Cross Category Effects
Cross category effects (Hofstetter et al. 2006), also termed technology rebounds by Weidema (2008)), relate to technology changes that affect the availability of other technologies or alter their effect on the available household resources. An example is the parallel use of a product A, enabled by a new product B, while not relevantly impacting on each other's functions. An example is the use of a laptop during a train travel (enabled by the portability of the computer and by the trains power outlet and Wi-Fi access). This situation can be argued to free time, as the work on the laptop is working time, if assuming that total working time is not increased.
Other effects are more indirect and can interact with other mechanisms on society level, affecting e.g. infrastructure availability.
Mental Secondary Consequences
The knowledge (or sometimes only belief) that a product X is more environmentally friendly may lead to an additional consumption “because the product X has less impacts”, as Girod et al. (2010) argue. Examples are the more fuel-efficient car or more energy-efficient lighting that lead to driving further or having more lamps, respectively.
Similar to the use of freed household resources, also the mental consequences can lead to more use of the same product, as in the above examples, of products that fulfil the same function or meet the same need, or of other products or activities (e.g. “because I separate my waste, it is ok that I …”). These mental consequences can also be interpreted as having a mental budget for environmental impacts, as Girod et al. (2010) suggest. However, this mental budget is less accurate than the income or time budget and we can easily be misled as to the actual environmental benefit of a product.
Next to such negative secondary consequences that were in focus in previous work, the authors argue here that these can also be positive: the individual may like the good feeling that e.g. the decision of “being a vegetarian for a week” trial gives and he/she becomes fully vegetarian. Or the positive feeling of knowing to do something good for the environment leads to the decision to adopt a more sustainable lifestyle, i.e. consumption decisions in other product categories and meeting other human needs.
Higher Order Consequences of Economic Transactions
In addition, spending the saved money on other products means that this money is made available to individuals in a different product's supply chain. The net effect of the individual's available household income is hence not only depending on what he/she spends it, but also on the net change in impacts due to changed consumption depending on where the money that is being spent is going: buying a banana from Gran Canaria will – next to the local retailer – bring income to the wholesale/ importer and the Spanish farmer. Buying it from Costa Rica will bring the income to people in different countries and cultures. The spending of additional income can be expected to differ between cultures, age classes, education levels, and between different income groups. If we however assume for simplification that the consumption profile of the different supply-chains do not differ from each other, the secondary consequence in the supply-chain is zero and the net effect is exclusively the extra consumption by the consumer.
-  This does not yet consider that personal and corporate taxes modify the available income for consumption in the supply-chains. Still, if we assume that the taxes are used for purchase or investment by the governments, the money is still used for consumption, albeit with an again different consumption profile