Increasing Donations to Supermarket Food-Bank Bins Using Proximal Prompts

Abstract

There has been little research into interventions to increase participation in donating items to food-bank bins. In New Zealand, there has been an increased demand from food banks (Stewart, 2002). This study demonstrated that point-of-sale prompts can be an effective method of increasing donations to a supermarket food-bank bin.

In New Zealand, there has been an increase in people seeking assistance from food-bank organizations, sometimes necessitating rationing (Stewart, 2002). Food donations come from various sources, including supermarket food-bank bins.

Prompting, particularly proximal prompts, can increase socially desirable behavior such as seat-belt use (Thyer & Geller, 1987) and donations to senior centers (Jackson & Mathews, 1995). Point-of-sale (POS) signs, placed next to items on sale, have been shown to function as effective proximal prompts to increase purchases of products (see McKinnon, Kelly, & Robinson, 1981, for a review). The current research was conducted to evaluate whether POS signs would be a cost-effective method to increase the number of items donated to a supermarket food-bank bin.

Method

Participants and Setting

Participants were patrons of a supermarket located in a suburban area of a city of 110,000 people. The supermarket was 1,627 m² in size, with three entrances and nine check-out lanes. The food-bank bin was behind the check-out lanes, near the main exit door.

Apparatus

The food-bank bin had been in place for 9 years. During the intervention phases, 10 computer-generated signs (15 cm by 10.5 cm) were placed in plastic display pockets (15.5 cm by 11.5 cm) hanging from the front of the shelves (alongside pricing information) by nonperishable food items on sale. The main message on the sign (in 32-point font) read “HOW ABOUT BUYING ONE FOR THE FOODBANK BIN” followed by “Thank you” (in 16-point font). Below and to the right of the main message was a drawing of a paper bag filled with groceries. At the bottom of the sign were directions about how to find the food-bank bin (in 16-point font) and the names of the four food-bank sponsors (in 12-point font; e.g., “Salvation Army”). During all phases, a sign (21 cm by 29.7 cm), with the words “FOODBANK BIN” in bold capital letters (96-point font) and the same computer drawing and recipient organization names (in 18-point font) as presented on the POS signs, was attached to the food-bank bin.

Experimental Design

This experiment employed an ABAB design with a follow-up 2 months later. Each of the five phases (including follow-up) lasted 2 weeks. During the intervention and follow-up phases, supermarket personnel were to move signs each week to new items on special. During baseline phases, the POS signs were removed.

Procedure

For both baseline and intervention phases, two observers counted (on two of three counting days per week) the donated items and independently recorded brand names and contents. A felt pen was used to mark items as they were counted to enable easy identification of newly donated items. Each observer then independently found and recorded the price of each item. Donations were counted on Tuesdays, Thursdays, and Saturdays, and food-bank organizations collected donated items on Wednesdays.

Results and Discussion

Interobserver agreement was 100%. The value and number of items donated per week were graphed for each phase of the study (see Figure 1). The mean and standard deviation of the number of items donated in each of the study's phases were as follows: Baseline 1 (M  =  1.67, SD  =  1.03), Intervention 1 (M  =  7.5, SD  =  2.07), Baseline 2 (M  =  2.5, SD  =  1.05), Intervention 2 (M  =  8.5, SD  =  2.07), and follow-up continuing Intervention 2 (M  =  9.33, SD  =  5.61). The value of items corresponded closely with the number of items donated (Figure 1).

Figure 1. Value ($NZ) and number of items donated to the food-bank bin each data-collection day in phases without POS signs, with signs, and follow-up (with signs).

During the follow-up phase, proximity of items donated to the POS signs was recorded. Of the 56 items donated during this period 2% were from a shelf on which a POS sign had been placed, 16% were in close proximity (defined as one shelf above, below, to the left, or to the right of a sign), and 82% were not in close proximity to a POS sign (by this very strict definition).

Overall, the number of donations in both intervention phases was significantly greater than during baseline phases (p < .005). Baseline phases did not significantly differ from each other, nor did any of the intervention phases differ from each other.

Based on a cost-benefit analysis, for 1 year, of the ratio between the cost of materials ($NZ5.70 total) and the increased donation values during intervention (including follow-up) phases of the study ($NZ65.81 per week), POS signs provide an overall benefit of $NZ3,422.12 per year. Note that the cost values are fixed amounts. An increase in expenditure would not increase donations in any one venue.

These results represent a replication and extension of previous results showing that prosocial behavior can be increased using systematic prompting procedures (e.g., Jackson & Mathews, 1995). Previous research has shown that sales may be increased using proximal prompts (McKinnon et al., 1981); the current study demonstrated that POS signs were a cost-effective method for increasing donations to a food-bank bin. Although the current results indicated that the majority of items donated were not located in close proximity to the signs, this may be a function of the strict definition of proximity. Future studies may address the extent to which the location of proximal prompts influences donations (e.g., it may be that prompts are effective when located anywhere in the store rather than in close proximity to specific items). The social significance of these outcomes is illustrated by reports that food banks are often unable to keep up with demand (Stewart, 2002). Four years after the initial study was completed, the POS signs are still being used.