Designing smart tests for bird brains

bruiser.gif

Bruiser participated in my first North Island robin cognition study in 2014 and is no stranger to cognitive tests. In my latest research, carried out in 2015 and recently published in Behavioural Processes, Bruiser quickly mastered opening swivel lids to grab a snack. By contrast, those robins that had never been tested were slow to catch on.

If prior experience affects performance in a cognitive task, how can we fairly compare naïve and experienced birds? Designing tests that can give us unbiased, accurate measures of cognitive ability in the wild gets even more complicated when we start to consider other factors, such as hunger or boldness.

As it turns out,  I also found that hungry robins performed worse than their well-fed counterparts in a test of inhibitory control. These birds were more likely to keep pecking at food through a transparent barrier, rather than reaching around the barrier to retrieve it.

Lid-opening and ‘detour-reaching’ tasks are commonly used cognitive tests for birds. However, the robins’ performance reveals some pitfalls in relying on these tasks to measure individual cognitive ability. It hardly seems fair to compare a spoilt little Bruiser with a hungry bird who has never been to robin school…

Robin selfies

Over the past few weeks Latu has been hard at work documenting the caching behaviour of the youngest birds in our study population. Judging from the footage, it looks like her efforts to film cache sites haven’t gone unnoticed by all of the juveniles…

Robin selfie

Kiwi chaos!

Bullers_kiwisRobin breeding season has been in full swing for the past couple of months. Two weeks ago one of our nest cameras caught a surprising new kiwi behaviour on film.

You can check out what happened here.

Sadly, Darcy and Lizzie’s nest was destroyed by the kiwi and their 10 day old chicks were killed. This was a disaster for the robin pair (Lizzie has left Darcy as a result), but it is the first time a little spotted kiwi has ever been seen doing something like this.

This unexpected ‘dark side’ to our national icon captured quite a lot of local media attention and created some… interesting headlines:

Deadly kiwi whacks robins on her turf | National | NZ Herald News

‘Shocking’ video shows macho kiwi obliterating robins’ nest and leaving chicks for dead | ONE News Now | TVNZ

Video: Killer kiwi ravages robin’s nest | NZNews | 3 News

Rachael also spoke to Radio NZ about the ‘killer kiwi’ incident.

 

Developing IQ tests for bird brains

Imagine that you’re taking an IQ test. You’re asked questions that assess a range of cognitive domains, such as verbal comprehension, perceptual organisation, working memory, processing speed… and the list goes on. If you reckon you did well in one cognitive domain of the imaginary IQ test you just took, chances are you did pretty well in the rest of them too.

A remarkable aspect of human psychometric test batteries is that scores between tests of different cognitive domains are positively correlated. In fact, human psychometric test battery performance is underpinned by a “general factor”, called g (for general intelligence), that typically accounts for 40-50% of the variance in task performance. Evidence for human g was first reported well over a hundred years ago.

By contrast, there has been little research into whether g exists in non-human animals. In particular, we know very little about the structure of intelligence in birds. Luckily, however, wild North Island robins are very willing psychometric test subjects.

Robins participated in a test battery that used six established measures of avian cognitive performance: a motor task, colour and shape discrimination, reversal learning, spatial memory and inhibitory control. Much like human test subjects, individual robins varied greatly in their ability to solve the tasks. Analysis of their performance in the test battery revealed that birds that did well in one task were likely to do well in the other tasks.

Putting Bowie through his paces in the robin cognitive test battery. At the start and end of each session he jumped on the scales so we could keep track of his motivation.

Putting Bowie through his paces in the robin cognitive test battery. At the start and end of each session he jumped on the scales so we could keep track of his motivation levels.

Strikingly, a general cognitive factor, analogous to human g, underpinned cognitive performance and explained over 34% of variance in the robin test battery. There is still a long way to go in terms of developing a truly comprehensive test battery for birds, but this result suggests that their cognitive performance may share a similar structure with humans. The next step will be adding tests that can tap into more cognitive domains, to get a fuller picture of how these little bird brains think about the world.