The fact that blind people can "see" things using other parts of their bodies (31) their eyes may help us to understand our feeling about color. If they can (32) color differences then perhaps we, too, are affected by color unconsciously. By trial and (33) , manufacturers have discovered that sugar (34) badly in green wrappings, that blue foods, are considered (35) and that cosmetics should never be packaged (36) brown. These discoveries have grown into a whole (37) of color psychology that now (38) application in everything from fashion to interior decoration. Some of our (39) are clearly psychological. (40) blue is the color of the night sky and therefore (41) passivity and calmness, while yellow is a day color with associations of energy and incentive. For primitive man, activity during the day meant hunting and attacking, while he saw red as the color of blood and rage and the heat that came with (42) . And green is relevant to passive defense and self-preservation. (43) have shown that colors, partly because of their psychological associations, also have a direct psychological effect. People (44) to bright red show a(n) (45) in heartbeat, and blood pressure; red is exciting. Similar access to pure blue has exactly the opposite effect; it is a (46) color. Because of its exciting of connotations, red was chosen as the (47) for danger, but closer (48) shows that a vivid yellow can produce a more basic state of alertness and alarm, so fire engines and ambulances in some advanced communities are now (49) around in bright yellow colors that (50) the traffic dead.