Affect attunement: affective accompaniment in tune with the other's activity, such as voiced by mothers when watching the infant child playing. Daniel Stern, who introduced this term, asked mothers in an experiment to overplay or underplay their accompaniment (which some of them found difficult). When the mother made herself get out of tune, the child would stop playing and turn to look at the mother.

Allocentric map: term used by John O'Keefe to distinguish place-oriented memory in animals such as rats (involving hippocampus), determined by where they had been in the landscape, and independent of the direction of their gaze, i.e. transcending the view-orientation linked to egocentric body coordinates of the animal.

Altercentric: term introduced by Stein Bråten to characterize the other-centered perception and mirroring of movements which he has identified in human infants in face-to-face situations, for example when they reciprocate the spoon-feeding to which they have been subjected, reflecting the opposite of egocentric perception of the caretaker's feeding.

Altercentric participation: ego's virtual participation in Alter's act as if ego were a co-author of the act or being hand-guided from Alter's stance. This is sometimes unwittingly manifested overtly, for example, when lifting one's leg when watching a high jumper, or when opening one's own mouth when putting a morsel into another's mouth, and differs from perspective-taking mediated by conceptual representations of others.

Alteroception: term introduced by Colwyn Trevarthen for infants' direct perception of others' body orientation and movements (corresponding to our innate capacity for perceiving own body orientation and movements in proprioception), and used by Stein Bråten to define the mirror reversal entailed by altercentric perception in face-to-face situations as inverted alteroception.

Autopoiesis: term (composed of the Greek terms for self (auto) and production (poiesis)), introduced by Humberto Maturana and Francisco Varela to characterize the self-productive organization of a living system, such as the cell or the individual organism, involving processes interlaced in the specific network of production of components which realizing the network that produced them constitute the system as a unity. In a modified sense the term is used by Niklas Luhmann to characterize the social system, such a social organization or a society, as communicatively closed, reproducing itself and the components that constitute it by internal communication, maintaining its boundary in a self-referential way.

Behavioural re-enactment design: developed and used by Andrew Meltzoff in experimental studies of intention reading in infants who upon watching the model attempt a target action, such a pulling a dumbbell-shaped object apart, re-enact by pulling it apart.

Baldwin effect: stressing mechanisms of learning by imitation, supplementary to the process of natural selection of which they are a genetic product, Baldwin (1895) proposed that such mechanisms reflect back on genetic evolution and speed it up by producing an even more favourable population distribution.

Chirality: term (from the Greek word for 'handedness') for the (a)symmetry found in nature in structural pairs of semblant forms in which one is a mirror image of the other. This is illustrated by the relation between the left and the right hand (only if one of them is reflected by a mirror do they become identical in form), and believed by Bråten to apply to the structural relation between the brain systems that support the bodily self and virtual other, enabling mirroring of actual others.

Circular reaction: term introduced by J. M. Baldwin to characterize circular self-imitation in the infant who takes pleasure in repeating activities found pleasurable.

Circular re-enactment: imitation involving the other -- actual or virtual. While the infant's virtual other is involved in self-imitative circular reaction, the same operational format is posited to apply when imitating others, i.e. what the infants has experienced doing with an actual other, the infant will attempt doing with the infant's virtual other.

Companion space: term used by Bråten, Kugiumutzakis, and others to denote the intersubjective phenomenological space of mutual awareness between two participants, in which the bodily self perspective is complemented by a companion perspective -- actual or virtual --, enabling transformation in the same operationally closed format in these two cycles:
(i) engagements with actual others who fill the companion space;
(ii) self-engagement (with one's virtual other) re-enacting the format of (i)..

Double video(replay) technique: experiment designed by Lynne Murray to test the adult and infant reactions when each unwittingly is faced with a replay of the partner from a previous live sequence of happy protoconversation, when interlinked by monitors and loudspeakers.

Emotional memory: term used by Joseph LeDoux for emotional processing and "storing" in brain systems and pathways bypassing the neocortex, based inter alia on his studies of fear conditioning in rats. Maintained by subcortical circuits, emotional memories may be indelible.
E-motional memory: composite term (combining the folk sense of being 'moved by' and the root sense 'out-of-motion') proposed by Stein Bråten for the procedural memory of having co-enacted -- virtually or actually -- the goal-directed movements of others, evoking in the learner shared vitality affect contours and inviting circular re-enactment in similar situations.

Evoked companion: term used by Daniel Stern for an internal other-representation, evoked in the child's self-dialogue and in engagements with actual companions.

