'Effects of scarcity on child-directed speech' (AsPredicted #7813)
Author(s) This pre-registration is currently anonymous to enable blind peer-review. It has 3 authors.
Pre-registered on 01/13/2018 07:16 AM (PT)
1) Have any data been collected for this study already? It's complicated. We have already collected some data but explain in Question 8 why readers may consider this a valid pre-registration nevertheless.
2) What's the main question being asked or hypothesis being tested in this study? We hypothesize that having parents engage with their own experiences of scarcity will systematically reduce how much they talk to their child (child-directed speech, CDS) in a subsequent play session. Specifically, caregivers and their three-year-old children will be invited into the lab. The child will complete an unrelated experiment with the experimenter while the caregiver completes an online survey that serves as the manipulation. Next, the researcher will leave the child and caregiver alone with a puzzle box toy for 10 minutes, under the guise of going to retrieve another survey. Caregivers will be recruited from a convenience sample in the Berkeley area that tends to be highly educated and high-income.
3) Describe the key dependent variable(s) specifying how they will be measured. Quantity of CDS: number of parent word types and tokens during the free-play session.
Quality of CDS: number and proportion of directive, elaborative, and decontextualized utterances produced.
4) How many and which conditions will participants be assigned to? Participants (i.e., caregiver-child dyads) will be assigned to one of two conditions: a scarcity condition, in which caregivers are asked to reflect on 3-4 experiences of scarcity over the last week, and a control condition, in which they are asked to reflect on 3-4 things they did over the last week.
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis. Quantity of CDS: As our primary analysis, we will perform a two-sample t-test to compare word types and tokens between caregivers in the control condition and those in the scarcity condition. We predict that caregivers in the scarcity condition will produce fewer word types and tokens than those in the control condition.
Quality of CDS: Next, we will perform a two-sample t-test to compare quality measures of CDS between caregivers in the control condition and those in the scarcity condition. We predict that caregivers in the scarcity condition will produce relatively more directives, and fewer elaborative and decontextualized utterances.
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations. Participants will be excluded if another child or adult is present during the play session; if the parent speaks a language we cannot transcribe; if the child has a diagnosed language or learning delay; if the caregiver does not complete the manipulation (e.g., writes only one scarcity experience); if the caregiver or child does not comply with the experiment (e.g., child is too fussy to continue, dyad exits the room we leave them in); or if no video/audio is recorded.
7) How many observations will be collected or what will determine sample size? No need to justify decision, but be precise about exactly how the number will be determined. 100 participants; 50 per condition.
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?) Child utterances: We will also examine child word types and tokens during the free-play session, including the number of utterances the child produces and the proportion of child to caregiver utterances. We predict that children in the scarcity condition may produce more words and/or utterances than those in the control condition, if their caregivers are not providing them with the level of verbal scaffolding they are accustomed to.
Variation over time: In addition, we will analyze whether the quantity and quality of child-directed speech varies over the 10 minutes following the manipulation. One possibility is that group differences will reduce as time from the manipulation elapses; another possibility is that differences will continue to widen as caregivers in the scarcity condition may fatigue more rapidly.
Other variables collected for exploratory purposes – following the play session – include caregivers’ self-reported education and income levels, positive and negative affect, and self-reported feelings of scarcity. As exploratory analyses, we may also examine the valence of the child-directed speech that caregivers produce during the free-play session.
13 participants have completed the experiment; the first 6 videos only have been viewed and transcribed in order to ensure that the play session provides sufficient opportunity for child-directed speech.
