This study was approved by the Ethics and Animal Welfare Committee of the University of Veterinary Medicine Vienna in accordance with good scientific practice guidelines and national legislation. The experiment was purely appetitive and strictly non-invasive and was therefore classified as a non-animal experiment in accordance with the Austrian Animal Experiments Act (TVG 2012). The part of the experiment conducted in Indonesia was approved by the Ministry of Research, Technology and Higher Education (RISTEK) based on a meeting by the Foreign Researcher Permit Coordinating Team (10/TKPIPA/E5/Dit.KI/X/2016) who granted the permits to conduct this research to M.O. (410/SIP/FRP/E5/Dit.KI/XII/2016) and B.M. (411/SIP/FRP/ E5/Dit.KI/XII/2016).
1. Preconditions/prerequisites
Figure 1: Diagram of a basic three-sided box. Please click here to view a larger version of this figure.
Figure 2: Tasks of the Innovation Arena with a corresponding description of the motoric action required for solving ( = reward; red arrows indicate directions of actions required to solve tasks; yellow arrows indicate reward trajectories). Tasks are arranged according to their mean difficulty (left to right, top to bottom). Previously published in32. Please click here to view a larger version of this figure.
2. Preparations
Figure 3: The Innovation Arena. Tasks arranged in a semi-circle; the positions of the 20 tasks are exchangeable. A proximity grid (20 cm in front of each box) is marked in black. Please click here to view a larger version of this figure.
3. Habituation
NOTE: The purpose of habituation is to reduce influences of neophobic reactions toward the arena. Ensure a minimum habituation level for all subjects through a habituation procedure that requires each individual to reach two criteria.
4. Testing
5. Motivation protocol
NOTE: As described above (step 4.9), a motivational protocol can be implemented if an individual does not interact with any task within the first 3 min of a session.
6. Analysis
Nineteen subjects were tested using the Innovation Arena: 11 long-term and 8 short-term captive cockatoos (Figure 4).
Figure 4: An overview of the number of tasks solved per session for each individual. a) Field group, b) Lab group. Red lines = female; blue lines = male. Subjects receiving the motivational protocol due to their reluctancy to interact with the apparatus were classified as not motivated and depicted with a gray background. Previously published in Supplementary Information of32. Please click here to view a larger version of this figure.
The Principal Component Analysis resulted in two components having Eigenvalues above Kaiser´s criterion38 (see Table 2 for PCA output). PC1 loaded on frequency of contacts with tasks, time spent in proximity (i.e., within the grid) of the tasks, and the number of tasks touched. PC2 was positively affected by the number of contacts with already solved tasks and negatively with the number of tasks touched, not solved. Such task-directed behaviors are frequently used for measuring motivation (see12 for a review). Therefore, we used PC1 and PC2 as quantitative measures for motivation to interact with the apparatus in our model. Together they explained 76.7% of the variance in apparatus-directed behaviors and both, as well as session, significantly influenced the probability to solve tasks (PC1: estimate = 2.713, SE ± 0.588, χ2 = 28.64, p < 0.001; PC2: estimate = 0.906, SE ± 0.315, χ2 = 9.106, p = 0.003; session: estimate = 1.719, SE ± 0.526, χ2 = 6.303, p = 0.001; see Figure 5; see Table 4).
Figure 5: Influence of control predictors on the probability to solve: (a) PC1, (b) PC2, (c) Session. Points show observed data, area of points indicates the number of observations for each data point, dashed lines show fitted values of model and areas symbolize confidence intervals of model. Previously published in32. Please click here to view a larger version of this figure.
Six out of the 19 subjects received the motivational protocol during the experiment (Lab: 1 out of 11; Field: 5 out of 8). PC1 of these birds, which we categorized as not motivated, ranged between -2.934 to -2.2, while positive values were found for all other motivated individuals (Table 3).
With the presented method we found no difference of group on the probability to solve the 20 technical problem-solving tasks of the Innovation Arena (estimate = −0.089, SE ± 1.012, χ2 = 0.005, p = 0.945; Figure 5; see Table 4 for fixed effects estimates; all birds included).
A post-hoc comparison of the model with one including an interaction term of group with session (estimate = 2.924, SE ± 0.854, χ2 = 14.461, p < 0.001) suggests lower probability to solve in the field group in earlier sessions but not in the later. This difference in earlier sessions might be due to the high number of less/not motivated birds in group field (individuals for which testing stopped due to the rule of not solving any task in 10 consecutive sessions received between 10 and 13 sessions).
