Finding Sarah: 49-Year Reunion with the Chimpanzee of David Premack's Language Studies

Sarah worked in psychological research for decades, and contributed greatly in the study of language and cognition. She participated in countless experiments, lived in an enriched environment, and made a significant impact on both the researchers and research.

I first met Sarah at the University of California at Santa Barbara (UCSB). She was climbing a tree outside the three-story psychology building with her roommate, Gussie. Sarah is an African-born female chimpanzee (Pan troglodytes) who lived and “worked” in an “apartment” on the third floor of the psychology building in David Premack's language and symbolic reasoning lab. David's wife and colleague, Ann Premack (Premack, 1976, pp. 77 and 104) reported that Sarah's language education began in 1967 when Sarah was 6-years-old, and that Sarah participated in language and symbol use until she was about 10. After 2 years at Santa Barbara City College, I enrolled at UCSB in the fall of 1967, where I began work as a trainer for 20 months for David Premack (henceforth referred to as Premack in our discussion). Thus, Sarah was 6-years-old when I first saw her climbing the tree and I was 21-years-old; she was born about 1961. Today she is about 56-years-old, and I am 71! This article is about some of my experiences working with Sarah in Premack's lab, and then, with my coauthor and colleague, Linda Montgomery, our recent search for Sarah and my reunion with Sarah in the summer of 2016 at Chimp Haven in Louisiana.

Sarah was relocated from Africa to Missouri in 1964 where she joined Ann and David Premack. Premack was at the University of Missouri after a position at Yerkes Primate Biology Laboratory at Orange Park in Florida. Sarah was accompanied by another female chimpanzee, unrelated, named Gussie, who was slightly younger. Both had been captured. Their mothers likely were killed by locals to eat, or were sold in the bushmeat trade. At the University of Missouri Sarah and Gussie “lived comfortably in an apartment above David's rat research laboratory” (Premack & Premack, 1983, p. 5). They all came to UCSB in 1965.

Premack was interested in intelligence, in demonstrating the symbolic and reasoning abilities of chimpanzees that “included characteristic features of natural language” (Premack & Premack, 1972, p. 99). In the wild, chimpanzees have an extensive vocal “call system” that communicates emotional states such as fear, distress, and excitement (Goodall, 1986). They also have a rich nonvocal gestural language (Hobaiter & Byrne, 2014). Although chimpanzees are physically capable of producing many sounds found in human language (Lieberman, 2003), they are nonetheless lacking (Kelemen, 1948), and previous attempts to train chimpanzees to imitate human speech sounds have “failed resoundingly” (Premack & Schwartz, 1966, p. 303). What Premack set out to do was to use aspects of human language to demonstrate cognition and symbolic reasoning in the chimpanzee, “not imitation nor even phonology” … “nor isomorphism” (Premack & Schwartz, 1966, p. 303). Language was the medium, one might say, to reveal chimpanzee intelligence. Sarah and Gussie were never food deprived in order to “motivate” them. There was always an ample supply of Purina Monkey Chow available, and edible treats. Premack was very averse to any form of abuse of the chimpanzees. Because he was primarily interested in intelligence, he noted “Such would hardly be an astute procedure for exploring the mind. A starved animal is not necessarily a more thoughtful one” (Premack & Premack, 1983, p. 5).

To circumvent the chimpanzee's inability of produce speech sounds, Premack and a linguist, Arthur Swartz, devised a language apparatus capable of generating sounds, called a joy stick, not unlike that found in today's video games (see Premack & Schwartz, 1966, for a description of this phonetic language system). Except it was much bigger. It was a rotating aluminum-type sphere about the size of a volleyball with a lever on top. I remember seeing this device in the storage cabinet at UCSB. Moving the lever moved the sphere, and, depending on the position of the lever, different sounds were generated. However, the sound generating device was actually very complex and Sarah and Gussie were able only to generate a kind of “babbling” at best, and the joystick was mechanically troublesome. Consequently, Premack abandoned this approach to language and developed another (Premack, 1976).

Premack next devised a type of written language based on words symbolized by colored pieces of plastic. Each word was a specific shape and color, and were about .25 in. thick and varied from 1 to 1.5 in. across or top-to-bottom. Training with the new language system began in 1967 with about four words: a blue triangle was the word apple; a pink square was banana; a blue bar-bell shape was bottle; and a blue clover shape was grape. “This novel language could be seen but not heard and touched but never pronounced. The words did not vanish as do spoken words” (Premack & Premack, 1983, p. 16). A picture of Sarah graced the cover of the October 1972 issue of Scientific American showing some of the plastic words (Premack & Premack, 1972).

This was the time I met Sarah and Gussie, when there were only about four words in their lexicon. I had enrolled as a junior at UCSB in the fall quarter of 1967. I was living with my parents in the city of Santa Barbara near the beach where I surfed whenever there were waves of reasonable height. Prior to 1970, there was no tuition per se for state residents attending the University of California. In 1967 there was an “incidental fee” of $73 per quarter, a “student Center fee” of $6 per quarter, and an “associated students’ fee” of $10. So the total cost per quarter, excluding books, was $83; parking was $25 per year. I could afford college working part-time and living at home. There was a notice on the bulletin board outside the Psychology Department office for a student assistant, a “trainer” or, better termed, a “language instructor” to work with Premack's chimpanzees, likely for around $1.75 an hour.

