Animal Cognition - September 2018

'''Watson, S. K., Vale, G. L., Hopper, L. M., Dean, L. G., Kendal, R. L., Price, E. E., … Whiten, A. (2018). Chimpanzees demonstrate individual differences in social information use. Animal Cognition, 21(5), 639–650. https://doi.org/10.1007/s10071-018-1198-7'''

Looking at 16 different social learning studies from over the course of 12 years on the same population of 167 chimpanzees at the National Center for Chimpanzee Care in Bastrop, TX who had participated in at least 1 experimental condition across the studies. Each individual was assigned a Social Information Score (SIS) of either 1 or 0. An SIS of 1 for if they used social information to solve an experimental task and 0 if not. Researchers used Bayesian binomial mixed effects modeling to estimate the extent to which sex, rearing history, age, experience, and pedigree/genetic heritability effected one’s use of social information. There was a sex difference in SIS (females used social information more than males) and some evidence of rearing history effecting SIS, but about half of the variance in SIS was explained by individual differences.

'''Kanizsár, O., Mongillo, P., Battaglini, L., Campana, G., Lõoke, M., & Marinelli, L. (2018). The effect of experience and of dots’ density and duration on the detection of coherent motion in dogs. Animal Cognition, 21(5), 651–660. https://doi.org/10.1007/s10071-018-1200-4'''

Dogs were given a two-alternative forced-choice discrimination task in which they were to select the choice with greater motion coherence (by touching their snout to a monitor). Dot arrays were manipulated to show varying degrees of density and duration. Dogs were retested after an interval of two months to assess wither experience with the stimuli affected individual’s threshold for detecting motion (especially considering that, when first tested, their threshold for detecting motion was higher than that previously found in humans, cats, seals, and monkeys). Performance improved with increasing density and duration (but was only hindered at a very short duration of 50ms and then leveled off after 200ms), and there was slight improvement with experience, but it did not reach significance. They conclude that dogs are efficient in local integration (due to their performance at shorter durations) but less efficient in global integration (linear increase in performance for increasing densities).

'''Sommer-Trembo, C., & Plath, M. (2018). Consistent individual differences in associative learning speed are not linked to boldness in female Atlantic mollies. Animal Cognition, 21(5), 661–670. https://doi.org/10.1007/s10071-018-1201-3'''

The fish where scored for boldness on two different experimental situations and then tested for associative learning speed in two classical conditioning tests: respond to either a yellow light or the sound of flowing water that had been associated with a piece of food. There was no correlation for boldness and learning speed, indicating that individual differences in learning are not related to a boldness as a personality trait.

'''Kano, F., Moore, R., Krupenye, C., Hirata, S., Tomonaga, M., & Call, J. (2018). Human ostensive signals do not enhance gaze following in chimpanzees, but do enhance object-oriented attention. Animal Cognition, 21(5), 715–728. https://doi.org/10.1007/s10071-018-1205-z'''

Here, the authors were interested in investigating whether great apes would follow the gaze of a human when that human had addressed them ostensively by making eye contact and saying their name. In the experimental condition, the experimenter made eye contact while saying the name of the subject and then looking at a target object. For control attention-getting conditions the experimenter either nodded, had a moving object on their face, or ate something (making eating motions) before looking at a target object. Unlike human infants or dogs, chimpanzees, orangutans, and bonobos do not require ostensive signals to follow an experimenter’s gaze to the target object. However, ostensive signals increased attention (longer looking time) to the target and distractor objects for chimps and orangs but not bonobos, suggesting they are interpreting ostensive signals as preceding information about the objects. Overall, the authors suggest that infants and dogs (domesticated species) may be better at understanding human referential signals than great apes.

See Fröhlich and van Schaik (2018) for a review article on multimodal communication in great apes and understanding the function of signals/gestures accompanying vocalizations:

'''Fröhlich, M., & van Schaik, C. P. (2018). The function of primate multimodal communication. Animal Cognition, 21(5), 619–629. https://doi.org/10.1007/s10071-018-1197-8'''