Further, we found no difference between the groups regarding the overall difficulty of tasks (comparison of full model with all birds included, with a reduced model lacking random slope of Group within Task: χ2 = 7.589, df = 5, p = 0.18). However, visual comparisons of birds that never required a motivational trial, hint to some differences in ability for single individual tasks (see, e.g., the Button task in Figure 6).
Figure 6: Observed data of motivated subjects and fitted values of model per task and group: Boxplots show the proportion of successes per task for both groups (green = Field; orange = Lab). Bold horizontal lines indicate median values, boxes span from the first to third quartiles for birds. Boxplots illustrate data from motivated birds only (to improve visual clarity). Individual observations are depicted by points (larger area indicates more observations per data point). Red horizontal lines show fitted values. Fitted values originate from the whole data set. Included are illustrations of Bite (bottom left), Button (top middle) and Seesaw (top right) tasks. Previously published in32. Please click here to view a larger version of this figure.
These results demonstrate the feasibility of the methodology for comparative research even if the animals have different experiences and ecological circumstances. A comparison of innovative problem-solving abilities using only a single task, such as the Button task, might have yielded a false conclusion that long-term captive birds are better problem-solvers. This difference could be explained by the lab population’s experience with stick insertion experiments while the motor action might not be as ecologically relevant for wild populations. Such differences could potentially be more pronounced when different species are compared (see19). We were further able to test how motivation affects problem-solving ability, while at the same time comparing the results of the two groups while controlling for motivation.
The 20 technical problems of the Innovation Arena can therefore be used to detect group differences on particular tasks, but also to estimate the overall innovative ability of groups. In the case of the Goffin`s cockatoo, both groups can, i.e., have the ability to, retrieve many rewards, if they want to, i.e., are motivated to interact with the apparatus.
Table 1: Protocol for coding behaviors: Detailed description of coded behavioral variables. Previously published in32. Please click here to download this Table.
Table 2: Principal component output: Factor loadings above 0.40 are printed in bold. Previously published in32. Please click here to download this Table.
Table 3: Details on subjects and values of task-directed behaviors and principal components: Superscripts if measure loads go above 0.40 per PC. Previously published in32. Please click here to download this Table.
Table 4: Fixed effects results of the model for probability to solve. Previously published in32. Please click here to download this Table.
Supplementary File: Technical drawing of the Innovation Arena (InnovationArena.3dm). Dimensions might deviate slightly. Can be loaded, e.g., in 3dviewer.net, which is a free and open source 3D model viewer39. Please click here to download this File.
wooden platform | Dimensions: woodensemicircle, radius approx. 1.5m | ||
FIXATION SYSTEM | |||
5 x metal nut | Dimensions: M8 | ||
5 x rod | (possibly with U-profile) | ||
5 x threaded rod | Dimensions: M8; length: 25cm | ||
5 x wing nut | Dimensions: M8 | ||
PUZZLE BOXES WITHOUT FUNCTION PARTS | |||
20 x acrylic glass back | Dimensions: 17cm x 17.5cm x 0.5cm | ||
20 x acrylic glass base | 4 holes for screws roughly; 2cm from each side Dimensions: trapezoid : 17.5cm (back) x 15cm (front) x 15cm (sides); 1cm thick |
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20 x acrylic glass front | acrylic glass fronts need to be cut differently for each puzzle box (see drawing) Dimensions: 17cm x 15cm x 0.5cm |
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20 x acrylic glass lid | cut out 0.5cm at the edges for better fit Dimensions: trapezoid shape: 18.5cm x 16cm x 16cm x 1cm (thick) |
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40 x acrylic glass side | Dimensions: 17cm x 16cm x 0.5cm | ||
80 x small screw | to attach bases to the platform (4 screws per base) | ||
PARTS FOR EACH MECHANSIM PER TASK | |||
to assemble the parts use technical drawing InnovationArena.3dm | can be loaded e.g. in 3dviewer.net, which is a free and open source 3D model viewer. github repository: https://github.com/kovacsv/Online3DViewer; please contact authors if you are in need of a different format | ||
TASK TWIST | |||
5x small nuts | to attach glass (punch holes) and acrylic glass cube to threaded rod | ||
acrylic glass | Dimensions: 2cm x 2cm x 1cm | ||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
plastic shot glass | Dimensions: height: 5cm; rim diameter: 4.5cm; base diameter: 3cm | ||
thin threaded rod | Dimensions: length: approx. 10cm | ||
TASK BUTTON | |||