Premack learned I had a bit of a talent for making and repairing surfboards and could “make” more words out of colored surfboard/boat resin. And so I did. I made about six each of 130–140 distinctly different colors and shapes of plastic to be used as words, many unnamed at the time, and just kept them in storage until Premack needed them. Generally I checked the color and shape for Premack's approval before I cut the shapes with a band saw in the Psychology Department. Premack would then chose the meaning symbolized by each “as ‘exemplars’ of language he hoped Sarah could learn—nouns, verbs, adjectives, pronouns. And quantifiers. Besides, she needed to learn several kinds of sentences—questions and imperatives, compound and complex” (Premack, 1976, p. 77). This was a very creative and fun exercise to design and cut the “words” and then observing Premack link the meaning to each. For example, he asked me to make words for (correct) and (incorrect) such that each was the same shape but were quite opposite in color. I made a black propeller-shape and a white propeller-shape. He said something, quite seriously, like, “Okay, we'll make the white one symbolize (incorrect) and the black one (correct); who knows, we don't want to offend anyone.”

Next I glued steel washers (the little round things with a hole in the center used with bolts and nuts) to the backs of each word so they would stick to a magnetic slate I also made. The magnetic slates, called “language boards” or “writing boards” were about 18 in. × 24 in. and held rows of magnets used to hold metal hand tools in one's workshop or garage. I stacked about 14 of these in rows, put a wooden frame around it, and then filled it flat with resin. I made about four of these. The system worked well. But there were so many words for the trainers to learn, and wherever I could, I used some sort of mnemonic aid that would help us humans, but be of no help to a chimpanzee. For example, each of the trainers had a name represented with a plastic shape, and we wore our name about the neck as a pendant. Sarah's name was in the shape of a number “8,” red, with a little appendage at one end to represent a tail (like a monkey). My name was simply a piece of blue plastic in the shape of a “J,” and Mary's name was a green “M” shape, and so on.

Sarah and Gussie were housed together in their home cage, “a space akin to a two-room apartment” (Premack & Premack, 1983, p. 6). Two walls and the floor were of tile construction and the ceiling and other two walls were made of chain link fencing material. Although Mary, one of the first language trainers and who had the best relationship with Sarah and Gussie, began instruction inside the cage, instruction had to move beyond the reach of Sarah's strong arms for safety considerations as she was maturing. Consequently, the trainers remained standing outside the fencing with the chimps inside, each chimp sitting on separate table-platforms about eight feet apart, and reaching through openings in the fencing to obtain treats or pick up plastic words. One trainer worked with Sarah while a second trainer worked simultaneously with Gussie. Sarah and Gussie usually had about two training sessions daily for about a half hour or more each time.

We began basically with a social exchange whereby the language instructor serves as “giver” or “donor” and the chimpanzee does the “taking” or “receiving” (Premack & Premack, 1983). So, the trainers began by simply giving Sarah and Gussie a variety of bite-size edible fruits, one at a time; they ate and we watched. As it turned out, during these social-feeding exchanges, Sarah and Gussie were always in the role of a receivers and they never gave anything to each other, nor to one of the trainers.

Next, the edible was paired with its associated plastic word, with the word within reach and the fruit/edible just out of easy reach. All Sarah and Gussie had to do was pick up the word and place it on her writing board (each had her own writing board attached [bolted] like one would attach a painting to a wall). When the word was placed on the writing board, they promptly were given the fruit. The point of this was to teach Sarah and Gussie that a unique piece of plastic—a noun in this case—represented a specific edible, and that they needed to place the plastic word on the writing board before receiving the edible. At first Sarah took some coaxing to affix the plastic word on her writing board, but learned by modeling, as the trainers had a writing board as well, and put a duplicate word on their board so Sarah could imitate the procedure. Soon Sarah understood the mechanics of placing words on the writing board, and this procedure became quite automatic. After eating her fruit, Sarah removed the word from her writing board and returned it to the trainer. It was much more difficult to teach Gussie to do this, however.

In order to determine whether Sarah and Gussie had learned a plastic word/edible association, we used a matching-to-sample procedure. Now two different plastic words were placed side-by-side about 4 in. apart within reach, and one piece of fruit in sight but slightly out of reach. One of the two plastic words was symbolic of the edible during prior training. For example, a blue triangle (apple) and a pink square (banana) would be placed side by side with a slice of banana out of reach. Their task was to simply pick up the pink square that symbolized (banana) and place it on their respective language board. If they made the correct choice of picking the pink square, they were given the slice of banana. Placing the plastic word on the writing board was the “language equivalent of our uttering the word ‘banana’” (Premack & Premack, 1983, p. 19). If they made the incorrect choice, the chimp handed back the word and we started over with a new pair of words and a different edible. It was at this stage that we lost Gussie, in the sense that she never quite learned that a unique piece of plastic represented a unique edible.

