Evaluating the Strange Situation Procedure (SSP) to Assess the Bond between Dogs and Humans

Abstract

The Strange Situation Procedure (SSP) is increasingly being used to study attachment between dogs and humans. It has been developed from the Ainsworth Strange Situation Procedure, which is used extensively to investigate attachment between children and their parents. In this experiment, 12 female beagle dogs were tested in two treatments to identify possible order effects in the test, a potential weakness in the SSP. In one treatment (FS), dogs participated together with a ‘familiar person’ and a ‘stranger’. In a control treatment (SS), the same dogs participated together with two unfamiliar people, ‘stranger A’ and ‘stranger B’. Comparisons were made between episodes within as well as between treatments. As predicted in FS, dogs explored more in the presence of the familiar person than the stranger. Importantly, they also explored more in the presence of stranger A (who appeared in the same order as the familiar person and followed the same procedure) than stranger B in SS. Furthermore, comparisons between treatments, where a familiar person was present in FS and stranger A was present in SS, showed no differences in exploration. In combination, these results indicate that the effect of a familiar person on dogs' exploratory behaviour, a key feature when assessing secure attachment styles, could not be tested reliably due to the order in which the familiar person and the stranger appear. It is proposed that in the future only counterbalanced versions of the SSP are used. Alternatively, since dogs reliably initiated more contact with the familiar person compared to the strangers, it is suggested that future studies on attachment in dogs towards humans should focus either on the behaviour of the dog in those episodes of the SSP when the person returns, or on reunion behaviour in other studies, specially designed to address dog-human interactions at this time.

Assessing positive emotional states in dogs using heart rate and heart rate variability

“…The dogs had previously participated in different studies investigating positive emotions [e.g. 10,12,16,17,18] and have been shown to be attached to their caretaker [19] and that interacting and being petted by a familiar caretaker is positive [18].…”

“…Four aqua-wet gel electrodes (KRUUSE ECG Electrodes; KRUUSE) were positioned on the animal's thorax according to instructions provided by the manufacturer (KRUUSE ECG and Holter montage) and the recording device was attached to a harness and positioned on the back of the dog. The dogs had worn the heart rate equipment in previous experiments [17,19], but were familiarized twice prior to the start of this study. Each dog was shaved on the thorax with a trimmer to reduce skin resistance and improve electrode contact.…”

Dog behavior but not frontal brain reaction changes in repeated positive interactions with a human: A non-invasive pilot study using functional near-infrared spectroscopy (fNIRS)

“…The interactions were performed by one specific human handler, to whom the dogs were attached. Attachment in these dogs had been demonstrated previously using the Strange Situation Procedure [13]. They had also previously performed an operant task to get access to a person who interacted with them, implying that interactions with a human handler had rewarding properties [14].…”

Awake canine fMRI predicts dogs’ preference for praisevsfood

“…Dogs are gifted at attending to, and interpreting, subtle human social cues (Lakatos et al , 2012; Merola et al , 2012; Müller et al , 2015), and a behavioral literature suggests that dogs act as if socially attached to humans (Topál et al , 1998; Palmer and Custance, 2008; although see: Prato-Previde et al , 2003; Rehn et al , 2013). Despite this, the motivations behind dog behavior toward humans can be difficult to disentangle from behavior alone.…”