Mean ± SE preference scores of male and female rats for water, MSG, and MSG + LA (A and C) and for water and two bottles of MSG (MSG 1 = MSG bottle 1 and MSG 2 = MSG bottle 2; B and D). For each MSG concentration: significantly greater than MSG and water (a), significantly greater than MSG and MSG + LA (b), significantly greater than water (c), and significantly greater than MSG (d).