As it turned out, Gussie was not associating the features of the piece of plastic with the edible that it represented. Instead, she was paying attention to social cues, as was the famous horse “Clever Hans.” Subtle eye movements that the trainer unintentionally emitted apparently helped Gussie often enough to guide her selection in the matching-to-sample task. For example, if a blue clover shape (grape) and a green rectangle (apricot) were presented inches apart with a real grape out of reach behind the words, Gussie would take her long index finger and lower it to within a half inch of the (grape) word, keep it there, look up to the trainer for any sort of twitch of the eye, cracked smile, or whatever. Seeing none, she'd move her finger over the word for (apricot), and look at us again for some subtle cue. She did this repeatedly: Point, look at the trainer for a cue, point to the other plastic word, seek clues, and back and forth until she “saw” what she thought was the tip-off, perhaps in the eyes of the trainer. Somehow, unwittingly, the trainers had been giving Gussie cues. Consequently, Premack decided that all trainers should wear sunglasses to prevent Gussie from responding to any eye cues. The sunglasses didn't bother Sarah at all, but wearing them marked the end for Gussie. Gussie was totally frustrated. If she didn't guess right the first time, the trainer had better beware. She would steal words, bark, hoot, and swing in a rage from the fenced ceiling, and totally disrupt the training session. “Though systematically exposed to the language as Sarah had been, Gussie failed to learn a single word” (Premack & Premack, 1983, p. 4).

Although Sarah was far and away an excellent pupil, and only positive reinforcement procedures were employed, Sarah's education was not smooth and easy. “Sarah learned her first words slowly, only after months of failure …” (Premack, 1976, p. 22). It took Sarah hundreds of trials to “form the first associations between the plastic words and objects” (Premack & Premack, 1983, p. 20). In addition, sometimes the trainers needed to learn a trick or two as well; perhaps we were a bit ethnocentric. At any rate, two examples come to mind. One has to do with her “favorite edibles,” and the second has to do with writing vertically versus horizontally on her writing board.

Many animals have favorite foods. Clearly people, dogs, and cats do. Sarah did too, and she was letting us know her favorite, but we didn't understand at first. For example, in the matching to sample trials, Sarah was typically correct 80% to 85% of the time (Premack, 1976, pp. 32 and 74), regardless whether she was choosing between two, three, or even four plastic words, one of which represented the edible that was out of reach. She'd be incorrect about 15% of the time and we were sure that from hundreds of trials that Sarah knew better. “It then dawned on us that that her poor performance might be due not to errors but to her trying to express her preferences in fruit” (Premack & Premack, 1972, p. 97). Premack, scientifically gifted as he was, had an idea of how to design an experiment to determine why these errors were occurring. First, for a couple of weeks, we made random trials of all the possible pairs of actual edibles, placing one side by side within Sarah's reach, like a slice of apple and, four inches away, a slice of orange. She was allowed to pick one and eat it. Then we'd present a new pair of edibles, and so on, perhaps 30–40 pairs in a session and recorded the edible she selected. This way we established her “preference hierarchy for edibles.” As it turned out, whenever a grape was paired with another edible, Sarah would pick the grape over other paired options. Grape was thus her favorite edible. During independent training sessions, we used a similar procedure to establish Sarah's “preference hierarchy for plastic words.” Here, with no edible in sight, we paired all the plastic words with one another using all possible pairs. Sarah's task was to pick one of the two plastic words and place it on her writing board. When she did so, she received the edible and then handed back the plastic word. A comparison of these two preference hierarchies revealed that “Sarah's choices between the words were much the same as her choices between the actual fruits … and suggest that she could generate the meaning of the fruit names from the” plastic symbols alone (Premack & Premack, 1972, p. 97). For example, Sarah's preferred edible was a grape, and her preferred plastic word was the blue clover symbolizing (grape).

As a side note, one might recall that the United Farm Workers union, led by Cesar Chavez at the time, was protesting the purchase of grapes. This “No Grapes” boycott was at its peak from about 1967 to 1970. Picketers often appeared in front of the local Safeway and Vons super markets throughout Santa Barbara. On the one hand, we did not want to buy grapes, but on the other hand, we needed grapes for Sarah—grapes were her favorite. We compromised, buying half as many grapes as we would have liked to have used in language sessions with Sarah. The trainers took turns going to the grocery store, and tended to go late at night when there wouldn't be any picketers. Can you imagine, leaving the grocery store with a bag of grapes and explaining to the picketer(s) “I'm really sorry, but I need these grapes for my chimpanzee.” I seem to recall saying such on one occasion.

