A heuristic[1] or heuristic technique (problem solving, mental shortcut, rule of thumb)[2][3][4][5] is any approach to problem solving that employs a pragmatic method that is not fully optimized, perfected, or rationalized, but is nevertheless "good enough" as an approximation or attribute substitution.[6][7] Where finding an optimal solution is impossible or impractical, heuristic methods can be used to speed up the process of finding a satisfactory solution.[8][9] Heuristics can be mental shortcuts that ease the cognitive load of making a decision.[10][11][12]