Fig 1.
The neural model controlling the iCub robot in ongoing learning.
External input to each field is constantly driven by visual input, momentary body posture, and online speech recognition. Internal input to each field is a spreading activation via associative connections subject to ongoing learning and via the body posture. Note: the neural model forms the highest layer of a subsumption architecture controlling the robot, further details are in the Supplementary Information to this paper. (The individual shown in this figure has given written informed consent (as outlined in PLOS consent form) to publish this image).
Fig 2.
The timeline of an individual in Experiment 1 (no-switch condition), showing the neural activity in the Vision, Posture, and Word Fields as well as the visual input to iCub at each step.
Fig 3.
The timeline of an individual in experiment 4 (interference task), showing the neural activity in the Vision, Posture, and Word Fields as well as the visual input to iCub at each step.
Fig 4.
Timeline of experiment 6 (above) and experiment 8 (below).
Steps 1–4 expose the infant to the target and foil objects in consistent left and right locations. In step 5 the infant is told ‘this is a modi’ while the objects are out of sight (hidden in buckets) in experiment 6, or while the foil object is in the target object location and being attended in experiment 8. Steps 6 & 7 repeat the original exposure of the target and foil, and in step 8 the infant is shown both objects in a new location and asked ‘where is the modi’. Experiments 7 and 9 follow the same timeline with the addition that step 5 occurs in a different posture from all other steps. (The individual shown in this figure has given written informed consent (as outlined in PLOS consent form) to publish this image).
Fig 5.
Comparison between the Child and Robot data showing the means of the proportion of correct choices (and standard error of the means) for all experiments, and using the low-learning rate robot data.
Dotted line denotes chance, p < 0.05. Specific values for the child data and the robot data is as follows: For the Original Baldwin task, when objects and names were separately linked to the same posture, the robot correctly mapped the name to the target (Exp1), M = 0.71 (SD = 0.41), at above chance levels, t(19) = 2.2, p < 0.05, d = 0.51. Infants also correctly mapped the name to the target (Exp6), M = 0.71 (SD = 0.20), at above chance levels, t(15) = 4.16, p < 0.001, d = 1.04. In Experiment 2, where the locations of objects was switched, the robot failed to map the name to the target, M = 0.46, p = 0.64, but did so reliably less often than in the standard Baldwin condition t(38) = 0.03, p < 0.05, d = 0.58. In the Baldwin task with posture change, when Step 5, the naming event, was experienced in a new posture, the robot (Exp3) and the infants (Exp7) failed to map the name to the object, both preforming at chance Robot; M = 0.42, p = 0.85, Child; M = 0.41, p = 0.16, and did so reliably less often than in the standard Baldwin Task where there was no posture shift; Robot; t(38) = 2.49, p < 0.05, d = 0.78, Infant; t(30) = 3.73, p < 0.001, d = 1.32. In the Interference task, the toddlers showed the same interference effect as the robot, and as the toddlers in Samuelson et al., 2011; when the target object was explicitly named at a location and posture associated with the distractor object, both the robot (Exp4) and children (Exp8) selected the target referent at below chance levels however only the child data was significantly below chance, M = 0.36 (SD = 0.4), t(19) = -1.5, p = 0.07, d = 0.34, Robot data p = 0.07. For the Interference task with a posture change, when the Phase 1 experiences were distinguished from the Phase 2 naming events by a poster shift, although performance was not above chance, both children (Exp9) and the robot (Exp5) the interference effect present in Experiment 4 & 8 was reduced p = 0.09 & p = 0.13 respectively. However for both child data and robot data the named target in the posture shift condition was reliably selected more often than when there was no posture shift Child; t(30) = -2.59, p < 0.05, d = 0.91, Robot; t(38) = -1.87, p < 0.05, d = 0.24.