The second example of how we trainers were being ethnocentric and had to reorient our thinking had to do with teaching syntax to Sarah. To begin, Sarah was taught to use the plastic word (give) in short telegraphic sentences. The verb (give) was a green-shaped prism, and this was the first verb we taught her. We used a modified matching-to-sample procedure where two plastic words for an edible were presented side-by-side along with the (give) word next to them. As usual, the matching edible was behind this group of three words, out of Sarah's reach. Sarah's task was to pick up the appropriate word for the edible she saw and, in addition, pick up the word (give), and place them both on her writing board in a left-to-right order, for example: (give) (banana). The syntactic rule was that the verb (give) always preceded the object. But Sarah would not write left-to-right, and she became frustrated in our attempts to correct her and get her to imitate what we wrote on our writing boards in the “correct” left-to-right sequence. It finally occurred to us that Sarah was writing in the correct order, but top-down, vertically, not horizontally. She preferred to write vertically. Once we adjusted to her vertical sentence style, teaching more verbs and longer strings of words went relatively smoothly, but certainly not fast. Soon there were vertical strings of words such as: (Jim) (give) (grape); (Mary) (give) (apple) (Sarah); (Randy) (insert) (apple) … (in a can of powdered sugar so the apple became really yummy when given to Sarah). After teaching the second verb, “insert,” the verbs “cut” and “wash” were added to Sarah's lexicon (for more detail, see Premack, 1976, pp. 76–77 and 97–102). “Although Sarah might be considered slow in acquiring word order, once she acquired it she retained it well” (Premack, 1976, p. 102).

One string of words Sarah learned rapidly was (Jim [or the name of another trainer]) (give) (key) (Sarah). After putting this string on her writing board Sarah would be given the key to the padlock of the chain-link style door to her home cage, she would insert the key in the padlock, turn the key, and remove the padlock and leave with her hand in the hand of the trainer and Gussie holding Sarah's other hand and that of another trainer. There were always two trainers to assist when Sarah and Gussie got a “beach pass.” There was another door to pass through to exit their home cage facility, and then an elevator ride down to the ground level. Students were about, as were faculty, riding the elevator and walking the corridors, and here were Sarah and Gussie, unfazed, like they totally belonged. Sarah and Gussie did not wear collars, were never on a leash, and were not carried—treated just like fellow students as they came and went. To get to the beach area on campus, one had to drive through Isla Vista, the residential community adjacent to campus with all the student apartments, sororities, and fraternities. This was literally, a trip! I'd be driving my 1953 Dodge pick-up truck, Gussie in the middle, with Sarah sitting on the lap of the second assistant looking out the windows from the passenger side. Once in a while my surfboard would be hanging over the tailgate. Did we ever get the stares! That's an understatement. Interestingly, on all our outings with Sarah and Gus, we never encountered a sign of aggression toward other students or faculty walking the corridors, in the elevator, or outside. This passivity is likely due, in part, to their age, as they had not yet reached puberty. It might also have been due to their excitement to explore—never mind the human passers-by. Although we always had Sarah and Gus hand-in-hand, it never entered our minds that one could attack a passer-by; they never did.

I do not remember Premack going to the beach with us, but I'm sure he came once in a while, taking two vehicles. Such trust he had in his assistants. Once we drove out on the beach and parked, we all packed out and Gussie and Sarah would just run about on all fours, knuckle walking, as the say. Neither ever touched the water, ever. But there was plenty of sand and tide-water grasses, and no people. The beach that was part of campus was not like Coney Island on the east coast. It was generally deserted but for some wandering large dogs. I remember that on campus a lot of students had dogs, big ones, like German Shepherds, and they'd accompany their owner–students around campus. Dogs, not wild dogs, but dogs free to roam the beach and adjacent Isla Vista where students lived, would somehow gather and run in small and large packs at the empty beach, packs with as many as 15 dogs. As they'd see Sarah and Gussie somewhat near, the dogs would first run toward them. As the dogs drew closer they'd slow and finally stop. Sarah would fearlessly run toward them until they beat a fast retreat. She was incredibly fast on all fours—Gussie would be galloping just as fast, but always behind Sarah. Then Sarah would stop, stand upright, and extend her hair as would a cat to appear larger, and then she'd wave her arms in the air to appear even bigger, sometimes thumping her chest, and always ferociously barking and hooting. The dogs always made a hasty retreat, remaining at least 25 yards or more away thereafter. Dogs were at the beach on about 75% of our outings. Premack and Premack (1983, p. 6) wrote “The gallop of the chimpanzee is astounding … (they can) gallop on all fours like a demon.”

The trouble with our beach trips was not the dogs. Rather, if Mary was not along, Sarah could be very stubborn and not “mind” the other assistants. Sarah would always defer to Mary Morgan. Mary had been with Sarah at least a year before I came aboard, and Mary was clearly Sarah's favorite. Mary was the Alpha primate. With me and the other assistants (Randy Funk and Richard Sanders), Sarah could be short-tempered, and sometimes bite. “Bites are reminders that chimpanzees are not domestic animals, no matter how tame they appear. They are wild animals, able to injure even those they like most” (Premack & Premack, 1983, p. 11). Sarah had been raised with little discipline and had a mind of her own which she often asserted (Premack, 1976, p. 27). For example, when it was time to leave the beach, Mary could easily herd the chimps back into my truck. But Mary was not always present to entice Sarah to return to the truck. Without Mary, we had to wait until it got dark before we could round up Sarah (and hence Gussie, who did whatever Sarah did) as Sarah was afraid of the dark. Needless to say this state of affairs was rather inconvenient, especially when one of the trainers had to be someplace else, like class. Eventually we learned to make our beach trips about 30 min before sunset so we could come and go within an hour's time.