Felt immediacy: the mode of directly perceiving own or others' body movements and orientation in presentational immediacy, as in proprioception and alteroception, differing from perception in re-presentational mediacy that is mediated by symbolic and conceptual distinctions.

Intersubjective communion: mutual engagement between subjects who consensually attend and attune to one another's emotive states, expressions and gestures in a prereflective and nonverbal mode of felt immediacy. Discovering such reciprocal and motivated occurrences in early infant-adult interplay, Colwyn Trevarthen terms this primary intersubjectivity, distinguished from the stage of secondary intersubjectivity when objects of joint attention are brought into play (at around nine months of age), precursory to verbal communication.

Learning by altercentric participation: imitational learning by Ego's virtual participation in Alter's act from Alter's stance as if Ego had been facing the same direction or been hand-guided, and which in face-to-face learning situations entails perceptual mirror reversal of Alter's enactment, giving rise to shared temporal vitality (affects) contours, reflecting the manner in which the enactment is felt to be virtually co-enacted and the feeling that directs the co-enactment, enabling circular re-enactment from e-motional memory of such virtual co-enactments.

Mimetic culture: term proposed by Merlin Donald to characterize the patterns of imitational transfer and creative re-enactment that may have distinguished the Homo erectus culture from the previous stage of primate patterns relying on episodic memory.

Mirror neurons: neurons that fire at the sight of another individual's performing an act, for example of grasping a morsel, discovered in the macaque monkey brain by Giacomo Rizzolatti and his group, and suggested by other studies to be operative in a 'mirror system' also in the human brain, involving the Broca's area which not only support speech but is also involved in hand rotation and imagination of hand rotation (cf. Rizzolatti & Arbib 1998).

Model power theorem: the conjunction of the simulation version of theory of mind and the Conant-Ashby theorem (every good regulator of a system must be a model of that system) implies in certain conditions the following: if you regard the other as the source of the only valid model of a domain D and try to overcome your subordination, in a closed interaction situation of decision-making on D, by adopting the other's model, you thereby enhance the other's control by giving him the power to simulate even your simulations (Bråten 1973c).

Presentational immediacy: term introduced by A.N. Whitehead to distinguish such a primary mode from cartesian modes of representational mediacy (cf. also felt immediacy).

Protoconversation: term introduced by Mary C. Bateson on the basis of her analyses of filmed infant-mother interplay to denote the way in which such interplay already in the second month of life had some of the characteristics, including turn-taking, of a verbal conversation.

Secondary intersubjectivity: term introduced by Trevarthen and Hubley to distinguish the stage (around nine months of age), when the infant is motivated to join the other in a shared object-recognition inviting co-operation in object-oriented task performance, from the stage of primary intersubjectivity (in the first months of life) in which there is mutual subject-to-subject orientation, with little or no shared object-orientation..

Theory of mind: the social-cognitive ability to imagine or simulate others' minds and emotions (the simulation version) or to draw inferences from a theory of other minds (the theory version), attributed by to children by 3 or 4 years of age (see for example contributions in Astington, Harris and Olson (eds. 1988) and in Whiten (ed. 1991)).

Thomas theorem: proposed by W.I. Thomas to this effect: if one defines a situation as real, then it becomes real(ized) as a result.

Virtual Other (Virtual Alter): an innate non-specific companion perspective postulated by Stein Bråten to complement the bodily self perspective with the operational efficiency (virtus) of an actual companion perspective, and inferred to enable alteroception and altercentric mirroring.

Vitality Affects: term introduced by Daniel Stern to distinguish from categorical and discrete emotions (such as surprise, anger, etc.) the more subtle and continuous life feeling flow accompanying activities, including shared activities.

Vitality Contour: term introduced by Daniel Stern for the temporal contour of feeling flow patterns with a characteristic intensity time-course of vitality affects reflecting the manner in which an activity has been enacted and the feeling that directs the enactment.

1 See also pertinent definitions in the glossary in Children with Autism (Second edition) by Trevarthen, Aitken, Papodi & Robarts (Jessica Kingsley 1998:313-330), and in The Present Moment in Psychotherapy and Everyday Life by Daniel N. Stern (Norton 2004:241-247). Scandinavian readers may also be referred to the glossary in Stein Bråten: Kommunikasjon og samspill fra fødsel til alderdom (Tano Achehoug 1998:272-284; Dafolo Forlag: 272-282; Universitetsforlaget 2004:304-318), og Dialogens speil i barnets og språkets utvikling (Abstrakt Forlag 2007:313-323).