"'"A verdict of deliberate and premeditated first degree murder requires more than a showing of intent to kill. . 'Deliberation' refers to careful weighing of considerations in forming a course of action; 'premeditation' means thought over in advance. ." . "'Premeditation and deliberation can occur in a brief interval. "The test is not time, but reflection. 'Thoughts may follow each other with great rapidity and cold, calculated judgment may be arrived at quickly.'"'"'" (People v. Mendoza (2011) 52 Cal.4th 1056, 1069.) In contrast, second degree murder is an unlawful killing with malice--either express (intent to kill) or implied (the intentional commission of a life-threatening act with conscious disregard for life)--but without the elements of willfulness, premeditation and deliberation. (See People v. Chun (2009) 45 Cal.4th 1172, 1181.) In People v. Anderson (1968) 70 Cal.2d 15 (Anderson) the Supreme Court "recognizeed the need to clarify the difference between first and second degree murder and the bases upon which a reviewing court may find that the evidence is sufficient to support a verdict of first degree murder . . . ." (Id. at p. 26.) After "setting forth standards, derived from the nature of premeditation and deliberation as employed by the Legislature and interpreted by the Court, for the kind of evidence which is sufficient to sustain a finding of premeditation and deliberation" and analyzing representative cases, the Court set forth the benchmark standard. As summarized in People v. Elliot (2005) 37 Cal.4th 453, "'Generally, there are three categories of evidence that are sufficient to sustain a premeditated and deliberate murder: evidence of planning, motive, and method. . When evidence of all three categories is not present, "a reviewing court requires either very strong evidence of planning, or some evidence of motive in conjunction with planning or a deliberate manner of killing . . . ."'" (Id. at p. 471; see People v. Alcala (1984) 36 Cal.3d 604, 626 "Evidence in only one of these areas most often is insufficient. Where fewer than all three indicia are present, we require 'at least extremely strong evidence of (1) planning or evidence of (2) motive in conjunction with either (1) or (3) deliberate manner of killing.'".) "'But these categories of evidence, borrowed from Anderson "are descriptive, not normative." . They are simply an "aid for reviewing courts in assessing whether the evidence is supportive of an inference that the killing was the result of preexisting reflection and weighing of considerations rather than mere unconsidered or rash impulse."'" (Elliot, at p. 471.)