Sarah's fear of darkness came in handy a few times when she would escape her home cage. Sarah was strong, and as she gained sexual maturity, she became even stronger—and bigger. I do not know just how I found out, as we didn't have cell phones at the time, but I joined Premack who was on the third floor telling all faculty to shut off the lights to their labs and offices, while he managed to get the hallway ceiling lights turned off. Michael Gazzaniga's lab was just down the hall, where he was doing split-brain research with monkeys. Sarah and Gussie were roaming the ceiling and corridors! With all the lights shut off except the light in the doorway of Sarah and Gussie's home cage, the chimps came home. Sarah had unscrewed the bolts in the top of her home cage so she and Gussie could peal back the chain-link fencing and escape. They then were able to get into the hallway by climbing into the overhead ceiling area—the typical false ceiling that masks wiring and vents above. Needless to say, the chimp escape could have caused considerable havoc, but it didn't. Someone came in to patch up the home cage, perhaps me, I do not recall. I do recall entering the home cage soon afterward with my automobile wrenches and socket set and tightening all the nuts and bolts, securing the fencing as tight as I possibly could. A few months afterward, lo and behold, Sarah and Gussie made another escape. The same procedure of turning off all the lights on the floor but the one in their home cage worked again to entice Sarah and Gussie's return, without any damage to another lab. Regardless of their shenanigans, Sarah and Gussie were never hit, slapped, or in any way physically punished. Nevertheless, after this second escape Premack had all the nuts and bolts securing the cage fence welded to prevent unscrewing. I can just imagine, Sarah, hanging around her home cage, little by little, slowly but surely, unscrewing nuts and bolts! One after another, and finally, bingo—escape and explore!

At some point, probably in early 1969, the new seven- or eight-story biology building was completed next to the psychology building and new and bigger quarters were made for Sarah on the top floor. Gussie stayed behind in her old home cage. Sarah adjusted well to her new apartment, and the trainers worked more often with her to help minimize the effect of the separation from Gussie. Training sessions went forward smoothly thereafter, without Gussie's disruptive influence. It was a lot safer to be inside the new cage with Sarah without Gussie present. Here, I could enter with paint, paper, and paint brushes—and plastic words—to teach Sarah the names of the colors (yellow), (green), (blue), and (red) through a “let's paint” communication and play routine, where she'd first ask for the paintbrush with her lexicon of words, then the paint color, and then she'd paint. I still have a few examples of her artwork mounted on the wall of my office. It was not but a couple of weeks in the biology building that I got a weekend phone call informing me that Sarah had escaped. She was roaming the floor and there were large built-in aquariums nearby. Premack was there and we herded Sarah back—again with the lights out in all but Sarah's new apartment. The next work day the welder came!

Not long after moving to the biology building I graduated from UCSB and moved to Los Angeles to begin graduate school at UCLA in the fall of 1969. After almost 2 years of language training and almost daily interactions, Sarah and I parted company. I have no recollection of my “last thoughts” upon departure, but likely any memories where overshadowed by the excitement of traveling south to UCLA. The Premacks left Santa Barbara in 1975 and moved to Pennsylvania where Premack took a position at the University of Pennsylvania. Sarah and a new chimpanzee I had never met, Peony, accompanied them. Gussie was relocated to the University of Oklahoma. There, sadly, she accidentally drowned (Premack, 1976, p. 22). In 1973, after my doctoral work at UCLA, I joined a new academic branch at The University of Texas, The University of Texas of the Permian Basin, where I remain today as Professor of Psychology.

In my classroom lectures over the years, especially in introductory psychology and principles of learning courses, I would often recount stories of my 20 months with Sarah. Then, in 2003, a colleague and I assisted in developing an online introductory psychology course, and included a section on language research using nonhuman primates, similar to most introductory psychology texts. Within this section I used examples from my personal experience when teaching Sarah while working in Premack's laboratory. This online introductory course could be transferred from one instructor to another without modification and was often shifted about between faculty to teach. My coauthor, Linda Montgomery, instructed the online introductory course in spring 2016 and visited me one day in February and asked “Are you the ‘Jim’ in the story about teaching Sarah?” I said “Yes,” and she expressed considerable interest. Questions were asked about Sarah and her personal characteristics, language training, the beach experience as described in the online course, and other interesting adventures. Linda returned the following week stating she had found Sarah through an article in the New York Times (Anonymous, 2011) and suggested we visit Sarah. Sarah was living at Chimp Haven, The National Chimpanzee Sanctuary, located in Keithville, Louisiana, about 25 miles south of Shreveport. Linda also found that Sarah had her own listing in Wikipedia: ( https://en.wikipedia.org/wiki/Sarah_chimpanzee ). Having our curiosity primed, more investigation revealed that in 1987 Premack transferred Sarah to the Ohio State University (OSU) Chimpanzee Center under the direction of Sarah Boysen. She was working with several chimpanzees exploring their cognitive reasoning abilities (i.e., Boysen & Hallberg, 2000). Citing lack of funding, OSU closed the Chimpanzee Center in 2006 over the strong objections of Boysen and considerable litigation followed. As a consequence of the closure, Sarah was relocated to a primate sanctuary in San Antonio, Texas, called Primarily Primates. Within the year, Sarah was relocated again—to her present retirement home at Chimp Haven at the approximate age of 42 years.

