1. Krista Willey Animal Behaviour 436-01
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Testing Episodic Memory Capabilities and Limitations in Dogs of Various Breeds and1
Ages2
1,405 words3
4
Introduction5
Episodic memories are memories that can be attributed to personal history and6
experiences. Episodic memories allow attachment to specific memories and storage of7
these memories as a type of linear progression in the mind, so one can remember when8
and where it happened (Roberts, 2002). Episodic memories allow organisms to change9
and direct their own behaviour due to past experiences, no matter how menial (Li &10
Schwartz, 2013). Selivanova (1976) discusses how short-term and long-term memory are11
conditioned reflexes. These reflexes can develop separately based on certain receptors12
that are available in the brain of the species. According to Selivanova (1976), when the13
brain contains mass amounts of armin, these attach to cholinoreceptors and it hinders the14
short-term memory as well as certain aspects of long-term memory; so those species that15
are unable to retain short-term memories easily have more difficulty transferring16
information into their long-term memory as well. The reason the attachment to the17
cholinoreceptors hinders short-term memory is because their retention span is decreased18
and the organism simply does not respond as drastically to outside stimuli.19
Since there are no specific agreed-upon linguistic behavioral markers in animals20
like there are with humans, episodic memory in relation to animals is often considered21
episodic-like memory (Clayton, Bussey, & Dickinson, 2003). Clayton and Dickinson22
(2010) concluded blue jays and hibernating animals rely on episodic memory for23
recovering food they cached. Dogs may not have had short-term memory conditioned24

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over time since they do not rely on it as heavily as the species that use short-term25
memory, specifically for communication and survival, like blue jays, since they often26
have a caretaker. Experiments have been done to test dogs’ abilities to recall and repeat27
an event based on a previous experience in order to test delayed matching (Fujita, et al.,28
2013).29
The issue is these experiments tested whether dogs have the same episodic30
memory capabilities as humans, rather than if they have any remnants of episodic31
memory. Testing to see if there is any remnant of episodic memory would occur by32
seeing how long the species can retain the information instead of measuring whether they33
can remember it for a one specific amount of time. Fujita, et al. (2012), successfully34
tested episodic memories in dogs; however, they used food as a motivation, which can35
create a stronger memory for the dogs. According to Bein, et al. (2015), creating36
congruent pairs creates better memory recalls for retrieving information. The proposed37
experiment will be testing the limitations on dogs’ episodic memories, to see if they can38
withhold any amount of arbitrary information. Lind, Enquist & Ghirlanda (2015) believe39
arbitrary events not triggering specialized memory systems cannot be remembered for40
long periods of time. Dogs lack the ability to create long-term memories of arbitrary41
events or images and therefore do not express episodic memories.42
Fugazza (2013) mentions dogs have a higher chance of recalling information if43
someone indicates their preference towards it, this will be useful for giving the treat for44
stimuli 1 recognition so the dog can hopefully retain the image for a longer amount of45
time. Giving the dog a treat for recognition is a form of positive reinforcement and is46
often used in training dogs to remember a specific behaviour or command. Gonzalez, et47

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al. (2013) results showed no significant difference in memory and performance48
capabilities for dogs of different ages and training levels, so age and training level will49
not be taken into consideration for this experiment. If untrained dogs can express50
recognition towards the original stimuli presented in this experiment after a time-delay of51
3 minutes, then they show competency to develop introductory episodic memories. Since52
previous studies show dogs cannot retain information past a certain amount of time, this53
competency could mean dogs have been conditioned since previous studies to use54
episodic memory more often. Dogs are being trained to hunt, retrieve objects, and sniff55
out particular scents more often nowadays, so this could be conditioning dogs episodic56
memory since retaining information on where something is stored is being more useful.57
58
Figure 1. Process list of scientific method for testing episodic memory capabilities in the59
current study and limitations in dogs of various breeds and ages using presented stimuli.60
61
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Observation
• Dogs get excited every time they see someone no matter how long its
been
Question
• Why are dogs not remembering small pieces of information?
• How long can dogs remember menial information?
Hypothesis
• Dogs possess the ability to create and recognize long-term memories
based off arbitrary images
Prediction
• If dogs can express recognition towards the original stimuli presented
in this experiment after a time-delay of three minutes, then they show
competency to develop introductory episodic memory.

