to Zajonc, tell us that social contact with others might have an effect on our facial features. Affective neuroscience hypothesis The affective neuroscience hypothesis posits that hedonic mood was linked to the temperature of the brain. This relationship was moderated by venous blood changes, which fluctuated according to changes in the function of the hypothalamus. Zajonc hypothesized that venous blood from the brain was moderated by facial expressions. In turn the blood drained from the brain into the sinus cavities, before flowing into the veins of the body. The heat from the blood of the cavernous sinus is able to influence the temperature of the hypothalamus due to their close proximity. Happy facial expressions cooled the hypothalamus, causing a strengthening of positive emotions. Conversely, negative emotions were caused by the ability of the negative facial expressions to warm the hypothalamus. Zajonc studied this theory by having research participants pronounce vowel sounds that resulted in a facial expression that would result in cool blood and brain patters. Zajonc and his colleagues found that participants assigned more positive evaluations of stimuli This finding was also replicated in rats who had their hypothalamus experimentally cooled or warmed via a small probe. Hypothalamic cooling in rats Zajonc was also interested in manipulation of hypothalamic temperature to see if the attractiveness to stimuli could be moderated by changes in cephalic blood temperature. He created two experiments to examine the attractiveness and pleasure of food in rats during hypothalamic cooling or hypothalamic eating. The first experiment screened for elicitation of feeding. There were 17 male rats with hypothalamic thermodes implanted at the anterior border of the medial hypothalamus as well as two chronic oral cannulae in order to permit taste reactivity testing. In the first experiment there was a screening procedure consisting of an initial habituation phase that lasted 10 days and a test phase that lasted 6 days, A rat was placed once per day in a transparent chamber and its hypothalamic thermode was connected to the water flow and for a 10-minute period, the hypothalamic thermode was cooled by 2.5° in alternating On/Off bins of 15 sec each. Hypothalamic cooling was delivered on days 1,3, and 5 while a behavioral test was run on the second, fourth and sixth days. During hypothalamic cooling, many rats showed enhanced feeding. Zajonc also found that feeding was elicited during hypothalamic cooling but not heating or when the