H

Heritability: the proportion of the variance of a particular trait in a population that can be traced to inherited factors. The heritability ratio is calculated by dividing the genetic variability by the total variability plus the genetic variability. The genetic variance can be calculated by using concordance rates.

Hierarchy of Needs: Abraham Maslow's model of levels of human motivations, starting with the purely physiological at the bottom and concluding with the transcendental at the top. The 8 levels are:-

• Transcendence - see separate entry
• Self-Actualisation* - see separate entry
• Aesthetic Needs - for symmetry, order and beauty
• Cognitive - the need to know and understand
• Esteem* - to achieve, be competent, gain recognition and approval
• Belonging/Love Needs* - to affiliate with others and be accepted
• Safety* - from danger
• Survival* - at a purely physiological level

Those levels marked * were in the original 1943 Hierarchy. Cognitive, Aesthetic and Transcendence needs were added after his death from discussions in his later writings. Maslow's work provided the blueprint against which Clare W Graves originally tried to match his data and several key Maslowian

concepts survive right through the Graves Model into Spiral Dynamics. It seems highly likely that Graves' own research may have influenced some of Maslow's thinking in the late 1960s.

Hindbrain: evolutionarily the oldest part of the brain, it contains the cerebellum, pons and medulla oblongata.

Holon Theory: developed by philosopher Arthur Koestler as the basis for what he hoped would become a broadly integrative approach to science, the concept has been taken up and popularised by Ken Wilber. A holon - sometimes called a part/whole - is a unit complete and autonomous in itself yet part of a bigger holon. Eg: an atom is complete in itself but part of a molecule and a molecule is part of an element. Koestler called such hierachies of holons being part of more complex holons being part of even more complex holons, etc, 'open hierarchical systems'. Wilber calls them 'holarchies'.

Homeostasis: having a steady or consant state. An example of homeostatic control is the work of the thermostat in a central heating system in maintaining a constant temperature.
The term is used primarily in Psychology to describe the action of the parasympathetic branch of the autonomic nervous system in returning the body to an unstressed condition after the sympathetic branch has aroused it.
It is also used to describe the return to a state of not being hungry after a state of being hungry has been satisfied through the action of eating.

Hormones: chemical substances produced in large quantities by endocrine glands that affect target organs quite powerfully and can dissipate very quickly. Some hormones, such as noradrenaline, are also neurotransmitters.

Humanistic Psychology: an approach that emphasises the uniqueness of each individual, the capacity to make choices (self-determination, free will) and the drive for Self-Actualisation. Carl Rogers and Abraham Maslow were leading proponents of this approach in the 1950s and 1960s when it was thought of as the 'third force' in Psychology after Psychodynamic Theory and Behaviourism. The 'third force' concept was Maslow's - though he actually perceived the Humanistic approach as reconciling the differences between the Psychodynamic and Behaviourist approaches. (In this idea of reconciling other approaches, Maslow was yet again prefiguring Clare W Graves.)