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Methods63
This experiment was conducted at Blue Earth Nicollet County Humane Society64
(BENCHS). Each dog was presented with stimuli in a separate room away from all other65
animals and human interactions can be monitored so the distractions of the dog are66
limited. Inanimate pictures were used as the stimuli in order to prevent bias by the dogs67
choosing one object over the other. When each stimulus was shown, the name of the68
stimuli was stated once in order to create the congruency effect discussed by Bien, et al.69
(2015). If something was congruent, it meant objects were in harmony and had something70
similar. Since different shapes were used for this experiment, congruency had to be71
created in a different way. The shapes were the same size, on the same size sheet of72
paper, and the vocalization of stating the shape when presented created an even greater73
congruent effect.74
Each dog was shown the same image of a blue square (stimuli 1) for 1 min. After75
a 30-sec delay, the dog was shown stimulus 1 min. After another 30-sec delay, the dog76
was shown stimulus 1 along with a yellow circle (stimulus 2) at the same time for 1 min.77
If the dog identified the original stimulus, they were rewarded a treat. After a 2-hour78
break in between tests for the same dog, they were retested with a 60-sec delay. This79
method was repeated eight more times, giving a 300-sec delay at the end. Recognition of80
the stimuli was considered if one of the following codes are noticed: TW, L, or S.81
Regression was used to analyze the data to calculate to probability deviations of data82
collected happened by chance. Once the data was collected, it was be put into a table83
comparing how many dogs did and did not recognize the original stimuli based on time.84

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The amount of dogs that recognized the original stimuli was graphed as the dependent85
variable against the time delay to show any general trends that occurred.86
If the dog expressed the codes or code combinations: L, S, TW, L & S, L & TW,87
or S & TW it was considered to be recognition for the original stimuli. If the dog88
expressed the codes or code combinations: HT, L & HT, or TW & HT it was not89
considered recognition towards the original stimulus. In order to create the regression90
analysis, dogs that showed recognition were given a 1 and no recognition was be a 0.91
These were placed next to the time delays for each dog and then I regressed Y on X to92
test for the significance of the linear relationship.93
Table 1. Ethogram of observed behaviours while testing episodic memory capabilities94
and limitations in dogs of various breeds and ages using stimuli.95
Behaviour Code Description
Head tilt HT The dog tilts their head to either side; this often
indicates confusion.
Tail wagging TW The dogs tail moves back and forth either
vertically, horizontally, or moves circularly; this
often indicates excitement.
Locomotion L When the dog is moving towards the stimuli.
Sniffing S When the dog is near the stimuli and uses their
nose to smell the stimuli; this often indicates
curiosity and is used as a form of recognition.
96
97
98
99
100
101

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Table 2. Time method for presenting stimuli to each individual dog undergoing the102
experiment. Nothing indicates neither stimulus is presented, this gap increases each round103
in the experiment. There will be a minimum of a two-hour break for each individual dog104
before they are retested with a longer period of time with no stimuli presented.105
Time (seconds) Event
0-60 Stimuli 1
60-90 Nothing
90-150 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-120 Nothing
120-180 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-150 Nothing
150-210 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-180 Nothing
180-240 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-210 Nothing
210-270 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-240 Nothing
240-300 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-270 Nothing
270-330 Stimuli 1 & 2
BREAK FOR TWO HOURS
0-60 Stimuli 1
60-300 Nothing
300-360 Stimuli 1 & 2

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Results106
In the beginning of this experiment when there was less time delay between107
stimuli presentation, the dogs reacted more strongly towards the stimuli and showed clear108
recognition. When the time delay was greater and nearing 300 seconds, the number of109
dogs that showed recognition was lower. The trendline from figure 2 shows this110
correlation. The p-value from analysis was less than 0.001 and the analysis stated the null111
hypothesis was rejected.112
113
Figure 2. Comparison of dogs that showed recognition towards the original stimuli when114
both were presented to the time delay between images. The trendline showed a downward115
slope the longer the time delay.116
117
118
0
2
4
6
8
10
12
14
16
0 50 100 150 200 250 300
ShowedRecognition(dogs)
Time Delay (seconds)
P-value= <0.001

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Discussion119
Figure 2 shows a significant negative relationship between dogs expressing120
recognition after longer time. The p-value showed on figure 2 shows a there is a121
significant difference between dogs showing recognition or not with a longer time delay.122
The longer the time delay, the less likely a dog is to express recognition of the stimuli.123
This experiment rejects the hypothesis that dogs possess the ability to create and124
recognize long-term memories based off arbitrary images. The rejection of the null125
hypothesis done by the regression analysis means the test showed a significant126
relationship between longer time delay and recognition.127
This experiment shows results similar to other studies that have been conducted128
regarding episodic memory in dogs. Lind, Enquist & Ghirlanda (2015) stated that dogs129
cannot retain information unless a specialized memory system is triggered from an event130
or stimuli presented. The rejection of this hypothesis indicates that dogs may not have131
had to develop episodic memory like some animals that require caching because it has132
never been a survival necessity for them. Future studies resulting from this experiment133
would be using a more visually appealing image as stimuli. This experiments difficulty134
stemmed from there being no agreed-upon linguistic behavioral marker that signify135
exactly what an animal is thinking, so deciding whether a dog recognized a stimulus is136
dependent on each experiment and can vary.137
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