We wrote an e-mail letter in April 2016 to the President and CEO of Chimp Haven, Cathy Spraetz, introducing ourselves and my history with Sarah at UCSB. We included our academic resumes and asked if we could visit Sarah and perhaps conduct one of the old matching-to-sample procedures to see if Sarah remembered any of her old plastic words. Sarah had stopped participating in the language study when she was about 10-years-old (Premack, 1976, p. 104), around 1971. Thus, about 45 years had elapsed since Sarah had been exposed to her language system and lexicon. We were interested in whether Sarah would remember me, the communication procedure, and some of her words after this 45 year hiatus.

Cathy replied the next day saying Chimp Haven would be delighted to host us some day. She informed us that they had a “no touch” policy and we would have to remain at least 6 feet away while we visited Sarah in her outdoor yard behind a barrier. She said there would be a few hoops to jump through to get any memory for words procedure approved, and that I would need to work with their animal behaviorist regarding any memory tasks, because we needed to keep our distance. We were excited and planned on making our trip to Chimp Haven after the spring semester, in June. I was going to make reproductions of her old plastic words, and we were going to design a battery of tests to see if Sarah remembered something of her old language days. However, our June trip was abruptly moved forward with the arrival of an April 22 e-mail from Cathy saying Sarah's health was failing—she had just been diagnosed with chronic renal failure. Cathy urged us to come right away since she couldn't guarantee Sarah would last; “these might be the end days for her” she wrote. We agreed to meet at Chimp Haven the following Tuesday morning. Linda and I drove separately to Shreveport on Monday, agreeing to meet in the hotel lobby at 7:30 a.m. the next morning.

Before heading to Shreveport I gathered supplies to make plastic words, not out of surfboard resin as I had planned, but out of poster board the thickness of Sarah's old words. I took a bunch of Sharpie colored pens, an X-Acto knife, white glue, and string to make a necklace with my name “Jim” in the shape of “J” hanging as a pendant. Arriving in Shreveport in the evening I stopped at a grocery store to get some fruit and chocolate drops. At the hotel I cut out the shapes of three plastic words that I remembered: (grape), (banana), and (apple) and colored them their proper color. I had to look at the colored pictures in the Premack and Premack (1972) article to see the shapes and colors of some words for edibles I had forgotten, and I picked (chocolate) and (apricot) and cut and colored them properly. So I had five sort-of-plastic nouns to work with, three of which I had remembered from years past (60% recall!). I remembered more of Sarah's words than these three, but those words were (give), (insert), (correct), (incorrect), (Sarah), and (Mary), but their use with Sarah was beyond what I imagined we could do on the fly, procedure-wise. I had only poster-board words, no magnetic writing board to work with, no platform to set plastic words on, much less the ability work hand-in-hand with Sarah. We really had no clue of what to expect in terms of a testing environment.

With the poster board I made a cookie sheet size (13.5 in. × 11 in.) hand-held tray and marked where three words were to go in front, 3.5 in. apart in a row, and where the edible was to go in the rear, 12 in. behind the words. Someone from Chimp Haven, who could be physically close to Sarah, would then hold the tray in front of Sarah with the words closest and the edible behind. With the five words, 15 semi-random trials were generated mixing three words per trial and positions such that each word “matched” the edible available three times out of the 15 trials. Sarah's task was to select the word that matched the edible. If Sarah picked correctly, the staff person would pick up the word and put it beside the edible, and immediately Sarah would be given the edible. If Sarah was incorrect, the word was to be handed to Jim and he put it out of sight; now Sarah could choose between the two remaining words. If Sarah was correct, she received the edible, and if she was wrong, again the incorrect word was removed and she had to merely touch the single word remaining to receive the edible. The night before, we didn't even know whether we could perform this make-shift procedure or not without it being preapproved. In addition, we didn't know whether Sarah would even appear and approach us, much less be capable of doing anything, given her health. We were also afraid it might rain, as rain was forecast in the morning.

