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SE Kirk: Pathways to hyper-arousal in response to infant distress

Faculty: Science and Engineering

Supervisors: Dr Elizabeth Kirk; Dr Jacob C Dunn; Dr Matthew Bristow

Location: Cambridge

The interview for this project is expected to take place on Monday 15 April.

Apply online by 3 March 2024

Infant crying serves an evolutionary function, signalling distress to caregivers who are hardwired to be aroused by this stimulus, thus eliciting caregiving and promoting survival. Unfortunately, infant crying can also trigger abuse by parents who demonstrate hyper-arousal in response to infant distress (e.g., Frodi & Lamb, 1980).

One study reported that 5-6% of parents have smothered, slapped, or shaken their baby at least once because of its crying (Reijneveld et al. 2004)

Figures published by the NSPCC in 2018 recorded that 220 infants had died from shaken baby syndrome (also referred to as non-accidental head injuries) in the UK in the previous decade.

There is a concerning upward trend in recent years, which has been attributed to the pressures of the pandemic and the worsening financial crisis.

Studies examining physiological responses to stress go some way to explaining the mechanisms by which some individuals may show heightened reactivity to infant distress.

The hypothalamic-pituitary-adrenal axis (HPA), as measured by cortisol, is known to be affected by infant distress cues (Byrd, Calvi & Kennison, 2016). The enzyme alpha-amylase (sAA) is also reported to react to physiological and psychological stressors, providing a marker of autonomic nervous system activity (Nater et al. 2005).

Finally, decreased heart rate variability (HRV), indicating disturbed autonomic nervous system function, has been associated with mental stress, and signals a lack of ability to respond (Horsten et al. 1999).

Thus, physiological hyper-reactivity is proposed as a mechanism to explain why some individuals are more susceptible to harsh caregiving (Out et al., 2010).

Our current work uses lab-based studies that measure adults’ self-reported responses (intentional response and aversiveness rating) in response to audio samples of infant emotional signals (crying and laughter), in addition to collecting saliva samples and measuring heart rate variability to measure physiological arousal.

One of the key novel components of this research is that we are analysing the acoustic properties of the cry and laughter stimuli (duration, frequency, amplitude and non-linear phenomena) and will test the contribution that this has on participants’ stress responses to the stimuli.

The PhD programme of research will extend this work to further identify the risk factors that presuppose an individual to hyper arousal in response to infant distress in a larger sample.

The supervisory team brings interdisciplinary expertise on developmental psychology, perinatal mental health, biological markers of stress, bioacoustics and emotional signalling.

The successful candidate will be well supported by the team, which has experience in PhD supervision and can offer the student training in various methodological and statistical processes and packages.

The PhD programme will involve experimental studies and collection and analysis of human tissue, working with the ARU Biomarker Laboratory. The successful candidate will also be trained in the analysis of acoustic signals using specialist software.

The PhD programme will involve stakeholders (e.g. professionals supporting families with crying, and parents) to inform and guide the direction of the research. Below is an indicative summary of the proposed studies:

  • Proposed Study 1a: Analysis of bioacoustic properties of negative and positively valanced infant auditory emotional signals and the relationship this has to stress responses.
  • Study 1b: Experience of trauma (adverse childhood experiences) will be tested as a predictor of hyper-arousal to infant distress in lab-based study.
  • Study 2: A cross-sectional study of pregnant women in trimesters 1, 2 and 3 to examine changes in responses to auditory and visual infant emotional cues (i.e. infant cries, laughter and ambiguous facial stimuli, normed from study 1).

This PhD programme would suit someone with an undergraduate degree in psychology or life sciences. A strong understanding of experimental design is required.

If you would like to discuss this research project, please contact Elizabeth Kirk: [email protected]

Apply online by 3 March 2024

Funding notes

The successful applicant for this project will receive a Vice Chancellor’s PhD Scholarship which covers the tuition fees and provides a UKRI equivalent minimum annual stipend for three years. For 2023/4 this was £18,622 per year. The award is subject to the successful candidate meeting the scholarship terms and conditions. Please note that the University asserts the right to claim any intellectual property generated by research it funds.

Download the full terms and conditions.