An excerpt on gorilla sign language for emotions and memories from this paper (bold mine):
Which nonhuman animals may be near-persons like Jenny? Reviewing the evidence, Varner argues that the category includes great apes, cetaceans, elephants, and, perhaps, corvids and parrots. To defend his claim that great apes do not have the kind of episodic memory required to have a biographical sense of one’s past, he examines the evidence provided for believing that Koko, the gorilla, has narrative and uses it to communicate deeply emotional personal memories from the distant past.
Koko was five years old in July, 1976. According to Francine “Penny” Patterson, who worked more closely with Koko than anyone, in 1976 Koko narrated an event that had happened three days prior:
(P = Patterson; K = Koko)
P: What did you do to Penny?
K: BITE.
P: You admit it? (Koko had earlier called the bite a SCRATCH.)
K: SORRY BITE SCRATCH. (Penny shows the mark on her hand; it does resemble a scratch.)
K: WRONG BITE.
P: Why bite?
K: BECAUSE MAD.
P: Why mad?
K: DON’T KNOW
(Patterson & Cohn, 1994, p.282)
Koko’s one and two word responses here, drawn from her knowledge of more than a thousand American Sign Language (ASL) signs, clearly show an understanding of concepts, words, and causal relations (What did you do to Penny? BITE). However, as Varner notes, there is no evidence here of episodic memory, in which one remembers oneself at a particular place at a particular time. Koko is using ASL which, Varner tells us, does not include tenses. Consequently, he observes, “temporal references must generally be inferred from the context, and in these studies, that context is provided by the English sentences uttered by the human trainers” (Varner, 2012, p.155). Varner has his doubts about whether Koko is here communicating a conscious memory of what happened three days ago. Rather, Koko may simply be making signs she knows will succeed in eliciting the responses Koko desires from Patterson.
But if Koko is not capable of expressing memories of events three days in the past, she is able to communicate her emotions. When asked, “How do you feel?” she will respond appropriately, for example, with FINE, or HUNGRY, or SAD. In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years. We are on firm ground, then, in thinking Koko has words and concepts, social communication, rationality in the sense of cause and effect thinking, emotions, awareness, and beliefs and desires. But she does not seem to have the second-order desires, executive control, or autonomy required for a biographical sense of self.
Varner is similarly cautious about long-term memories allegedly recounted by a gorilla, Michael, who was captured by poachers as an infant. Patterson made a video of Michael allegedly recounting this memory of the incident in which Michael’s mother was killed. In the recording we see Michael’s signings rendered in the following captions provided by Patterson: “SQUASH MEAT GORILLA. MOUTH TOOTH. CRY SHARP-NOISE LOUD. BAD THINK-TROUBLE LOCK-FACE. CUT/NECK LIP(GIRL) HOLD” (The Gorilla Foundation, n.d.). Varner, noting the ambiguity of the string of words, observes that “even Patterson’s sympathetic co-author Eugene Linden doubts her claim that Michael was telling the story about his mother’s death” (Ibid, pp.155–156). Varner concludes that in spite of such anecdotes and Patterson’s claim that Michael told her this story on several occasions, there is “no good evidence that apes understand or use language to express thoughts about the non-immediate past” (Ibid, pp.156). If Varner is wrong and Michael is recounting an episodic memory, Michael has an important claim to personhood. If Varner is right, perhaps Michael is just making signs he thinks Patterson is subconsciously nudging him to make, perhaps in Clever Hans fashion. In that event, Michael may not have episodic memories of the traumatic events. Rather, he may only be signing in sequences he has learned satisfy Patterson’s promptings.
Also, for another comparison, children only really start passing the mirror test at around 2 years old.
EDIT: On further consideration, “In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years” seems suspiciously late to me.
An excerpt on gorilla sign language for emotions and memories from this paper (bold mine):
Also, for another comparison, children only really start passing the mirror test at around 2 years old.
EDIT: On further consideration, “In children, internal immediate-state language reporting one’s mood emerges in the third and fourth years” seems suspiciously late to me.