The next morning we drove to Chimp Haven and met Cathy—and it was not raining! Cathy met us and was exceptionally gracious and resourceful throughout our visit. We were introduced to one of the full-time veterinarians, Dr. Corrine Brown, who reported that although Sarah was alert, she had lost weight, was not “shifting” (unwilling to move), and was not interested in interacting. Dr. Brown told us that although chimps in Sarah's state have been known to rally, one can never be sure. Cathy then introduced us to Amy Fultz, the animal behaviorist who would be working with Sarah and me that morning. Amy was the cofounder of Chimp Haven and presently Director of Behavior, Education, and Research. She has worked with chimpanzees since 1986 and has vast knowledge of chimpanzee behavior, and she had known Sarah since Sarah arrived in Chimp Haven. It was Amy who would assist in conducting our matching-to-sample procedure with the words and edibles. Linda and I first accompanied Cathy to an area where one family of about 25 chimpanzees were enabled to roam freely in a five acre area filled with bananas and other fruits on the ground and 100-foot pine trees to climb. There was a pond separating us from the chimpanzees, and walls about 20–25 feet high surrounding the perimeter. During our viewing time, Amy was with Sarah to see if she could encourage Sarah to leave her nest and come to the large yard area to eventually meet me. The policy at Chimp Haven prohibits “forcing” the chimpanzees to participate in any type of optional activities; and Sarah had the “choice” whether or not to participate in our study. If Sarah chose not to approach us there was absolutely nothing we would be able to do.

We next traveled to Sarah's “home” area; she lived as the oldest in a family of about 12 chimpanzees. There was Sarah, sitting alone in the center of her yard on a platform. Amy had enticed Sarah to leave her nest located in a room off the yard. I could see Sarah though about a 3 foot × 16 foot window-like opening in the wall. There was no glass in this window. Instead, there was a thick screen of wire mesh material, with about 1.5 in. square openings in the horizontal/vertical wire. I walked alone to the window as close as I was allowed (6 feet away). Amy and Linda stayed in the rear, each about 15 feet away. Cathy was at another window keeping Henry, the alpha male of the family, entertained so he would not interfere with our visit with Sarah. I started speaking to Sarah. I was wearing my “J-necklace,” white t-shirt, a blue-plaid Pendleton wool shirt, blue Sperry canvas yacht shoes, and light colored Levi pants. This was my general “surfer” attire back at UCSB.

While I walked to the window Sarah seemed to notice me and made several vocalizations. I then stood talking to Sarah, dressed in the attire of my young adulthood, saying I was Jim, from old Santa Barbara days, and continued talking about trivia from the past. Sarah had made eye contact with me from the beginning. Keeping her eyes on me, she slowly came down from the platform and walked over to me, and resting on a platform on the other side of the window. Although much of my appearance had changed with the years, I still had my old voice, my old clothes, and my mustache (though gray). During her deliberate but slow walk over to me she made what Cathy and Amy referred to as “pleasure pants.” Pleasure pants indicate that an individual is welcomed. Cathy and Amy both reported that by Sarah's behavior she certainly recognized me. Sarah was unhurried, very attentive, and what I'd call “sweet.” Not unlike seeing a little old person in an assisted living home, sitting alone in a chair and attentively watching passersby, and nodding to one she recognized to join her in a little conversation.

After about 20–30 min of reunion time, Amy came forward next to the window. She was wearing surgical gloves and a plastic mask covering her face, as was policy—just in case a chimp threw something. With me as the assistant, Amy and I began the first of 30 matching-to-sample trials at the window with Sarah. Indeed, it was a privilege to work with someone with as much knowledge and experience as Amy. I had generated 15 semi-randomized trials, and we were able to go through this sequence twice, as Sarah was very attentive. With three “sort-of-plastic words” on the tray and an edible behind, Amy held the tray forward next to the wire mesh. Sarah was able to poke one finger though the opening, her index finger of her right hand. It appeared Sarah clearly remembered basics of the procedure even though she was prevented from picking up the words. She saw the edible, then poked her finger through the mesh to the “word” she selected by touching it. It was not possible to pick up one of the words, only touch. And so she did—select, touch, and eat! Amy and I did our best not to provide gestures or verbal cues that might guide Sarah's selection. But in her selection process, Sarah was not looking at either of us, she was looking at the words and edible on the tray in front of her. After each trial I would reset the words and the edible in anticipation of the next trial. When Sarah had finished eating, we began another trial by placing the tray in front of the wire mesh. At the end of over 2 hr with Sarah we terminated the session. Although Linda and I were tired of standing; Sarah could have stayed on.

Interestingly, after the eighth trial, a long golf cart people-transporter rolled up about 20 feet away carrying about 15 children. Chimp Haven is only open to visitors during “Chimpanzee Discovery Days,” about three times a year. These children were visiting as part of the “Classrooms that Care” program. Apparently Sarah was not happy to have these observers, even at a distance. Without a gesture, Sarah quietly and slowly left her window platform and lumbered back to the platform in the middle of the play area and sat down. Once the cart moved on, Sarah returned to the window platform and we continued the trials. Remember, Sarah is an aging chimpanzee who had not been feeling well, but did come back to the window, walking a bit slowly and touching the enclosure side with her hand as she walked, as if for balance. Amy and Cathy saw Sarah's return as another indicator of her memory for me, where she felt safety and pleasure in interacting with us again. Of course, Sarah was also enjoying some of her favorite edibles!

