depression" which "originated within the body", and "reactive depression" which "originated outside the body".
Al-Balkhi also wrote that a healthy individual should always keep healthy thoughts and feelings in his mind in the case of unexpected emotional outbursts in the same way drugs and First Aid medicine are kept nearby for unexpected physical emergencies. He stated that a balance between the mind and body is required for good health and that an imbalance between the two can cause sickness. Al-Balkhi also introduced the concept of reciprocal inhibition (al-ilaj bi al-did), which was re-introduced over a thousand years later by Joseph Wolpe in 1969.
In the early 10th century, Muhammad ibn Zakarīya Rāzi reported a psychotherapeutic case study from a contemporary Muslim physician who treated a woman suffering from severe cramps in her joints which made her unable to rise. The physician cured her by lifting her skirt, putting her to shame. He wrote: "A flush of heat was produced within her which dissolved the rheumatic humour."
Ali ibn Abbas al-Majusi (d. 982) elaborated on how the physiological and psychological aspects of a patient can have an effect on one another in his Complete Book of the Medical Art. He found a correlation between patients who were physically and mentally healthy and those who were physically and mentally unhealthy, and concluded that "joy and contentment can bring a better living status to many who would otherwise be sick and miserable due to unnecessary sadness, fear, worry and anxiety." He also first discussed various mental disorders, including sleeping sickness, memory loss, hypochondriasis, coma, hot and cold meningitis, vertigo epilepsy, love sickness, and hemiplegia. He also placed more emphasis on preserving health through diet and natural healing than he did on medication or drugs, which he considered a last resort.
Avicenna (980-1037) recognized "physiological psychology" in the treatment of "illnesses involving emotions" and develop "a system for associating changes in the pulse rate with inner feelings" which is seen as an anticipation of "the word association test of Jung." Avicenna identified love sickness (Ishq) when he was treating a very ill patient by "feeling the patient's pulse and reciting aloud to him the names of provinces, districts, towns, streets, and people." He noticed how the patient's pulse increased when certain names were mentioned, from which Avicenna deduced that the patient was in love with a girl whose home Avicenna was "able to locate by the digital examination." Avicenna advised the patient to marry the girl he is in love with, and the patient soon recovered from his illness after his marriage.
Avicenna also gave psychological explanations for certain somatic illnesses, and he always linked the physical and psychological illnesses together. He described melancholia (depression) as a type of mood disorder in which the person may become suspicious and develop certain types of phobias. He stated that anger heralded the transition of melancholia to mania, and explained that humidity inside the head can contribute to mood disorders. He recognized that this occurs when the amount of breath changes: happiness increases the breath, which leads to increased moisture inside the brain, but if this moisture goes beyond its limits, the brain would lose control over its rationality and lead to mental disorders. He also wrote about symptoms and treatments for nightmare, epilepsy, and weak memory.
Unhammad made many careful observations of mentally ill patients and compiled them in a book which "made up the most complete classification of mental diseases theretofore known." The mental illnesses first described by Najab include agitated depression, neurosis, priapism and sexual impotence (Nafkhae Malikholia), psychosis (Kutrib), and mania (Dual-Kulb).
Unhammad also listed nine classes of psychopathology. This included the earliest description of Souda a Tabee (febrile delirium), which was in turn subdivided into Souda where patients showed impairment of memory, loss of contact with the environment, and childish behaviour; and Jannon (agitated reaction) which occurs when Souda reaches a chronic state and is characterized by insomnia, restlessness and sometimes "beast-like roars.
In the Encyclopedia of the Brethren of Purity (10th century), the Brethren of Purity discussed the process of thought, and wrote that the thinking process begins with the five external senses which send messages through the nerves to the brain, which processes the messages in different locations of the brain.
Avicenna discovered the cerebellar vermis—which he named "vermis"—and the caudate nucleus, which he named "tailed nucleus" or "nucleus caudatus". These terms are still used in modern neuroanatomy. He was also the earliest to note that intellectual dysfunctions were largely due to deficits in the brain's middle ventricle, and that the frontal lobe of the brain mediated common sense and reasoning.
