Diminished Representational Momentum for Physical States in Patients with Depressive Disorder

The representational momentum for physical state changes refers to the fact that we remember objects as more changed in physical state than they actually were. It has been well documented that depressive disorder is associated with impairment of time perception. Thus, the present work was conducted with the aim to investigate the representational momentum for physical state changes in patients with depressive disorder, firstly. Forty patients with depressive disorder and forty-two healthy controls were administrated with the task of representational momentum for physical state changes and task of time perception. The stimulus comprises 10 videos showing object state changes (e.g., ice melting). During playing, the video would stop and immediately be obscured by mosaics at a specific point. Participants select from three detection images (the exact frame of the video just be masked, the frame after that, and the frame before that) to test representational momentum and estimate the duration of the video in seconds to test time perception. The depressive group showed diminished representational momentum (i.e., lower scores on the task of representational momentum) than normal controls (U = 215.00, Z = -5.83, p < 0.001). In addition, the scores on the task of representational momentum were significantly positively related with the scores on the task of time perception among depressive group (r = 0.446, p = 0.004). The findings indicate that patients with depressive disorder may exhibit diminished representational momentum for physical states, which may be correlated with their impairment of time perception.