Human Pheromones and the Biology of Behavior
June 21, 2011 | James Kohl
A seemingly otherwise intelligent discussant in the Yahoo group on human ethology (for the biology of behavior) turned to sarcastic flaming after I wrote that “The biology of human behavior is the gene-cell-tissue-organ-organ system pathway that links sensory input to behavior.”
Later he brought to bear his knowledge of behavior analysis and wrote: “The existence and success of behavior analysis is proof that a natural science of behavior can be developed that doesn’t treat behavior as a “symptom” of activity in the alleged mind or in the real but ill-understood brain.” This suggests he does not grasp anything about the biology of behavior, because it includes well-understood brain activity.
“Symptoms” of well-understood brain activity are clearly established via rewards and experience-dependent conditioned preferences that depend on hormonal changes driven by the effects of odors. Food odors and social odors elicit these “symptoms” of activity,and there are sex differences in the social odors. Clearly, the existence and success of behavior analysis is proof that the natural science of behavior depends on treating behavior as a “symptom” of activity in the brain (a “Mind’s Eyes” approach). This activity is well-understood through the use of the Principles of Biology and Levels of Biological Organization that sometimes are ignored.
For example, there are species-specific sex differences that lead to many unanswered questions about sex differences in the behaviors of males and females. These behaviors are often proposed to be falsely dichotomous. My understanding of the development of these supposedly dichotomous sex differences in the brain points to flawed logic in diatribes about definitions of behavior, and about concepts that do not consider the development of hormone-dependent sex differences.
Diatribes and discussions of definitions and concepts, which do not address the genetically predisposed, environmentally-effected, hormone-dependent sex differences in behavior, are a waste of time. This is especially true where appropriate topics for discussion are indicated in the human ethology group’s description. Discussions of definitions and concepts that do not include hormone-dependent sex differences in behavior have little or nothing to do with the biology of behavior, and seem to be inappropriate given the group’s description by The International Society for Human Ethology (ISHE).
The combined approaches of the group’s moderator and of one active discussant lead to discussion and definition of brain-less behaviors, which I perceive to be inappropriate in a group with a human-ethology purpose. In contrast, there are two short papers that clarify how odor-driven differences in brain-driven behavior develop to include sex differences in behavior. Here is the introductory paragraph from the first of the two papers: Synthetic approach to the neurobiology of behaviour. Le Magnen J. Appetite. 1998 Aug;31(1):1-8.
“All behaviour is carried out following the transmission to the brain of convergent information coming from both the internal state of the organism and the environment. Interoceptive and exteroceptive stimuli provide this information to three aspects of each specific type of behaviour: initiation of the behaviour, promotion of a relevant brain state or arousal and driving of performance. Depending on the behaviour, stimuli of initiation may be predominantly either internal and neurally or humourally transmitted to the brain, or environmental and transmitted through sensory pathways. These initiating stimuli define and separate specific behavioural arousal states of the central nervous system. These states are generally designated by terms also used to refer to the subjective feeling associated in man to the initiation of each behaviour: hunger, thirst, fear and sexual arousal for example. A more purely objective terminology is state of stimulation to eat, to drink, to escape etc. Each of these states activates the capacity of a set of external sensory stimuli to drive the behaviour. Activations are both state-dependent and state-specific. They are state dependent: for example, they appear with hunger and disappear with satiety. They are state-specific, i.e. different in hunger, thirst, fear etc. These sensory activations are either inherited or learned. In this learning, the reinforcer is the post-behavioural relief of the initiating state: alleviation of hunger or fear for example–in other words, the success of the behaviour. The effect of this learning (like of all learning) is to transfer to external sensory stimuli a part of the systemic capacity to initiate and to satiate the performance. Thus, the post-behavioural consequences of the performance may be anticipated on the basis of external sensory cues. Activated sensory stimuli become pleasant or aversive. This hedonic colouration, either innate or learned results from efficient execution of behaviour as well. Thereby the renewal of such behaviour is favoured. Thus, one aspect of learning is to memorize only what has become subjectively good or bad, because actively experienced as such. Some details of three basic types of behaviour, feeding, defence and sexual activity, will clarify the above statements and lead to new concepts of the brain mechanisms involved.”
Here is the abstract from the second of the two papers: Reframing sexual differentiation of the brain. McCarthy MM, Arnold AP. Nat Neurosci. 2011 Jun;14(6):677-83.
“In the twentieth century, the dominant model of sexual differentiation stated that genetic sex (XX versus XY) causes differentiation of the gonads, which then secrete gonadal hormones that act directly on tissues to induce sex differences in function. This serial model of sexual differentiation was simple, unifying and seductive. Recent evidence, however, indicates that the linear model is incorrect and that sex differences arise in response to diverse sex-specific signals originating from inherent differences in the genome and involve cellular mechanisms that are specific to individual tissues or brain regions. Moreover, sex-specific effects of the environment reciprocally affect biology, sometimes profoundly, and must therefore be integrated into a realistic model of sexual differentiation. A more appropriate model is a parallel-interactive model that encompasses the roles of multiple molecular signals and pathways that differentiate males and females, including synergistic and compensatory interactions among pathways and an important role for the environment.”
By reading two articles that total 14 pages, behavioral analysts and others who are interested in the biology of behavior, which includes sex differences, could bring their selves to a current understanding of the topic. I am consistently amazed when people choose to live their lives in the past and express opinions on behavioral development that should have died with their long-dead original protagonists / story-tellers. It sometimes seems to me that many people live in a neo-Darwinian age with an ever-present and overriding Freudian psychoanalytic approach to the development of behavior. Have they collectively learned nothing new in the past 70+ to 250+ years.
See also: Human pheromones: integrating neuroendocrinology and ethology. Kohl JV, Atzmueller M, Fink B, Grammer K. Neuro Endocrinol Lett. 2001 Oct;22(5):309-21
The effect of sensory input on hormones is essential to any explanation of mammalian behavior, including aspects of physical attraction. The chemical signals we send have direct and developmental effects on hormone levels in other people. Since we don t know either if, or how, visual cues might have direct and developmental effects on hormone levels in other people, the biological basis for the development of visually perceived human physical attraction is currently somewhat questionable. In contrast, the biological basis for the development of physical attraction based on chemical signals is well detailed.
And see From fertilization to adult sexual behavior. Diamond M, Binstock T, Kohl JV. Horm Behav. 1996 Dec;30(4):333-53.