استفاده از ابزار یک توهم اندازه را نشان می دهد که مکانیزم ادراک خاص را مشخص می کند

In four experiments, participants estimated the sizes of target objects that were either out of reach, or that could be reached by a tool (a stylus or laser pointer). Objects reachable with the aid of a tool were perceived to be smaller than identical objects without a tool. Participants' responses to questioning rule out demand characteristics as an explanation. This new size illusion may reflect a direct impact of tool use on perceived size, or it may stem from the effects of tool use on perceived distance. Both possibilities support action specific accounts of perception.