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**