Psychological research has consistently reaffirmed that, across development, humans are meaning makers. Our ability to interpret stimuli from our environment, glean information, process, communicate, and respond accurately is central to our success in navigating in the world around us. Gestures, movements in the air that communicate ideas, are one way in which we receive information, communicate, and react to our external world.
Novak, Wakefield, and Goldin-Meadow explored action interpretation in their publication What makes a movement a gesture? Previous studies have indicated that actions can be interpreted in three ways: 1) movement toward an external goal 2) movement for its own sake, and 3) representational movement also known as a gesture. The researchers conducted two experiments. In study 1, they hypothesized that when presented with a scenario in which an actor actually manipulates objects, the action will be interpreted as movement toward an external goal. Whereas if they actor gestures in the air without touching the object, they predicted that this would be viewed as representational rather than just movement done for its own sake. They showed participants a video in which an actor engaged in movement. In the first scenario, the actor interacted with the objects and the majority of participants interpreted this as having an external goal. In the second scenario in which objects were present but the actor gestured in the air, a majority of participants interpreted this a having a representational goal. In the third scenario, the actor motioned in the air with no objects present, and a majority of participants interpreted this as having a movement-based goal or movement for its own sake.
Using the same paradigm as before, in study 2 they aimed to see what effect context clues had on results. They varied the shape of the hand of the actor (grasping the object or an unrelated shape) when gesturing and the presence or absence of unintelligible speech. With this, they hypothesized that participants would be more likely to interpret movements as gestures if the hand shape matched the object or when speech was present with a gesture. Their results indicated that movements were interpreted as gestures more often when the hand was in a grasping shape. Speech, however, did not affect whether a movement was interpreted as a gesture across the board.
With the complexity of gesture interpretation in mind, Walther and Mittal (in their article Why We Should Take a Closer Look at Gestures) argue that such research is relevant for better understanding of schizophrenia. Abnormal gestures due to motor disturbance and thought disorders are commons symptoms in both the prodromal and active phases of schizophrenia. The authors identify three different aspects of gesture that can be considered: perception, performance, and interpretation. In particular, gestures that confer nonverbal communication or accompany speech are of interest. This is to say, this requires both motor activity and higher cognitive processing. Poor social functioning in schizophrenia may be explained partly by these motor and cognitive deficiencies. Studies have demonstrated that schizophrenic patients tend to gesture less and have difficulty performing and perceiving gestures. While those with schizophrenia may have trouble producing gestures due to catatonia, Parkinsonisms, or other neurological failures, they may also interpret gestures in line with their delusions, whether they have erotomanic, grandiose, jealous, persecutory, somatic, or mixed content.
The neurocorrelates of gestures have also been studied and involve the brain regions associated with action planning, motor execution, and perception. Namely, the left inferior frontal gyrus, inferior and superior parietal lobules, premotor cortices, primary motor cortex, supplemental motor area, orbitofrontal cortex, superior frontal gyrus, and language areas in the temporal lobe have been implicated. Given this, little is known about what activation (due to perceiving, performing, and interpreting gestures) may look like in an individual with schizophrenia. One study of gesture interpretation found that schizophrenic patients had more difficulty making meaning of abstract gestures. In addition, they found decreased activation in language areas and abnormal connectivity between the inferior frontal gyrus and superior temporal sulcus. With these findings, the authors argue that future research that targets the neurocorrelates of gesture in affected individuals would allow for a better understanding of the psychopathology of schizophrenia. Such a pursuit could lend itself to identifying the dysregulation of cognitive processes that may contribute to certain psychotic symptoms. Demonstrating the importance of such investigations, utilizing the literature of gesture interpretation in “normal” individuals (such as Novak, Wakefield, and Goldin-Meadow’s work) could be used as a standard to better understand deviations in gesture perception, performance, and interpretation in schizophrenic individuals.
References
Novack, M., Wakefield, E., & Goldin-Meadow, S. (2016, January). What makes a movement a gesture? Cognition, 146, 339-348. doi:10.1016/j.cognition.2015.10.014
Walther, S., & Mittal, V. (2016, March). Why We Should Take a Closer Look at Gestures. Schizophrenia Bulletin, 42(2), 259-261. doi:10.1093/schbul/sbv229
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