Individual differences in banknote processing: the role of altruism

The value of banknotes: relevance of size, colour and design

In the current study, we evaluate the relevance of three physical features when people retrieve the monetary value of banknotes. To this end, three monetary comparison tasks were designed in which in each trial a pair of banknotes were presented and participants selected the one with higher monetary value. In each task, a different banknote feature (size, colour and design) was examined and a congruent and an incongruent condition (the value of the physical feature corresponded or not to its actual value, respectively) were compared to a neutral condition (no information about the physical feature was provided). We found a pattern of facilitation and interference effects which suggests that size is the most relevant physical feature for accessing the monetary value of banknotes followed by colour. However, the availability of a variety of designs across banknotes seemed not to facilitate the performance of the task, but rather the opposite, hindering the monetary comparison task.

The processing of prices across numerical formats

We evaluated whether the format in which prices are presented determines the processing of their magnitude. A price comparison task was used in which two-digit prices with Arabic digits, written number words and auditory number words were presented in the euro currency. Prices were number-monetary category (NMC) compatible (49 euros - 36 cents) when the number and monetary category of one price were larger than those of the other (49 > 36, euros > cents); or NMC incompatible (49 cents - 36 euros) when the number of one price was larger but the monetary category smaller than those of the other (49 > 36, cents < euros). In addition, there were unit-decade (UD) compatible prices when the decade and unit of one price were larger than those of the other (49 euros - 36 cents, 4 > 3, 9 > 6); and UD incompatible prices when the decade of one price was larger but the unit smaller than those of the other (46 euros - 39 cents, 4 > 3, 6 < 9). The results showed NMC compatibility effects in all numerical formats. However, the UD compatibility effect was not found in any numerical format. The results are discussed within the hybrid model of multisymbolic magnitude processing.

How do we process prices? Electrophysiological evidence of componential analysis

The aim of this study was to evaluate if the processing of prices (e.g., 8 euro) involves separate analysis of the digit (8) and the monetary category (euro). Event-related potentials (ERPs) were recorded when participants performed a price comparison task in which a pair of prices was presented and they selected the one with higher monetary value. There were compatible comparisons where the digit and the monetary category of one price were higher than those of the other price (e.g., 7 euro - 4 cent, 7 > 4 and euro > cent), and incompatible comparisons where the number of one price was larger but the monetary category smaller than those of the other price (e.g., 4 euro - 7 cent, 4 < 7 but euro > cent). Compatibility effect modulated ERPs in the 350-450 ms time window, with more negative amplitudes in incompatible trials relative to compatible trials. This pattern of results suggests that prices were processed in a componential manner, challenging the evidences of the holistic model. The results of this study agree with the general model framework for multi-symbol number comparison: The constituents of a multi-symbol magnitude are processed and compared to each other separately in a componential manner.