Current bio - June 2018

Already
discussed in an earlier email chain, Eckert, Rokoczy, Call, Herrmann, &
Hanus (2018) published a paper in this month’s issue of Current Bio about
chimpanzees considering humans’ psychological states when making statistical
inferences. In three experiments there were always two transparent jars: one
contained a large proportion of a favorable food to a less favorable food (i.e.
200 peanuts to 20 carrots) and the other contained a large proportion of a less
favorable food to a favorable food (200 carrots to 20 peanuts). When drawing
randomly, the chimps picked from the experimenter that had a large amount of
favorable foods more often. However, the two experimenters then began drawing
into the jars while looking and were biased in their choices – the experimenter
with the jar of mostly peanuts would always pick a carrot and vice versa. Now
the chimps chose from the experimenter that had a jar of mostly carrots but a
“preference” for peanuts. They also included a third experiment in which one
experimenter drew randomly from the highly favorable jar and one experimenter
drew with her “bias” for the highly favorable reward. Then when drawing from
jars that were equal in ratio favorable to nonfavorable, the chimps continued
to choose more often from the experimenter that was looking into the jar and
picking the favorable reward. The results are definitely interesting, but its
still up for debate as to whether this is chimps making choices based on human
psychological states or something less complex like: ‘did the human look or not’?

Article: https://www.cell.com/current-biology/fulltext/S0960-9822(18)30549-9?dgcid=raven\_jbs\_etoc\_email

Dispatch article:
https://www.cell.com/current-biology/fulltext/S0960-9822(18)30620-1?dgcid=raven\_jbs\_etoc\_email

Also, one
other paper that might be interesting to some: a recent paper by Jiang et al
provides evidence that macaque monkeys can “break the syntax” barrier – produce
spatial sequences that represent more complex grammar. Monkeys produced sequences
by pressing a touchscreen, generated according to “instructed grammars” – a
mirror grammar (ABC --> CBA) and a repeat grammar (ABC --> ABC), and they produced these in different spatial
arrays, at different sequence lengths, and on arrays at different spatial
locations. The monkeys were also able to produce not just the second half, but
the full sequence as well (ABCCBA), which demonstrates that they are producing
a complete center-embedded sequence. Finally, one monkey was trained to
complete a sequence given just one position (A --> BCCBA). The authors claim that
this study goes beyond previous studies that show sequence learning using strategies
such as chunking, algebraic patterns, and ordinality because it also includes
production of a complete sequence, generalization to novel arrays, lengths, and
locations. I’d be interested to hear what others think about this one, because
I’m still not completely sold on how this is completely indicative of complex
grammar/computational strategies rather than something more memory related,
which they mention at the end. I still think the results and are really cool
and interesting, but this is not an area I am an super well-versed in either.

Article: https://www.cell.com/current-biology/fulltext/S0960-9822(18)30519-0?dgcid=raven\_jbs\_etoc\_email

Dispatch article:
https://www.cell.com/current-biology/fulltext/S0960-9822(18)30559-1?dgcid=raven\_jbs\_etoc\_email