Ibn al-Nafis (1213-1288), in his Commentary on Anatomy in Avicenna's Canon, corrected some of the erroneous theories of Galen and Avicenna (Ibn Sina) on the anatomy of the brain. Ibn al-Nafis quoted an error made by Galen, who believed that "blood reaches the brain itself at the section called forebrain through the duramater which divides the vault longitudinally into two equal halves at the sagittal suture." Ibn al-Nafis criticized this theory and corrected it as follows:
Ibn al-Nafis corrected another theory on the nerves stated by Avicenna, who believed that the glossopharyngeal nerve, vagus nerve and accessory nerve arise from the nerve ganglion and that they are attached to the sigmoid and facial nerves through membranous fascia so that these five nerves look like one nerve emerging as three branches from the back foramen lacerum. While experimenting with this theory, Ibn al-Nafis performed the earliest known dissection on the human brain, after he made the following correction to the theory:
Another example was Galen's incorrect theory on the optic nerve, in which he stated that the optic nerve "which comes from the right side of the brain goes to the right eye, and the nerve which comes from the left side goes to the left eye." Ibn al-Nafis also proved this theory wrong and stated:
Avicenna also discovered a condition resembling schizophrenia which he described as Junun Mufrit (severe madness), which he clearly distinguished from other forms of madness such as mania, rabies, and manic depressive psychosis. He observed that patients suffering from schizophrenia-like severe madness show agitation, behavioural and sleep disturbance, give inappropriate answers to questions, and in some cases are incapable of speaking at times. He wrote that such patients need to be restrained, in order to avoid any harm they may cause to themselves or to others. Avicenna also dedicated a chapter of the Canon to mania and rabies, where he described mania as bestial madness characterized by rapid onset and remission, with agitation and irritability, and described rabies as a type of mania.
In The Canon of Medicine, Avicenna extended the theory of temperaments to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." Avicenna's work is thus considered by some to be a "forerunner of twentieth century psychoanalysis."
Ibn Zuhr (Avenzoar) gave the earliest accurate descriptions on certain neurological disorders, including meningitis, intracranial thrombophlebitis, and mediastinal tumours, and made contributions to modern neuropharmacology. Averroes suggested the existence of Parkinson's disease and attributed photoreceptor properties to the retina.
In the Book of Optics, Ibn al-Haytham also developed the "concept of a sensory core that interprets visual stimuli" and which was "highly sophisticated, incorporating mathematical, anatomical and physiopsychological components."
Omar Khaleefa argues that Ibn al-Haytham is also a "founder of psychophysics", a distinct subdiscipline of psychology, though this is a minority opinion. Psychophysics is a battery of quantitative statistical and mathematical methods of relating changes in physical stimulus magnitude to perception. Ibn al-Haytham made many subjective reports regarding vision, though there is no evidence that he used quantitative psychophysical techniques. The psychophysicist Craig Aaen-Stockdale has written a rebuttal to Khaleefa's arguments, noting that the claim for Ibn al-Haytham being the ‘founder of psychophysics’ "rests upon unsupported assertions, a conflation of psychophysics with the wider discipline of psychology, and semantic arguments over what it is to ‘found’ a school of thought.
In The Book of Healing (1027), Avicenna discussed the mind, its existence, the mind and body relationship, sensation, perception, etc. He wrote that at the most common level, the influence of the mind on the body can be seen in voluntary movements, in that the body obeys whenever the mind wishes to move the body. He further writes that the second level of influence of the mind on the body is from emotions and the will. As a thought experiment, he states that if a plank of wood is placed as a bridge over a chasm, a person could hardly creep over it without falling if that person only pictures himself/herself in a possible fall so vividly that the "natural power of limbs accord with it." He also writes that strong negative emotions can have a negative effect on the vegetative functions of an individual and may even lead to death in some cases. He also discusses hypnosis, which he refers to as al-Wahm al-Amil, distinguishing it from sleep. He states that one could create conditions in another person so that he/she accepts the reality of hypnosis.
Ibn al-Nafis (1213-1288) identified the "psychic faculties" with cognition, sensation, imagination, and animal locomotion, and disproved Aristotle's notion that these come from the heart rather than the brain through observation. After Ibn al-Nafis empirically discovered that the brain and nerves are cooler than the heart and arteries, he concluded that the psychic faculties come from the brain on this basis. He further wrote that it is the brain which controls sensation, movement and cognition.
Ibn Khaldun (1332–1406), considered a father of sociology and the social sciences, was another Muslim scholar who significant contributions to the area of social psychology. His book Muqaddimah (known as Prolegomena in the West) was a classic on the social psychology of the peoples of the Arabian Peninsula, particularly the Bedouins.
In animal psychology and musicology, Ibn al-Haytham's Treatise on the Influence of Melodies on the Souls of Animals was an early treatise dealing with the effects of music on animals. In the treatise, he demonstrates how a camel's pace could be hastened or retarded with the use of music, and shows other examples of how music can affect animal behaviour, experimenting with horses, birds and reptiles. Through to the 19th century, a majority of scholars in the Western world continued to believe that music was a distinctly human phenomenon, but experiments since then have vindicated Ibn al-Haytham's view that music does indeed have an effect on animals.
He also made important advances in the understanding of the chronic fatigue syndromes in general, the biopsychosocial model, medical sociology, neurology, psychosocial development, and neurochemical pathology. His "biopsychosocial perspective" of fibromyalgia and other chronic fatigue syndromes is the "only way to synthesize the disparate contributions of such variables as genes and adverse childhood experiences, life stress and distress, posttraumatic stress disorder, mood disorders, self-efficacy for pain control, catastrophizing, coping style, and social support into the evolving picture of central nervous system dysfunction vis-a-vis chronic pain and fatigue."