2x nut | attach to rod; glue outer nut to rod Dimensions: M8 |
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acrylic glass | V-cut to facilitate sliding of rod Dimensions: 4cm x 3cm x 1cm (0.5cm V-cut in the middle ) |
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cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
threaded rod | Dimensions: M8, length: 5cm | ||
TASK SHELF | |||
acrylic glass top | Dimensions: 5cm x 4cm x 0.3cm | ||
acrylic glass lower | Dimensions: 5cm x 4cm x 1cm | ||
acrylic glass side 1 | Dimensions: 4cm x 3cm x 0.5cm | ||
acrylic glass side 2 | Dimensions: 4.5cm x 3cm x 0.5cm | ||
thin plastic bucket | on side cut off to fit Dimensions: diameter: approx. 4.5 cm; height: 1cm |
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cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
TASK SLIT | room to reach in: 2cm in height | ||
– | recommended: add small plastic barrier behind reward so it cannot be pushed further into the box | ||
TASK CLIP | |||
2x acrylic glass | Dimensions: 1cm x 1cm x 2cm | ||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
peg | Dimensions: length: approx. 6 cm | ||
thin threaded rod | Dimensions: length: approx. 6 cm | ||
TASK MILL | |||
2x arylic glass triangle | Dimensions: 10cm x 7.5cm x 7.5cm; thickness: 1cm | ||
2x plastic disc | Dimensions: diameter: 12cm | ||
4x small nut | for attachment | ||
7x acrylic glass | Dimensions: 4.5cm x 2cm, 0.5cm | ||
acrylic glass long | position the mill with longer acrylic glass touching lower half of the front (this way the mill can only turn in one direction) Dimensions: 6.5cm x 2cm, 0.5cm |
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thin threaded rod | Dimensions: length: approx. 4cm | ||
wooden cylinder | Dimensions: diameter: 2cm | ||
TASK SWISH | |||
2x acrylic glass | Dimensions: 2cm x 1cm x 1cm | ||
4x small nut | for attachment | ||
acrylic glass | Dimensions: 10cm x 2cm x 1cm | ||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
thin threaded rod | Dimensions: length: approx. 7cm | ||
wooden cylinder | Dimensions: diameter: 2cm, cut-off slantwise; longest part: 7cm, shortest part: 5cm | ||
TASK SHOVEL | |||
acrylic glass | Dimensions: 20cm x 2cm x 1cm | ||
acrylic glass | Dimensions: 7.5cm x 2cm x 1cm | ||
acrylic glass | Dimensions: 5cm x 1cm x 1cm | ||
small hinge | |||
TASK SWING | |||
4x nut | Dimensions: M8 | ||
acrylic glass | Dimensions: 7.5cm x 5cm x 1cm | ||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
cord strings | Dimensions: 2x approx. 11cm | ||
thin bent plastic | bucket to hold reward; positioned on slant | ||
threaded rod | Dimensions: M8; length: 7cm | ||
TASK SEESAW | |||
2x acrylic glass | Dimensions: 10cm x 1.5cm x 0.5cm | ||
2x acrylic glass | Dimensions: 4cm x 1.5cm x 0.5cm | ||
acrylic glass | Dimensions: 10cm x 3cm x 0.5cm | ||
acrylic glass | Dimensions: 4cm x 1.5cm x 1cm | ||
small hinge | |||
TASK PLANK | |||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
thin tin | bent approx. 1cm inside box Dimensions: 6.5cm x 3cm |
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TASK CUP | |||
plastic shot glass | Dimensions: height: 5cm; rim diameter: 4.5; base diameter: 3cm | ||
TASK FLIP-BOX | |||
2x acrylic glass triangle | Dimensions: 7cm x 5cm x 5cm; thickness: 0.5cm | ||
2x acrylic glass | Dimensions: 4.5cm x 5cm x 0.5cm | ||
2x acrylic glass | Dimensions: 7cm x 1cm x 1cm | ||
small hinge | |||
TASK SLIDE | |||
4x acrylic glass | Dimensions: 15cm x 1cm x 0.5cm | ||
acrylic glass door | Dimensions: 6cm x 6cm x 0.5cm | ||
TASK DJ | |||
2x small nut | for attachment | ||
acrylic glass | same as box bases Dimensions: trapezoid : 17.5cm (back) x 15cm (front) x 15cm (sides); 1cm thick |
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plastic disc | Dimensions: diameter 12cm | ||
thin threaded rod | Dimensions: length: approx. 3cm | ||
TASK WIRE | |||
acrylic glass | Dimensions: 9.5cm x 9.5cm x 0.5cm | ||
acrylic glass | Dimensions: 12cm x 2cm x 1cm | ||
2x small hinge | |||
wire from a paperclip | |||
TASK TWIG | |||
2x small hinge | |||
acrylic glass | Dimensions: 5cm x 1cm | ||
cardboard slant | Dimensions: trapezoid: 17.5cm (back) x 15cm (front) x 17cm (sides) | ||
white cardboard | Dimensions: 13cm x 4cm | ||
Y-shaped twig | Dimensions: length: approx. 14cm | ||
TASK COVER | |||
acrylic glass | same as box bases Dimensions: trapezoid : 17.5cm (back) x 15cm (front) x 15cm (sides); 1cm thick |
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thin plastic | Dimensions: diameter: 5cm | ||
TASK BITE | recommended: put tape on sides of platform the keep reward from falling off | ||
2-3 paper clips | |||
2x cutouts from clipboard | Dimensions: 10cm x 3cm | ||
acrylic glass | hole in middle Dimensions: 5cm x 3cm x 1cm |
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toilet paper | |||
TASK DRAWER | |||
2x acrylic glass | Dimensions: 5cm x 2.5cm x 0.5cm | ||
2x acrylic glass | Dimensions: 4cm x 3cm x 1cm | ||
acrylic glass | hole approx. 2 cm from front Dimensions: 5cm x 5cm x 1cm |
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OTHER MATERIAL | |||
