In this study we explore the sources of object-specific effects in representational momentum (RM). "Object-specific effects" refers to the elicitation of different patterns of RM by different objects. We examined whether object-specific effects could be produced by an object's conceptual context, visual features, or their interaction. The conceptual context was composed of the object's label with, in some cases, a description of the object, plus experimental trials requiring the participant to identify the object. In addition, we examined whether the contribution of visual features to object-specific effects came from one particular visual feature previously linked to RM (pointedness), or from the object's overall appearance. Our results show that generally, the stimulus' overall appearance must be consistent with its conceptual context for related conceptual knowledge to produce object-specific RM effects. These experiments therefore provide evidence that knowledge particular to an object, or its category, unconsciously affects mental transformations.