There were clearly three measures of Sarah's memory, which she passed with flying colors. First, the experts, Amy and Cathy reported that Sarah remembered Jim with her pleasure pants and other “approach” behaviors. Second, after the golf cart people transporter left, Sarah returned to work on the trials. And third, Sarah clearly aced the mechanics of our matching-to-sample procedure. She knew exactly what to do, in spite of the limitation of being unable to pick up the words. We left Chimp Haven thrilled with Sarah's ability to remember Jim, and just as important, remembering the procedure. First and foremost though, we were so happy that Sarah appeared to be doing okay, and that it hadn't rained, and that Sarah had chosen to participate in the study even though she may not have been in the best health. We couldn't wait to return to the university and examine the results of Sarah's 30 trials. On first blush it appeared that Sarah had correctly selected words better than chance, but we didn't know for sure until the results were analyzed.

To begin our analysis of the data, we first wanted to know whether there was any left-middle-right preference as Sarah went about selecting one of the three words presented. She picked the word on her right 11 times, in the middle 10 times, and on her left nine times. These left-middle-right differences were clearly not statistically different. With no directional preference evident, we then examined the correctness of her choices. With three words available to select from, Sarah chose correctly 11 out of the 30 trials, or 37%, which was not different from chance at 33%. There were 19 trials where Sarah chose incorrectly the first time, leaving two remaining words to choose from. On these trials, where one would expect her to be correct 50% of the time, she was actually correct 13 times (65%). However, this difference was not statistically better than chance, χ²(1) = 2.13, N.S.

We next examined whether there was any practice effect, such that Sarah may have performed better during the second half of the 30 trials. With three words available, in Trials 1–15, Sarah was correct five times (which is exactly the chance level of 33%); in Trials 16–30 Sarah got six correct (40% correct). These differences in performance showed no improvement over trials. We looked similarly at the 19 trials were Sarah was wrong with her first choice, and was left to select between two remaining words. During Trials 1–15, Sarah got 7 of 10 trials correct (70%), and in Trials 16–30 she got 6 of 9 correct (67%). Although it appeared she did better than the chance level of 50%, her performance was not statistically better than chance.

Finally, we examined Sarah's correct and incorrect rate with trials where the word grape was displayed. One will recall that Sarah preferred grapes in the old days, and Amy confirmed that Sarah still preferred grapes today. On the six of 30 trials where an actual grape was the edible, Sarah chose correctly four times (67%), once over Trials 1–15, and all three times over Trials 16–30 (100%). Due to the small numbers, however, no statistical analysis using chi square was appropriate. Looking at Sarah's errors, we found that across all 30 trials, of Sarah's 19 initial errors, on eight of these error trials the word (grape) was displayed with an edible other than grape. On these eight trials, Sarah picked the word (grape) five times (62%). The chance probability to compare this rate to is .21 (21%). However, Sarah's errors were not significantly different from chance to conclude that she was trying to tell us something, like she'd prefer a grape to the edible being offered, χ²(1) = 2.72, N.S.

If we had had more days, and more sessions with Sarah, one might expect some evidence of memory for some of her prior nouns. Beran, Pate, Richardson, and Rumbaugh (2000) found that Lana, the chimpanzee who had been taught a computer supported symbolic language system when she was 2-years-old, recognized five of seven “lexigrams” after a 20-year hiatus. Of course, Lana was healthy, about 30 years younger than Sarah at retesting, and was working in an environment similar to her original testing environment.

Although Sarah revealed no recall for five nouns previously in her vocabulary, for sake of comparison, recall that Jim only remembered three of the five words Sarah was tested with in June. On the other hand, it's clear that Sarah wanted to be part of the procedure, the “game,” like persons gathering for a weekly game of bridge. Even though she was ill, she seemed to be saying, “I know you, Jim, and I'd like to hang out with you for a while doing what we used to do.” Sarah remembered Jim, and that she remembered the basic mechanics of the matching-to-sample procedure is remarkable. “Of all the prerequisites for language, none is more vital, though more easily overlooked, than memory … For it is not the objects, the actions, or the properties that we perceive in the real world that are associated with words, but the representation in memory that makes language possible” (Premack & Premack, 1983, p.113).

After returning home, we each made an unsolicited donation to Chimp Haven, as Cathy and Amy had been most gracious. We extend our thanks. For Sarah, who loved to wrap in a beach towel or blanket, we sent a blue beach towel as a gift with the UCSB logo inscribed in large yellow letters. We wish the best for Sarah in her retirement, and her continued rally and better health.

The reader interested in Premack's further ideas on reasoning and conceptual foundations in primates using a language medium, and the debate whether chimpanzees are using language as you and I understand it, is encouraged to read Premack's 1986 work. It was not only a pleasure to have worked with Sarah, but an educational gold mine to have worked with Premack as an undergraduate. As Gazzaniga (2012, p. 107) succinctly said before Premack's death in 2015 at the age of 89 years, “It is hard to think of a more important living psychologist than David Premack.”