Preliminary study of visual perspective in mental time travel in schizophrenia

Highlights

• Schizophrenia patients showed less field visual perspective in mental time travel.

• Schizophrenia patients showed reduced specificity in mental time travel.

• Remembering the past and imagining the future share similar pattern.

Abstract

This study explored specificity and visual perspective of mental time travel in schizophrenia. Fifteen patients with schizophrenia and 18 controls were recruited. Participants were asked to recall or imagine specific events according to cue words. Results showed that schizophrenia patients generated fewer specific events than controls, the recalled events were more specific than imagined events. Schizophrenia adopted less field perspective and more observer perspective than controls. These results suggested that patients with schizophrenia were impaired in mental time travel both in specificity and visual perspective. Further studies are needed to identify the underlying mechanisms.

Introduction

Mental time travel refers to project oneself into the past to re-live the past or into the future to pre-live the future (Suddendorf and Corballis, 1997). This ability is important for our daily living, for example, thinking about future allows one to consider potential consequences before acting and to prepare for the future (Schacter and Addis, 2007). Schizophrenia patients are impaired in mental time travel (Corcoran, 2010). However, most of the previous studies in schizophrenia were on past-oriented mental time travel, i.e., autobiographical memory. A meta-analysis showed that schizophrenia were impaired in autobiographical memory, such as reduced specificity (Berna et al., 2015). Patients tend to generate fewer specific events that happened at specific time and place and lasted no more than one day.

Visual perspective, a phenomenological characteristic, also played an important role in mental time travel (Sutin and Robins, 2008). People usually recall events from a field perspective (see what happens in his/her own eyes) rather than an observer perspective (see the events from outside as an observer). Potheegadoo et al. (2013) found that schizophrenia patients generated autobiographical events less from the field perspective and more from the observer perspective. These indicated that patients had weakened sense of being an actor in their past events.

Several studies examined the future-oriented mental time travel (future thinking) in schizophrenia, and results indicated that patients also showed reduced specificity when thinking about possible future events (D'Argembeau et al., 2008, Painter and Kring, 2016, Raffard et al., 2016). Only one study has been conducted on visual perspective in future thinking in schizophrenia and found contrary to autobiographical memory, they did not show less field perspective than controls (Raffard et al., 2016), however, it needs further study.

The present study aimed to examine the visual perspective as well as specificity of future thinking in schizophrenia patients. We hypothesized that schizophrenia patients would show reduced specificity in future thinking, but we did not have a specific hypothesis on visual perspective.