wide-angle videocamera |
Problem-solving tasks are commonly used to investigate technical, innovative behavior but a comparison of this ability across a broad range of species is a challenging undertaking. Specific predispositions, such as the morphological toolkit of a species or exploration techniques, can substantially influence performance in such tasks, which makes direct comparisons difficult. The method presented here was developed to be more robust with regard to such species-specific differences: the Innovation Arena presents 20 different problem-solving tasks. All tasks are presented simultaneously. Subjects are confronted with the apparatus repeatedly, which allows a measurement of the emergence of innovations over time – an important next step for investigating how animals can adapt to changing environmental conditions through innovative behavior.
Each individual was tested with the apparatus until it ceased to discover solutions. After testing was concluded, we analyzed the video recordings and coded successful retrieval of rewards and multiple apparatus-directed behaviors. The latter were analyzed using a Principal Component Analysis and the resulting components were then included in a Generalized Linear Mixed Model together with session number and the group comparison of interest to predict the probability of success.
We used this approach in a first study to target the question of whether long-term captivity influences the problem-solving ability of a parrot species known for its innovative behavior: the Goffin´s cockatoo. We found an effect in degree of motivation but no difference in the problem-solving ability between short- and long-term captive groups.
Problem-solving tasks are commonly used to investigate technical, innovative behavior but a comparison of this ability across a broad range of species is a challenging undertaking. Specific predispositions, such as the morphological toolkit of a species or exploration techniques, can substantially influence performance in such tasks, which makes direct comparisons difficult. The method presented here was developed to be more robust with regard to such species-specific differences: the Innovation Arena presents 20 different problem-solving tasks. All tasks are presented simultaneously. Subjects are confronted with the apparatus repeatedly, which allows a measurement of the emergence of innovations over time – an important next step for investigating how animals can adapt to changing environmental conditions through innovative behavior.
Each individual was tested with the apparatus until it ceased to discover solutions. After testing was concluded, we analyzed the video recordings and coded successful retrieval of rewards and multiple apparatus-directed behaviors. The latter were analyzed using a Principal Component Analysis and the resulting components were then included in a Generalized Linear Mixed Model together with session number and the group comparison of interest to predict the probability of success.
We used this approach in a first study to target the question of whether long-term captivity influences the problem-solving ability of a parrot species known for its innovative behavior: the Goffin´s cockatoo. We found an effect in degree of motivation but no difference in the problem-solving ability between short- and long-term captive groups.
Problem-solving tasks are commonly used to investigate technical, innovative behavior but a comparison of this ability across a broad range of species is a challenging undertaking. Specific predispositions, such as the morphological toolkit of a species or exploration techniques, can substantially influence performance in such tasks, which makes direct comparisons difficult. The method presented here was developed to be more robust with regard to such species-specific differences: the Innovation Arena presents 20 different problem-solving tasks. All tasks are presented simultaneously. Subjects are confronted with the apparatus repeatedly, which allows a measurement of the emergence of innovations over time – an important next step for investigating how animals can adapt to changing environmental conditions through innovative behavior.
Each individual was tested with the apparatus until it ceased to discover solutions. After testing was concluded, we analyzed the video recordings and coded successful retrieval of rewards and multiple apparatus-directed behaviors. The latter were analyzed using a Principal Component Analysis and the resulting components were then included in a Generalized Linear Mixed Model together with session number and the group comparison of interest to predict the probability of success.
We used this approach in a first study to target the question of whether long-term captivity influences the problem-solving ability of a parrot species known for its innovative behavior: the Goffin´s cockatoo. We found an effect in degree of motivation but no difference in the problem-solving ability between short- and long-term captive groups.