Highlights
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In recent years, debates about animal consciousness have moved on from the question of whether any non-human animals are conscious to the questions of which animals are conscious and what form their conscious experiences take.
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There is an emerging consensus that current evidence supports attributing some form of consciousness to other mammals, birds, and at least some cephalopod molluscs (octopuses, squid, cuttlefish).
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If we try to make sense of variation across the animal kingdom using a single sliding scale, ranking species as ‘more conscious’ or ‘less conscious’ than others, we will inevitably neglect important dimensions of variation.
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There is a need for a multidimensional framework that allows the conscious states of animals to vary continuously along many different dimensions, so that a species has its own distinctive consciousness profile.
Keywords
The Emerging Science of Animal Consciousness
Are Some Animals ‘More Conscious’ Than Others?
P-Richness
E-Richness
Integration at a Time (Unity)
Integration across Time (Temporality)
Self-Consciousness (Selfhood)
Challenges for a Multidimensional Framework
Dimension | Experimental paradigm | Question being investigated | Refs |
---|---|---|---|
P-richness | Induced blindsight | Can blindsight-like phenomena be induced in the animal through lesions to specific brain regions? If so, what information typically reaches those regions? (Drawback: highly invasive). | [
19.
] |
Discrimination learning | Can the animal learn to respond differently to very slight differences between stimuli (and how small can the differences be)? | [
118.
] |
|
Reversal learning | When stimulus contingencies are reversed, can the animal rapidly learn that they have been reversed? This is potentially linked to consciousness in humans. | [
119.
,
120.
] |
|
Trace conditioning | Can the animal still learn stimulus contingencies when the stimuli are separated by a temporal gap? This is potentially linked to consciousness in humans. | [
24.
,
27.
] |
|
E-richness | Motivational trade-off | Does the animal weigh different needs against each other in a ‘common currency’ to make flexible decisions? | [
30.
,
33.
,
34.
,
35.
] |
Outcome devaluation and revaluation | If the value to the animal of a reward is manifestly changed, will the animal change its behaviour quickly? | [
121.
] |
|
Cognitive bias | Does the animal respond differently to novel stimuli depending on its affective state? | [
122.
] |
|
Emotional contagion | Is the animal susceptible to ‘catching’ the emotions of other individuals? | [
123.
] |
|
Unity | Interocular transfer | If the animal is conditioned to respond to a stimulus presented in one visual hemifield, can the same response be elicited by presenting it to the other hemifield? | [
44.
] |
Meta-control | If the two visual hemifields are presented with conflicting information, can the animal resolve the conflict? | [
124.
] |
|
Crossmodal integration | Can the animal integrate information from different sense modalities (e.g., vision and hearing?) | [
125.
] |
|
Visuo-spatial bias | Does the animal exhibit visuo-spatial biases in behaviour (e.g., a preference for using a particular eye to guide a particular task?) | [
108.
,
126.
] |
|
Multitasking | When given two tasks simultaneously (e.g., foraging and watching for predators), does the animal divide the labour between the two hemispheres? | [
126.
] |
|
Electroencephalograph studies of sleep | Does the animal exhibit unihemispheric or bihemispheric sleep? | [
45.
] |
|
Temporality (timescales <1 s) | Apparent motion | Can the animal respond differently to moving and static images? Can it make inferences from video images to real moving objects and vice versa? | [
127.
] |
Temporality (timescales >1 s) | Episodic-like memory | Can the animal simultaneously remember ‘what’, ‘where’, and ‘when’ about a specific past event? | [
128.
] |
Source memory | Can the animal remember information about how a memory was acquired (e.g., by vision or by smell)? | [
57.
] |
|
Memory integration | Can the animal update old memories with new information? | [
90.
] |
|
Future planning | Can the animal flexibly and spontaneously plan for a future event, and for future desires, without relying on reinforcement learning? | [
129.
] |
|
Selfhood | Mirror-mark | Does the animal recognise a mark seen in a mirror as a mark on its own body? | [
66.
,
67.
,
68.
,
69.
,
70.
] |
Body awareness | Can the animal recognise the position of its own body as a potential obstacle to success in a task? | [
130.
] |
|
Experience projection | Can the animal predict how others are likely to behave in a scenario on the basis of a specific past experience it had in the same scenario? | [
74.
,
76.
] |
Concluding Remarks
Acknowledgements
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