The Function and Type categories

The empirical studies on the Function and Type values often focused on specific values. Accordingly, below the empirical findings are described for the single Function values.

Emphasis

The verbal IQ but not the Performance IQ correlated positively with the pro-portion of time spent with emphasis gestures, specifically with Type values bimanual batons, bimanual superimposed, and right hand back-toss move-ments. Since these gestures accompany speech it is highly plausible that they correlate positively with the Verbal IQ. Individuals with a high Verbal IQ show a high competence in verbal functions and language skills and accord-ingly, they use those gesture Function values that support speech.

The results for this Function value as well as for the Function values de-scribed below, evidences that the different Function values are associated with different forms of intelligence.

Egocentric deictic

An egocentric deictic indicates where something is located by using an egocen-tric frame of reference. The gesturer is the point of reference. Egocentric deic-tics can often be observed in psychotherapy sessions when patients refer subjec-tively to other persons or to symptomatic parts of their body.

In a psychotherapy patient with eating disorders, the use of egocentric deictics in the course of the psychotherapy was explored as an indicator of changes in the relationship to the significant other (Lausberg and Kryger 2011).

Psychodynamically, at the beginning of the therapy, the patient hardly differen-tiated between herself and her mother. When referring to her mother in gesture, she localized the mother in the gesture space close to the body center by using egocentric deictics. At the end of therapy she projected her mother distant from her body by pointing to the left gesture space. This change in the localization of the mother in the gesture space as evidenced by the egocentric deictics con-curred with the psychodynamic development. At the end of the therapy the pa-tient experienced herself and her mother as separate persons.

Another patient referred to her symptom (lump in her throat) reliably by per-forming egocentric body-deictics (Lausberg, 2011). She almost induced the symptom by pressing the index in the throat. The therapist implicitly adopted her gesture and reliably displayed the egocentric body-deictic when referring to the patient's symptom. However, in the course of the therapy he gradually trans-formed the concrete body-deictic into a form presentation gesture that represent-ed the symptom in an abstract manner. Thus, according to the NEUROGES Function model there was a gradual development on the Function axis from left to right. The egocentric body-deictic that referred to a concrete part of the body was transformed into a form presentation gesture that symbolically represented the symptom. The independently conducted discourse analysis of the doctor - patient interaction (Koerfer, 2011) revealed that psychodynamically the patient understood by and by that she had no problem with the throat but that she was afraid of school.

Egocentric direction

In the intelligence experiment, the verbal IQ but not the Performance IQ cor-related positively with the proportion of time spent with bimanual egocentric direction gestures. Egocentric direction gestures do not present something but they often show a direction complementary to the verbal utterance. As pro-posed above (see emphasis) individuals with a high Verbal IQ, who have a high competence to express themselves verbally, use those gesture Function values that support the verbal statement.

Pantomime gestures

In split-brain patients, Lausberg et al. (2003) demonstrated that pantomime ges-tures with tool in hand can be generated in both hemispheres while only the left hemisphere is competent to execute them without tools. The authors suggested that the generation of pantomime gestures with an imaginary tool in hand relies on the specifically left hemispheric competence to link the movement concept for tool use with the mental representation of the tool. They proposed a hierar-chy of object-oriented action with tool > pantomime with tool > panomime with hand-as-object (the hand itself represents the tool) > pantomime with imaginary object (pantomime - enclosure, i.e., holding the imaginary object in hand when demonstrating tool use).

Subsequent neuroimaging studies with functional Magnetic Resonance Imag-ing (fMRI) and with Near Infra-Red Spectroscopy (NIRS) supported the propo-sition that the different subtypes of pantomime gestures are associated with dif-ferent cognitive processes (Lausberg et al. 2010; Helmich et al. 2011). Panto-mime with tool in hand was associated with bi-hemispheric activation. In con-trast, pantomime - enclosure gestures were accompanied by left hemispheric ac-tivation and pantomime - hand-as-object by right hemisphere activation. The findings support the propsed hierarchy of different subtypes of pantomimes.

Pantomimes with tool in hand, which are most akin to object-oriented actions, seem to be cognitively the simplest ones. Both hemispheres are able to execute them. Pantomimes in which the hand itself represents the tool can be generated in the right hemisphere. They do not require abstract cognitive operations, i.e., linking a mental representation of the tool to the movement concept. Finally, pantomimes which require that the hand acts with an imaginary object in hand are cognitively the most complex ones. In fact, their production crucially de-pends on a specific left hemispheric competence.

In the GO/VG experiment, in the Gestures Only condition (GO) as compared to the Verbal condition (VG), there were more pantomime units. Since the stimuli depicted individuals during everyday actions, it was likely that the participants adopted the egocentric perspective and thus, that they chose pantomime gestures to depict the action. In contrast, in the VG condition, the action per se was de-scribed verbally and relatively more non-presentative Function values were dis-played. The hands were used significantly more often for emotion/attitude movements and for subject-oriented actions.

Presentation gestures

Wartenburger et al. (2010) related cortical thickness as measured with structural Magnetic Resonance Imaging (MRI) to hand movement behaviour during a ge-ometric analogy task. They found a larger cortical thickness in the left Broca’s area and transverse temporal cortex in those participants who produced

presen-tation gestures as compared to those who did not. In particular, the first group displayed more motion quality presentation gestures. The findings support the NEUROGES Function model proposing that presentation and particularly mo-tion quality presentamo-tion gestures rely on complex cognitive processes. The adoption of mento-heliocentric cognitive perspective relies on the competence for abstract thinking.

This proposition is further supported in a study by Sassenberg et al. (2011). In-dividuals scoring high in fluid intelligence showed a higher accuracy in a geo-metric analogy task and they produced more gestures - as identified by the Func-tion category - when relating to the most relevant aspect of the task. More spe-cifically, their gestural behaviour was characterized by a high freqeuncy of mo-tion quality presentamo-tion gestures. The correlamo-tion of this Funcmo-tion value with a high fluid intelligence strongly suggests the proposition that it relies on complex cognitive operations.

In the intelligence experiment, the Verbal IQ but not the Performance IQ cor-related negatively with the proportion of time spent with left hand and right hand spatial relation presentation gestures. Spatial relation gestures are as-sumed to be associated specifically with visuo-constructive competence. As suggested above, individuals with a high VIQ display rather those gesture Function values that support speech and than gesture Function values that pre-sent concepts.